Charles Céleste Hutchins – Page 7 – Les said, the better II

Trying to Cycle to Brighton

For the second time in my life, I’ve tried to cycle from London to Brighton. The first time was a decade ago and my girlfriend at the time sprained her ankle in Lewisham. She was determined, but in Croydon, she was forced to admit defeat and we turned back. I kept the map, though.

There’s a few changes. The route no longer starts at Cutty Sark.

It’s a wee bit north of there now and you can’t see the start sign from following the extension of (21).

It still winds through Greenwich, obviously, but the area has changed dramatically. When I first went along the route, the area was slightly alarming. There were neglected estates with burned sofas in front of their houses and cops knocking on doors. Now there’s a lot of construction displacing a really cool looking arts sector which likely displaced the residents there previously.

I found both times that taking route 21 to Croydon is a lovely relaxed ride that manages to wend through parks and offroad or low traffic paths until it gets to Addington, which is where I stopped for lunch.

There were a lot of blue ribbons tied to things, which I don’t know anything about.

Shortly after that the route got more rural and there were unpaved sections, which, because this is England, were lined with brambles and stinging nettles.

on the edge of Surrey — I’m smiling because I don’t realise what’s in store for my legs and tyres.

As I got into Surrey, the offroad paths got less and less well maintained. They were made up mostly of loose gravel. A lot of them has deep gulleys running through the middle, where water had drained down them. They looked like they hadn’t been maintained in quite some time. I don’t think they’re at all appropriate for touring.

The views were nice, though.

My original plan for this trip was to take my dog in a trailer and spend two days. I was persuaded instead, though to leave the dog behind and try to do it in one day.

I like to think of myself as an experienced touring cyclist, but it turns out that going slowly with a dog is quite different than going slowly without a dog. For instance, I don’t really have a good reason for my extremely glacial pace. The other is that if one is towing a dog trailer down a steep incline covered with loose rocks, there are a lot of things to worry about, but the bicycle flipping up over the handlebars is not one of them. I very nearly flipped my bicycle at least once and nearly bit it a few times.

A hole in the ground from hard breaking — A somewhat visible hole from trying to stop and not fall off.

It felt like I did a lot of time walking. Also, Gravelly Hill is very well-named.

As I got to the M25, the paths improved tremendously and the views were still very nice.

me at the M25 — I look disturbed because it’s been a long trip to only reach the M25.

I got to Red Hill, which was where I had been planning to sleep and it was already kind of late in the afternoon. I switched from the 21 to the 20 to get to Brighton. The shadows got longer. I looked at my map and saw that I had 25 miles to go and two hours until dark. The smart thing to do would have been to give up, but I pressed on until I got to a place called Hand Cross. My legs were trembling from exhaustion and twilight was falling. There’s no train station there and the infrequent buses were only going north, where I could get a train back south.

A cabbie pulled out of his driveway just a few meters away and I flagged him down to get a ride the rest of the way into Brighton. It was 40 minutes just by car.

Route 20 had been mostly been on extremely fast moving frontage roads next to the motorway. As I looked out the cab windows, I could see it continue, right in the pollution next to the road and I swear I thought I saw some section of it where it was actually on the margin of the motorway!

I went about 50 miles in all, which I’m very disappointed by. I could go the same distance normally with a dog. But, I did get almost all of the uphill and a lot less of the downhill and did get stuck walking a fair amount. The last part that I missed out on did not look like it was fun.

Indeed, I’m not sure how much any of it was fun. The on-road parts had aggressive cars coming much too close, especially around Croydon. The offroad parts were even more dangerous. I thought about who I could report the problems to, but as the UK is about to embark on economic self-destruction, there’s not much hope they’ll ever get fixed.

This is probably the last time I’m going to even bother trying to follow a national cycle route in the south east. Maybe they’re better in other parts of England or in Scotland, but the ones that set off from London seem to go to absolute shit once I get out of the sprawl.

Becoming British in a Troubled Time

What a time to become a subject!

Recently, I swore allegiance to the queen at a mandatory ceremony.

I’m now a citizen of the UK and of the European Union, although one of these citizenships is about to be stripped away. Alas. But I did have a fun party.

Almost immediately upon gaining full rights in my country, it was plunged into a constitutional crisis by a prime minister who has absolutely no mandate. He was selected by 75k members of his party: angry white extremely conservative middle class men from the home counties. They want the UK to leave Europe with no deal, however, parliament is not on board with this plan.

There has been a general election since the referendum, so parliament, unlike Johnson, does have a mandate to act on Brexit. However, using a clever move preferred by King Charles I, Johnson can use royal prerogative to suspend parliament and act without them.

For my non-British readers, it’s important to note that while Britain claims to have a constitution and sometimes whips itself into a crisis surrounding this constitution, nobody can point out the paragraph that is in question. Nobody can point to any document at all. It’s an unwritten constitution. All they have is tradition and precedent. Of course, I’ve just mentioned some precedent in the previous paragraph, but there are some important things to keep in mind about Charles I.

First of all is that he ruled a very long time ago and was a king rather than a PM. Secondly, and perhaps more importantly, he was beheaded for this behaviour.

The day that it became clear Johnson was poroguing parliament, there were spontaneous protests around the country. I went to Westminster to find the bridge blocked by demonstrators. I posted about this experience to my mastodon account, but will also summarise it here.

As I got to the bridge, there seemed to be two competing chants, which morphed into a call-response of “save our democracy / stop the coup”. Despite the bridge being blocked to automotive traffic and a long line of stopped buses, there seemed to be very few cops around. Cyclists and pedestrians were still able to get through, although many seemed to be confused.

I was slightly disappointed to see EU flags. I left mine at home on purpose. I feel like an assault on democratic processes is a larger issue than Brexit and that people on all sides of that issue might be alarmed by the PM’s actions. I would want anyone who was concerned about democracy to feel welcome.

It was not a large crowd, at all, just many people milling around in the intersection, singing and chanting. Other chants included, “You shut down the parliament / we shut down the streets.” A child stood near me was delighted to hear his mother singing “Oh Boris, you wanker!”

There seemed to be a wide diversity of ages present, although nobody elderly and few disabled people. It seemed to be about 70-80% white.

After a while, some fake-cops did arrive and began helping the buses get turned around. It was also starting to get dark and a lot of families left and people who had been out for hours started to go home. As the crowd thinned, the cops told people to disperse or be arrested. I chose to disperse and wandered down to parliament square where there were still many more people, also blocking traffic.

The anti-coup protest in parliament square

There were helicopters buzzing overhead and a much larger presence of regular police , who did a lot of marching around from one side of the square to the other. People in the road, like at the bridge were chanting and singing. A reporter from RT set up next to where I was standing. Some other protestors came up to him and joked, ‘So you guys are the ones who caused all of this!” But nobody was hostile to them, which I was slightly disappointed by, although unwilling to act alone.

Eventually, the crowd in the square decided to become a silent protest, which sucked a lot of energy out of things, although also it was getting late and people were leaving. Many of them sat down in the road and some speakers got up and gave Occupy-style “mic-check” speeches about what to do when they got arrested.

Large number of people sitting down at parliament Square

This advice included:

The police are not your friends. Don’t talk to them. Just say ‘no comment.’
Do not accept a caution. This benign sounding term is actually a criminal record.
If arrested, do not use the ‘duty solicitor’, but one of the activist ones who specialise in protest arrests.
If you are arrested, the only information that you are required to provide is your name, date of birth and address. You can wait until you appear in front of a judge to provide this, but there’s no advantage in waiting.
If you have a mobile phone, set it so the only way to log in is via a PIN. If you use a biometric login, the police can browse through it. The best thing to is to give it to a friend who is not being arrested.

As the crowd shrank, and the police outnumbered us, but nobody was being arrested, I started to wonder when last call was at the pub over the road. It turned out to be 11:15. When I got out, everyone was gone and I don’t know what happened to the last stragglers.

As I spoke to straggling drunks, however, one especially intoxicated you man said, “fucking American!” to me and forcibly grabbed my jacket. The other guy to whom I was talking peeled him off and sent him on his way.

As a citizen, I have a clear right to protest. But as soon as I open my mouth, I’ll always be foreign. The xenophobia brewing in the anti-democratic moves by the PM give me serious cause for alarm.

Successful sealant

I printed a small, self-contained mould in PLA for testing purposes. This section has the proportions that will hopefully be used in the final design, however, it does not need to join to any other sections of tentacle. I coated the pieces in PLA sealant XTC-3D.

I had previously been warned away from this sealant both because it’s fairly toxic and because the person selling it warned it may have an inhibitive effect on the silicon. I used the facilities that the University of Kent makes available for people working in resin to limit my exposure to the toxicity. I also coated the sealed mould in jelly vaseline, both to provide a barrier against any effects of the XTC and to make release easier. This was entirely successful.

The sealant did tend to pool and form drops which dried in place. This would reduce the thickness of the cast piece, so I adjusted the moulds to compensate for lost thickness. I also sanded off drops. Some of the sealant also created lumps that prevented the mould from shutting properly, so I chiselled those parts away.

Another difficulty was that the silicon I bought is too thick to pour into the top of the mould all in one go. It does not reach the bottom. The store suggested that I paint the inside of the mould with silicon, close it, mix up a second batch, and pour more in the top. This did not work.

The silicon pooled at the top and failed to fill the mould. This was partly because, the sealant had filled up all the small air channels that I’d left in the moulds, and thus air became trapped, leaving no room for the silicon to fill the mould. I then drilled out the holes, using a drill press due to a shortage of charged batteries.

I tried again using three separate pours and the result was much better, but still inadequate.

PlatSil Gel 00 is simply too thick to use in this kind of mould. The bottom of the mould (top of the picture) looks mostly alright, but there are still large airholes where air became trapped. Thinner silicon may solve this problem, or it may be necessary to put a third air channel at the apex of the arches in the mould.

I have lost access to the University of Kent’s workshop due to the School of Music and Fine Arts closing, so I’m hoping that just drilling through the existing moulds will be sufficient.

The flat piece of the design works extremely well with both this silicon and release agent, so the silicon I purchased will work for part of the final application.

Due to the aforementioned closing of the workshop and my loss of affiliation with Kent, I rushed to print and coat an entire three-part mould, despite not having time to test if my join design will work.

To reduce the need for chiselling, I tried using masking tape to cover all the parts where the moulds touch each other and seal. This did not work, however, it’s possible I just needed to remove the tape sooner.

The last picture shows a translucent white PLA. My previous batch of grey PLA was rescued from an incinerator by refil. By the time I ran out of it, they’d sold out, so I’ve switched to their normal supply of PLA, made out of recycled vegware – the alledgedly biodegradable cutlery and coffee cup lid plastic. As far as I know, this is not generally recycled in the UK, and it’s always better to use non-disposable items in cafes.

Next Steps

In my previous post, I had confessed to feeling discouraged, but I do think the latest efforts have turned a corner. Although I have lost access to my workshop, silicon is not at all toxic to handle and requires no special precautions, so I should be able to try pouring with more appropriate material at home.

My moulds may require more air channels, but I’m hoping this will not require reprinting them. Printed holes are contained by walls, whereas ones drilled through a print will open directly to the supporting grid of the print. 3d prints are not solid, but have a largely hollow matrix supporting the outside walls. Keeping a drilled hole clear may prove to be problematic, but even if this is the case, getting only a single good cast will prove that the concept is sound.

More tentacle attempts

After a failed print, I decided to rationalise my moulds. These are created via a parametric tentacle design program in OpenSCAD. Obviously, changing the mould requires program changes, but this time my goals were both to ensure that it can create a mould across a wide range of parameters for users who want unusual sizes and to include an optimal ratio of parameters based on actuator research.

My program does not cope with tiny sizes. It’s expected that tentacles designed with it will be nearly as long as the print bed of a Ultimaker or longer. However, it seems likely that optimal ratios will be constant across actuator sizes. I adopted the ratios given by K Ogura et al, developed for tiny actuators. (2009)

As their actuators are squared and mine still have rounded edges, it may be that these are not optimal, however, I do feel that the new, narrow mould has higher aesthetic appeal.

Silicon

Before trying to cast this, I went to the 4d Model Shop to discuss the difficulties I had with my last silicon cast. The person working around the casting section of the store is extremely knowledgeable and helpful. She suggested that what I needed was a lower viscosity silicone, but as I still have a quite a lot of the high viscosity left, she suggested I paint the mould with a small amount of it, close the mould, mix up a second small batch and pour that in the top. She suggested that may allow the silicon to flow through the entire mould before it sets. Unfortunately, the shop does not sell retarder.

She also told me that although silicon does not adhere to PLA, the porousness of a 3d printed PLA mould creates a lot of surface irregularity that silicon will flow into, making the two part mould extremely difficult to separate. The mould must first be sealed.

Epoxy sealant is toxic and may contain elements that prevent silicon from curing, so she suggested I experiment with a high gloss polyurethane sealant and then paint liquid Vaseline over that as a release agent.

I painted a single coat of sealant on one mould section, followed by the vaseline. I then mixed up a tiny batch of silicon. During this process, the scale turned itself off, so I was forced to estimate ratios of the two part compound. I therefore used two mould sections, one as a control group in case the haphazard ratio has curing problems.

The experimental section had a thicker piece of silicon and was made slippery by the Vaseline, which may be why it was more difficult to remove that the section that had no treatments.

My next steps will be to:

try a different sealant
try using more coats of the existing sealant
try using non-liquid vaseline to better cover over cracks in the mould
try using other household materials such as sunflower oil or sudo cream

Bioplastic

I’ve currently got a small batch of corn plastic drying, which is taking more than a week. The volume is decreasing significantly and I’m not sure it will be enough to make a test cast once it dried enough for me to melt it.

I’ve found some very promising research about using food waste to make bioplastic. The experiment was done using a dilute solution of hydrochloric acid – so dilute that vinegar is more acidic. I wish to see if vinegar would also produce this result, but it requires a food dehydrator and the ability to stir a solution at 40C for more than day – so a magnetic stirrer hotplate.

There is also research about citrus peels, specifically. This is perhaps the most interesting avenue. Pectins are stretchy like gelatin, which has been tested in actuators. It’s also easily available in my area. The processing is very much like other food waste processing, so the same equipment is required.

Feelings

This is all taking much much much longer than I thought it would and I have to say, I’m starting to feel extremely discouraged. While the 3d programming has turned out to be a lot easier for me than I anticipated, virtually everything else has been vastly more difficult. I was hoping to have some kind of prototype by autumn, but this looks less and less likely. My workshop access has been through my primary employer, the University of Kent. However, the department I teach in is closing and thus I’m becoming redundant over the summer. It’s still unclear whether the arts workshop is also closing at this time.

Cooking bioplastics in the kitchen is extremely unpopular with my spouse and I don’t really have space for a food dehydrator. I hope the London Hackspace may be able to help with this, however, they’ve moved rather a long way from the old neighbourhood.

Works cited

Bátori, V et al (2017). Production of Pectin-Cellulose Biofilms: A New Approach for Citrus Waste Recycling. International Journal of Polymer Science [Online] , vol. 2017, Article ID 9732329, 9 pages, 2017. Available at: https://www.hindawi.com/journals/ijps/2017/9732329/cta/ DOI: 10.1155/2017/9732329 [Accessed May 2019]

Keiko Ogura et al (2009). Micro pneumatic curling actuator – Nematode actuator. 2008 IEEE International Conference on Robotics and Biomimetics. [Online] Available at: https://ieeexplore.ieee.org/abstract/document/4913047 DOI: 10.1109/ROBIO.2009.4913047 [Accessed May 2019]

Perotto, G et al (2018). Bioplastics from vegetable waste via an eco-friendly water-based process. Green Chemistry, [online] 20, pp. 894-902. Available at: https://pubs.rsc.org/en/content/articlelanding/2018/gc/c7gc03368k/unauth#!divAbstract DOI: 10.1039/C7GC03368K [Accessed May 2019]

Edible Octopod?

Mould Revisions following a Pour Attempt

As reported in my previous post, I created some moulds out of PLA for silicon casting. The second version of the mould fit together well. It had a single pour hole in the larger outside block.

When pouring silicon into this hole, there was no route for air to escape the mould and the silicon was slow moving within the mould. The silicon began to harden before even a fraction of the pour was complete.

Despite the small amount of silicon that got into the mould, it was extremely difficult to open, showing that the use of a release agent is necessary. Also, the slowness of the pour shows that a retarder is required.

I’ve made two versions of an updated mould. The larger mould piece has additional channels for which silicon to flow in and small air channels for air to flow out. There are now two identical pour holes and two smaller air holes. The airholes are connected to a narrow channel running for the length of the mould, which connects to the topmost part of the internal cavities. This should allow air to escape and if some silicon gets into the channels, it should not cause a problem.

The other half of the mould has two new designs. The aesthetically superior one cuts out a round channel for silicon flow. This channel is the same diameter as the cut-outs of the other part of the mould, which should give it a unified look. However, this creates an overhang. As the tentacle will be cast in a soft material, it should hopefully be possible to peel the tentacle from the mould without doing it damage.

Because the overhang may fail, I’ve also created a version of that half of the mould that has narrower protrusions. This should also allow better pouring channels for silicon, but will cause the walls of the finished tentacle to be much thicker on the outside edge.

Bioplastic

In the mean time, I’ve been experimenting with bioplastic and food waste. PLA is sort of biodegradable and recyclable, but silicon is not.

Banana Peel Plastic

My first attempt at bioplastic was overly ambitious. Banana peels contain starch, so I used those. I used a lime peel as an acidic element to get free ions. I added coffee grounds as well. For preservative, I added a mixture of sage and tea tree essential oils. And used glycerol as the plasticiser.

Ingredients

1 lime (post juicing for another recipie)
3 banana peels
1 moka pot’s worth of spent coffee grounds
0.5 tsp tea tree oil
1 tsp sage oil
0.5 tsp vinegar
2 tsp glycerol

Procedure

boil the limes and insufficient amount amount of time. save the water.
boil the banana peels 30 minutes
dry the banana peels 30 minues
blend the fruit and coffee with enough lime water to make a paste.
cook until thickens
Apply to final shape
Bake at a low oven temperature to dry

Results

The shape I attempted to make was a flower pot, moulded over an empty jar. While the material did mostly bond together, it took more than a week to fully dry and has had some cracking.

Some of this may be due to how ripe the peels were- presumably this caused some of the starches to convert to sugars. Also, I failed to remove any parts of any peels, so fibres and stems got into the final product. While these were unintentional, they have probably aided the stability of the structure.

Corn Flour Plastic

My second attempt used corn flour (also known as corn starch), vinegar, salt, glycerol and coffee grounds.

For this, I used slightly more corn flour than I’d use for gravy, as much liquid as I would use for custard, a teaspoon of glycerol, a teaspoon of vinegar and a few pinches of rock salt.

I cooked all of the ingredients together until they started to thicken like custard. I then transferred the mixture to a takeway container and added a teaspoons of sage essential oil as a preservative. I applied the mixture to paper maché animal horns, and put it in the oven at a low heat.

These took a day to dry, but the plastic has come out successfully. While I don’t have any good measurements for ingredient ratios, it seems I used a large amount of glycerol relative to the corn starch. This created a very flexible rubbery plastic, not altogether unlike silicon in consistency.

Bioplastic Actuators

Previous research into bioplastic soft robotics is available. The paper, Soft Pneumatic Gelatin Actuator for Edible Robotics [DOI: 10.1109/IROS.2017.8206525], especially caught my fancy. While a theatrical robot falls outside of their potential applications (which charmingly suggests “food transportation where the robot does not require additional payload because the robot is the food.” (Shintake, et al., 2017, p 6221)), an edible robot is a biodegradable robot.

Using food for non food applications also has ethical issues, however. Part of my goal with bioplastics is to utilise food waste and as such, I will be investigating the possibility of highly flexible banana peel actuators. Although the starch in these peels is edible, it’s usually discarded. Using this for plastic thus reduces food waste and potentially may help highlight the culturally-based waste of edible items.

Finally, I can make this kind of plastic in my kitchen and don’t need to access a workshop.

First Tentacle Attempt

My first bioplastic tentacle section used an unmeasured corn flour plastic similar to the plastic above. It contained no vinegar but instead copious amounts of sea salt, as this also frees up ions and may help preserve the plastic. For additional acidity, I scavenged a lime that had not been juiced to the fullest possible extent and squeezed the remainder into the plastic. The preservative was 1 tsp tea tree oil. As I did not strain the lime, some pulp got in, probably rendering moot the various preservative attempts.

I brushed the inside of the mould with sunflower oil. Corn flour bioplastic starts to set even more quickly than silicon and there are really only a few seconds to decant it into the mould. As such, I did not use the pours holes, but instead spooned the plastic into the mould and struck the lid with my hand to force it down. Excess plastic leaked from the top and pour holes.

The drying process for starch bioplastic seems to rely on access to air, so it was still completely uncured after several days and was damaged by opening the mould to check on it.

Shintake et al, mentioned above, used gelatin-based bioplastic, which may be better suited to this application. This is also often a food-waste product, however, it’s made via an industrial process using waste from the meat industry (Etxabide, et al., 2017) and is not something I could really make at home. I’ll be looking at whether I can extract pectin from fruit peels and use it for plastic.

Unresolved Issues

As all the tentacles need to be identical, proper measurements and consistency will become extremely important.

My moulds are designed to create the tentacle in two parts which must be joined together with an airtight seal. While this seems straightforward in silicon, I don’t yet know how difficult it will be with bioplastic. Perhaps a hybrid silicon/bioplastic tentacle is the answer, as I do not actually want my robot to be eaten.

The durability of this material is also unknown. One design studio on YouTube says that essential oils act as preservatives, but it’s unclear how long this prevents decay.

References

Bilgin, E. (2013). Banana peel plastic – Science DIY. [online] Sites.google.com. Available at: https://sites.google.com/site/scidiy/diy-plastic/banana-peel-plastic [Accessed 7 May 2019].

Borroni, L. (2018). DIY bioplastics from orange peels and ground coffee – YouTube. [online] Youtube.com. Available at: https://www.youtube.com/embed/PrUjjzznwEE [Accessed 7 May 2019].

Etxabide, A., Uranga, J., Guerrero, P. and de la Caba, K. (2017). Development of active gelatin films by means of valorisation of food processing waste: A review. Food Hydrocolloids, [online] 68, pp.192-198. Available at: https://www.sciencedirect.com/science/article/pii/S0268005X16303605 [Accessed 7 May 2019].

Shintake, J., Sonar, H., Piskarev, E., Paik, J. and Floreano, D. (2017). Soft pneumatic gelatin actuator for edible robotics. 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS).

wikiHow Staff Editor (2019). How to Make Bioplastic. [online] wikiHow. Available at: https://www.wikihow.com/Make-Bioplastic [Accessed 7 May 2019].

Octopod

I’ve been working for several months on a soft robotics project, on which I’m making very slow progress. The goal is to create a soft robotic octopod (or hexapod) – basically an octopus with inflatable tentacles that can walk around.

I’ve been working on the tentacle design thus far. They’re to be trefoil tentacles. Here’s a video of the tentacles which gave me the idea:

My tentacles are hopefully going to be much longer and won’t look like that, probably. I’ve gone though several design revisions. Most of the early versions were hand-built in clay.

Life-like

I started by making something that looked like an actual tentacle. The idea was that I would make a cast of it in vinamold. I made clay models of spines, also cast in vinamold, that I was going to use to make wax spines. The spines would be dangled down inside the mould of the outer tentacle and silicon poured around them. Then, they’d be melted back out. The voids they left behind could be pressurised with air to make the tentacle move.

The problems with this design became quickly apparent, but the most major was the asymmetry of the exterior shape was going to make it difficult to calculate the angle of the tentacle. If all sides are equal, the pressure of the interior spaces correlates directly with the angle, but having varying thicknesses around the outside makes that much harder to compute.

Symmetric in Vinamold

The next version uses a single model for all three sides of the tentacle. The curved part faces the outside, and the flat parts are joined in the middle to make a triangular tube down the centre of the tentacle.

I made the spine out of wood (not pictured) and then sculpted around it with clay to create the outer skin layer. I cast both parts in vinamold.

The previous version had a vertical mould, but this one was horizontal. I suspended the wax spines in the mould by casting them around a thick wire, which I embedded into the mould for the outer skin.

However, the wax floated in the silicon and the horizontal pour caused lamination (peel-y, layers of silicon rather than a uniform solid). When I melted the wax out, the tentacle was not air tight. It was much thicker on the rounded side than the flat side.

Vacuum Moulded

I realised I could repair the troubled tentacle by casting just a flat side for the inside layer and gluing it and the outside layer together. The best way to do this would be to do the outside layer and the inside layers separately. I also wanted the layers to be thinner overall.

Once again, I made a model in clay, but this time was very careful to keep only a tin layer around the spine. I made a vacuum mould of the spine and then added a thin skin to that spine and took a second vacuum mould. With some help from the workshop staff, I built a holder for the pair of them, with a little funnel in the top.

I could make a vertical pour of the silicon, which would be much more likely to hold. However, the plastics didn’t align perfectly around the edges and when I did a test pour with a cornstarch solution roughly as thick as the liquid silicon, it leaked out.

3d Printed prototype

Almost every write up of soft robotics I’ve found uses 3d printing rather than hand sculpting. I decided to switch to this more conventional approach. Using OpenScad, I wrote a little program to create a parametric mould for a tentacle.

I have terrible luck with the 3d printer owned by Kent’s School of Music and Fine Arts and the first print glitched.

This was intended to be a short, self-contained third of a tentacle. The flat part on the left is the inside edge. The middle box is shows the outer edge. The part on the right provides the hollow sections for the void.

In addition to the print glitching, Cura silently resized it to fit into the printer, which would have made the walls too narrow. To prevent future glitches and to keep things at the correct size, I’m now printing every component separately.

Printing at Home

Almost all of the work up to this point was done in the worskshop of Kent’s School of Music and Fine Arts. I received extensive help and support from George Morris and Georgia Wright.

As the workshop was closing for Easter and I had bad luck with prints, a few people suggested I get my own printer. I got an Ultimaker 3, but was too impatient to do a self-contained, short full tentacle again.

To make a longer tentacle, it would need to be broken into sections. The first section is the length closest to the robot’s body. One end had no input or output of air. The other end has an output. The middle section has an input at one end and an output at the other. (This section can be repeated to create a much longer tentacle.) The end section has an input but no output.

I started with the first section. The end closest to the robot is at the top of this photo and then end that joins up with the subsequent section is at the bottom.

My first print did not fit together correctly, so I’ve changed the program and am trying again. The most recent version is the one pictured.

This is taking longer than I anticipated. However, over the course of things, I’ve learned to sculpt, to make rubber moulds, and to do vacuum moulding as well as other workshop-related skills.

I’m hoping to get an inflatable tentacle within the next few weeks.

The SynthDefs for my Christmas EP

As threatened, I have once again made some Christmas music.

If you enjoy (or hate it, or are indifferent), please consider donating to the UKLGIG. cafdonate.cafonline.org/111#/DonationDetails They support LGBTQI+ people through the asylum and immigration process. Their vision is a world where there is equality, dignity, respect and safety for all people in the expression of their sexual or gender identity.

Or, if you are in the US, please donate to the National Center for Transgender Equality secure2.convio.net/ncftge/site/Donation2;jsessionid=00000000.app268b?df_id=1480&mfc_pref=T&1480.donation=form1&NONCE_TOKEN=C5EA18E62F736227261DC4CE5C50ADBE

The notes in the 5 movements all come from the same pop song, but in 4 of the movements, they pass through a class I (accidentally) wrote called MidiMangler. It’s undocumented, but the constructor expects the kind of midi events that come from SimpleMIDIFile in wslib and the .p method spits out a pbind.

The instruments are some of the sample I used a couple of years ago, but the organ is new. It’s based on one from http://sccode.org/1-5as but modified to be played with a PmonoArtic.

SynthDef(\organ, {| freq = 440, gate=1, amp=0.25, pan=0 |
    // from http://sccode.org/1-5as
    var lagdur, env, saw, panner;

    lagdur = 0.4;

    saw = VarSaw.ar(Lag.kr(freq-440)+440,
        width:LFNoise2.kr(1).range(0.2, 0.8) *
        SinOsc.kr(5, Rand(0.0, 1.0)).range(0.7,0.8));

    env = EnvGen.kr(Env.asr(Rand(0.5, 0.7), 1, Rand(1.0, 2.0), Rand(-10.0, -5.0)), gate, doneAction:2);

    amp = Lag.ar((amp / 4) * (Lag.ar(LFClipNoise.ar(lagdur.reciprocal, 0.1), lagdur) + 1)); // tremolo

    panner = Pan2.ar(saw, Lag.kr(pan,1), env * amp);

    Out.ar(0, panner);
}).add;

The other instruments are the default synthdef *cough*, a Risset bell and Karplus Strong – taken directly from a help file with no changes. These are presented at the bottom for the sake of completion. The other sound is a bomb sample I found on freesound.

The video is taken from an atom bomb test video, but slowed down and stretched. I used ffmpeg to do this. The original film was 24 frames per second. I used a ffmpeg filter to create a lot of extra in-between frames and then, separately, changed the frame rate to be much slower. The original film was a bit over 20 seconds and got stretched out to 15 minutes. The really low frame rate is a bit choppy, but I think more tweening would have just increased distortion. The commands for that were:

% ffmpeg -i trees-bomb.mp4 -filter:v "minterpolate='fps=180'" 180trees.mkv
% ffmpeg -i 180trees.mkv -filter:v "setpts=33.4*PTS" strch180.mk

The other day, I read someone putting for the idea that apocalyptic thinking is so profoundly unhelpful as to be self-indulgent. Climate change is not going out with a bang, but a very prolonged whimper, whilst, for the duration, failing to make any significant changes. We can address it and avoid many of the worst impacts, but we need to get very serious about it immediately. If we can build thousands of expensive, terrifying bombs just in case there might be a war nobody wants, surely, we can afford to spend some of that resource averting a disaster that we know is actually coming.

SynthDef(\bell, // a church bell (by Risset, described in Dodge 1997)
    {arg freq=440, amp=0.1, dur=4.0, out=0, pan;
        var env, partials, addPartial, son, sust, delay;

        freq = freq * 2;
        sust = 4;
        amp = amp/11;
        partials = Array.new(9);
        delay = Rand(0, 0.001);

        //bell = SinOsc(freq);

        addPartial = { |amplitude, rel_duration, rel_freq, detune, pan=0|
            partials.add((
                Pan2.ar(
                    FSinOsc.ar(freq*rel_freq+detune, Rand(0, 2pi), amp * amplitude* (1 + Rand(-0.01, 0.01))), pan)
                * EnvGen.kr(
                    Env.perc(0.01, sust*rel_duration* (1 + Rand(-0.01, 0.01)), 1, -4).delay(delay), doneAction: 0))
            ).tanh /2
        };

        //addPartial.(1, 1, 0.24, 0, Rand(-0.7, 0.7));
        addPartial.(1, 1, 0.95, 0, Rand(-0.7, 0.7));
        addPartial.(0.67, 0.9, 0.64, 1, Rand(-0.7, 0.7));
        addPartial.(1, 0.65, 1.23, 1, Rand(-0.7, 0.7));
        addPartial.(1.8, 0.55, 2, 0, 0); // root
        addPartial.(2.67, 0.325, 2.91, 1, Rand(-0.7, 0.7));
        addPartial.(1.67, 0.35, 3.96, 1, Rand(-0.7, 0.7));
        addPartial.(1.46, 0.25, 5.12, 1, Rand(-0.7, 0.7));
        addPartial.(1.33, 0.2, 6.37, 1, Rand(-0.7, 0.7));

        son = Mix(partials).tanh;
        son = DelayC.ar(son, 0.06, Rand(0, 0.02));
        EnvGen.kr(Env.perc(0.01, sust * 1.01), doneAction:2);

        Out.ar(out, son);
}).add;

SynthDef("plucking", {arg amp = 0.1, freq = 440, decay = 5, coef = 0.1, pan=0;

    var env, snd, panner, verb;

    freq = freq + Rand(-10.0, 10.0);
    env = EnvGen.kr(Env.linen(0, decay, 0).delay(Rand(0, 0.001)), doneAction: 2);
    snd = Pluck.ar(
        in: WhiteNoise.ar(amp),
        trig: Impulse.kr(0),

        maxdelaytime: 0.1,
        delaytime: freq.reciprocal,
        decaytime: decay,
        coef: coef);

    //verb = FreeVerb.ar(snd);
    panner = Pan2.ar(snd, pan);
    Out.ar(0, panner);
}).add;

Canon Fodder

I’ve made Christmas albums the last two years and I feel sort of obligated to do another one, although this year is rather a late start.

I’m just listening to what spotify is telling me were my top tracks of 2018 and one lurking in there is the 1812 Overture, which is incredibly cheesy, but is redeemed by it’s cannon fire. I only know of two pieces with canons in them, which suggests there is rather a shortage.

Obviously, as a composer who feels vaguely compelled to put out an album at short notice, I’m well-positioned to address this dire shortage. Indeed, I can think of no Christmas songs with cannons in them at all.

The other piece I know of with cannons in it is Beethoven’s Wellington’s Victory, which doesn’t wait for the end for the big payout, but has cannons starting early and booming often. I almost hate to admit this, but they get really boring. The more heteronormative* model of music structure seems to work best for explosions. Although, the piece is just terrible throughout, with themes from God Save the [Monarch], Rule Britannia and For He’s a Jolly Good Fellow, it is unbearable. The lack of adequate build-up for the cannon fire is only one of it’s sins – although certainly the one with the greatest grinding, grating duration.

This extremely through analysis of the use of cannons in music implies that extremely bombastic Christmas music is called for.

This isn’t the world we dreamed of, but it’s the world we’ve got.

* Yeah, I went there. I’ve got a critique of Feminine Endings, in which I make the argument that some of it is inspired by TERF attacks on Sandy Stone, but I was advised that this would not be a brilliant career move and I should let the dated past stay there. But, I dunno, some of that text actually is useful – the metaphors are really apt when it comes to things like this piece in particular.

The Election is Over (Let’s Go Back to Postcards)

Democrats control the House now, which is fantastic news! However, most of the assaults on trans rights have been coming straight from Trump, so we need to keep fighting.

In my previous post, I asked people to participate in a post card campaign. This is still ongoing. Please chip in! If you are outside the US, you can print the postcards in A6 format. Or, if you are in the US and going to Kinkos or the like, you might find that 2×2 is the best format.

I’ve had my best luck getting people to put their names down by talking to people and asking them. Response has been overwhelmingly positive. My spouse says that these conversation are more important than the cards themselves. She says that by asking well-meaning liberals to consider trans rights, I’m asking them to think about things they haven’t previously considered, helping them gain empathy and converting them into allies. I’ve certainly seen people go from politely curious to fully engaged after only a very brief chat. As a part of this, I’ve been mostly going to parties and talking to friends of friends. I have not been disclosing during these conversation, but sharing worries about my friends in the US.

Another way to get people to fill these out is to just leave them around. They don’t use normal stamps from the UK, so I come back to collect them. I’ve left them with some text:

Stand up for the trans community in the US!

The Trump administration plans to ‘define transgender people out of existence.’ Put your name on a postcard to let them know that this is unacceptable.

Then either post the card yourself (don’t forget to attach a £1.25 stamp) or drop it in the box here, and we’ll post it for you.

Thank you for your help.

Contact: [My email address]

I’ve done some regrettable shoebox painting for this (I’m lying and telling people it was done by children.) A cereal box is roughly the same dimensions as a sheet of paper and can be tacked to a notice board.

The election was just the beginning of the work we need to do to make the US safe for vulnerable people. This project has been easier than I thought it was going to be and has built meaningful connections. I’ve sent more than 160 postcards since I started. Before this, I spent months sitting in front of my computer fretting at the news. If we all took the time we spent doing that and directed half of it to campaigns like this, we could build a tremendous mass movement to oust Trump, to protect trans rights, migrant rights, and the environment. We are the ones we have been waiting for. We won’t be erased because we will stand up and demand to be seen.

Ways to support trans rights!

There’s a lot of good actions people can do to try to counter the latest Trump attack on trans people. Marching is good. Writing letters to all your local papers is very good. Like really all of them from the regular paper, to the free advertiser to the Bingo Bugle. When the letters get published, forward them to your elected representatives, the White House and the Department of Health and Human Services. You can also write to those people directly. A paper letter carries more weight than an email, especially if you’re writing to somebody on the other side. (Here is the DHHS’s address.)

You probably know some people who are well-meaning allies, but are not going to show up to a march or write any kind of letter. (No hate. Not everybody can do everything.) These folks, however, would be willing to sign a postcard. This is less good than a letter, but it’s better than nothing.

Linked here are two PDFs of postcards. Postcard4x6.pdf is a standard American 4×6 postcard format. PostcardA6.pdf is a metric A6 format postcard (in the size and shape used by every other country on earth). These are grayscale, so printing is relatively cheap.

If you print these out and take them to things, allies who don’t have the spoons for bigger actions will probably be willing to help with this one. If a lot of post starts arriving at DHHS, this will help. I went to a cabaret tonight and got like 50 of these filled out. I’ll take a stack to work tomorrow. I’m going to give a bunch to my friend who is active in a lefty church, so he can pass them out on Sunday. None of these folks would have done anything if I hadn’t asked for this easy thing.

We #WontBeErased

P.S. Also, please don’t forget to vote.