Hardware Meetup Wednesday 10th December

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We’re having a Hardware Meetup in Hull Makerspace (top floor of Hull Central Library) starting at 5:00pm on Wednesday evening (10th December). You can arrive later if you like, but don’t arrive after 7:00pm because that’s when library shuts and we all go for dinner.

There’s a prize for whoever brings along the best Christmas Lights display. And everyone gets a mince pie and a chocolate. Please note that I’m not just doing this because I’ve found a great long string of neopixels. Oh no.

Printing Slow

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..now with the words “half” and “Quarter”

I’ve been printing wordsearch clocks again. As you do. The first few prints were spectacularly unsuccessful, which was a surprise as my Bambu printer is usually super reliable. The problem was that the first layer that is printed is the white letters. These are very thin and I’ve always found that white filament tends to not stick as well as other colours. The result was a couple of very messy prints that I had to abandon. So, I tried slowing things down a bit.

This is the print speed menu in Bambu studio. You can change printing speed by height, so that the first few layers of a print can be printed very slowly giving the filament time to stick to the bed. I just print the first 4mm of the model at the low speed, but because this is one of the more complicated bits it added over an hour to the print time. But it also worked, which is nice. So now I can make white and black and black and white wordsearches.

Cleaning Battery Connections

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I don’t know why I’m giving out camera repair tips. After all, the camera I’m mending is still not working properly. I’ve narrowed the problem down to one of the five transistors it contains, or perhaps one of the eight switches. Time will tell.

Anyhoo, if you have anything which contains a hard to access battery connection (perhaps at the bottom of a battery holder) you just Blu-tak a small piece of sandpaper to the end of a battery and then push the battery into the holder and rotate it a bit to clean off the connections. Works a treat (but will not fix any other electrical problems that you might have).

Blu-tak is actually really useful for mending stuff. You can use it to hold things on the bench, stick screws to the end of the screwdriver for tricky to access fixings, and also hold things in place while you assemble them.

Schrodinger's Revenge

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Yesterday I was waiting for a battery to arrive so that I could discover whether I had a working camera (yay!) or a broken one (boo!). Of course, just because there are two outcomes doesn’t make them both equally likely, so I should have been prepared for brokenness. Which is what I got. Wah. So it was off with the top and…

It’s probably one of these wires…

A bit of experimentation with a multi-meter left me thinking that no power was getting to the system.

…or more likely this one.

One problem with old cameras is that chemicals leak out of the battery and corrode connections, which is what has happened here. So all I have to do is find the battery terminal and solder this wire back on. Or, replace the wire completely - which is what I ended up doing. So now, with the battery check light showing a happy green, I’d fixed the camera, right?

Wrong. The metering was all broken and the shutter didn’t open and close how it should. Turns out that my camera has succumbed to “The Pad of Death”. This is a thing with Yashica Electro 35 cameras. The shutter mechanism uses a tiny foam pad to transfer movement from one lever to another. But, plastic foam being what it is, after a while it turns to dust. No pad, no movement, broken camera.

There should be a foam pad where that pink yuccky stuff is

I had great fun fixing this. If by “great fun” you mean “nearly went insane rolling up small pads of tape and then trying to fit them into the slot between the two parts”. If it breaks again the camera will end up being a “display piece”. Or going on eBay as “sold for parts”.

Newly fitted pad. I hope the glue holds…

Anyhoo, I prevailed and now the meter is doing an impression of something that might be working. I’ll to some proper testing tomorrow, for now I’m happy that I get longer clicks with darker subjects. To be honest (why on earth to people say that - it’s like saying “I was thinking of telling you a lie, but I’ve changed my mind”) I don’t mind if the camera is not quite right yet. I’ve quite enjoyed fiddling with it - pad of death not withstanding - and I’ve gained a lot of respect for the people who designed and made this marvel of mechanics and early solid state electronics. I’m sure they didn’t expect folks to still be trying to use them 50 years after manufacture. It’s a tribute to them that they still mostly work.

Making Stuff Tech Session

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I used the converted polaroid camera to take some audience pictures but the ambient light was too strong, so we got a lot of blur. I also added a red cast which you can just about see.

We had a lot of fun at the Tech Session tonight. Rory did a splendid talk on testing, which put software testing into a properly useful context, and then I talked for 45 minutes on the joy of making stuff and what I’ve been up to lately.

For anyone who wants to know what I was on about, I’ll record a screencast (with all of the demos) later this week. You can find out about upcoming Tech Sessions here.

In the Money?

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I got a strange email this evening from a bunch of lawyers. It’s about the Anthropic Copyright Settlement. This is a class action brought on behalf of authors whose work allegedly appeared in a couple of allegedly pirate datasets that were allegedly used by Anthropic to train their AI systems. Allegedly. Anyhoo, I searched their database and 7 of my books were identified…

The settlement amount was 1.5 Billion dollars, but individual authors only get a tiny percentage of this. It’s nice to see some action being taken on behalf of creatives who have had their work used in this way but I reckon we still have a long way to go. Or at least, we should have. Now I get to fill in a form and wait until the end of April next year for the next phase of the process. I just hope I get enough to buy a camera…..

Colour Film Processing Fun

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If you are wondering what is special about the picture above, its that I actually developed it myself. I’ve done a lot of black and white processing but I’ve always avoided colour because it just sounds too scary. But now you can get chemicals which only need two baths. This makes working with colour very like working with black and white, where you usually need dip the film in developer and fixer.

The only other problem with colour processing is that you need to keep the chemicals at a specific temperature; in our case 35 degrees centigrade. We did this by using a new fangled cooking tool called a “sous vide” which heats and circulates water around a bath we made from a plastic box. All we had to do was drop the bottles of developer and “blix” (bleach and fixer) into the bath and leave them there for a while, and then keep the developing tank in the bath while the film was being processed.

The whole thing went very well; once we’d mixed up the chemicals which took a little while. In all we developed four films. The chemicals should be good for another 8, and we might be able to develop even more if we increase the development time still further. I can’t really tell the difference between our negatives and ones from “proper” film processing places. By doing four films we’ve kind of broken even on the cost of the chemicals against sending the fillm away, the next few should see us moving into proper savings. Great fun. Just remember to wear gloves and work in a well-ventilated area.

Birmingham Comicon

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You will practice your saxophone

We went to Birmingham Comicon today. It was great fun. The only thing I bought at the show was a year’s supply of saxophone lessons, and they weren’t actually on sale there, that was just a subscription I’d forgot to cancel that automatically renewed itself while I was in Birmingham. I hate it when they do that with no warning. But some good will come of this. I’m going to start practicing the saxophone again…

I took the big heavy camera too with a huge lens too. This proved very bad at getting focus, but I did get a few shots.

Hardware Meetup with lots of Python

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Please note that the time is not six past sixteen. And always wear shoes.

We had a very pleasant evening at the Hardware Meetup tonight. I was showing off the Connected Little Boxes Micro Python framework which is powering a couple of clocks that I’ve made. They worked great right up to the point where the input parser broke. Oh well.

Then it was off for dinner, which was great. Conversation turned to a study which has discovered that the brain has five ‘eras’ with one (a precipitous decline in the amount of “white matter” - whatever that means) starting at around my age. Then, when I got back to my car I discovered that I’d left my backpack in the restaurant. Perhaps the study is onto something….

Significant Other Charms

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These are the finished versions and they’ve printed quite well. The idea is that you have one, and you give your significant other, er, the other. Then, when you meet up you can fit them together (they do fit rather well). Each pair is completely unique (unless you print lots of them I suppose) and symbolises the uniqueness of whatever you think is unique about whatever your relationship is. Oh the romance of it all. I’m putting together some examples of writing Python code inside the FreeCAD design tool, and the charms are one of them. Another is my “Little City”.

Not bad for around 100 lines of code. The examples will all be going on GitHub soon.

Lytro Light Field Camera

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this is really what the cameras looks like

This little camera is like no other. Except perhaps the other Lytro camera (of which more later). It takes photographs as “light fields”. Rather than focusing an mage on a sensor, the Lytro uses tiny “micro lenses” in front of the sensor to create a pattern describing the light rays arriving at each point in the picture. Pictures are created by processing the light field pattern, which means that you can do funky things like focus a picture after you have taken it. You can even make videos of the focus changing…

The video above was created from a single Lytro picture. You make these using the Lytro application which you can download from here. You can even get this to run on Windows 11.

You can pick up Lytro cameras for not much money. I got one and the pictures and performance were rubbish. But then I upgraded the software to the most recent version and things got significantly better. If you get one and want to upgrade it you need to use the Lytro application which tries to fetch the upgrade firmware from a long dead Lytro site. But you can get round this by patching a code file to redirect update requests to a site that does have the required files. I did this and felt very “hackery”. You can find out more details here.

Look Ma! I’m patching a binary!

Light Field Photography was a fantastic idea which didn’t survive the collision with reality. The focus party trick is achieved at the expense of a huge downgrade in quality and the arrival of a whole bunch of image artefacts. That said, I quite like the pictures the camera makes, and you don’t need 20 megapixels for every photograph you take.

Lytro survived the indifferent reception of their first model to make another camera which had a much higher performance sensor and processor and produced much better pictures, but ultimately it was killed by smartphones providing the same kind of focus trickery by using depth cameras and lots of image processing. That said, it is fun to play with and if you are a camera nerd you could do worse that get one. You can find out more about the camera here.

MicroPython Connected Little Boxes

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All new lego logo

I’ve just released the latest incarnation of Connected Little Boxes. I’m in the process of converting the original C based system into MicroPython. I’ve got enough of it working to make it useful and now I’m looking for people to break it and tell me it’s rubbish.

You can find it here. If you have a spare Raspberry Pi PICO you might like to give it a spin.

Holey Stupid

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I’ve got a new desk. Gone are the bright red Ikea ones that weighed substantially less than the things we put on them. Now I have a big strong counter which hopefully won’t move much when I strap a steering wheel to it.

Anyhoo, I wanted some holes for cables to go through. And I also fancied the device above, which sets a rather useful mains socket and some powered usb ports into the desk. I discovered that these are 80mm diameter. So I asked for some holes which were 80mm diameter. Big mistake. Turns out that two things which are exactly the same size don’t fit together properly. The result you see above is the result of a bunch of frantic extra sanding on my part…