Watch Wednesday

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Talking of things to watch while the football is on (and there really is a thing in it too) you might like to take a look at Wednesday. It’s an offspring of the Adams Family franchise which you can find on Netflix. Some of the episodes are directed by Tim Burton and they seem to have spent a lot of money on this. The early episodes are really good with some great sardonic humour and lovely set pieces. The later ones turn a bit “Harry Potterish” but the whole thing is carried along by the acting and production. Well worth a look.

Heading to Driffield

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David asked me if I fancied giving a talk to some sixth formers at Driffield. A chance to perform in front of an interested audience? Count me in. I took along a few toys, the trombone controller and my cut-price laptop. Much fun was had. The students were great. Lots of lovely questions (although one person did ask how tall I am - and after I had specifically told them not to do that). Kids eh?

I love telling the tale of embedded development. This is the best time ever to be doing it. Making stuff has never been so easy, so cheap, and so useful for building up your personal brand. I’m looking forward to going back some time in the future to see what they have been making.

David had brought in some trombones for me to look at, including the super shiny one above. It was nice to be able to compare the action of my sensor with something real.

Breath detecting with an environmental sensor

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Turns you can do it. I’ve been wondering how I can detect people blowing into a trombone. As you do. A microphone is one possibility, but that involves analogue to digital conversion and sound processing and stuff. And owning a suitable microphone. I do however have a bunch of BMP20 environmental sensors. These contain an air pressure detector. They are supposed to be used for weather data and determining your height above sea level. Would it work for breath?

The answer is yes. If you put a sensor in a closed box (see above) and then blow into the box you can make a detectable difference to the pressure inside. All you have to do is sample the air pressure at the start and then look for a change of around 5 or so during gameplay.

It worked really well for a while. Then the BMP280 stopped working. I had a look in the box and discovered why. It was rather disgusting. Breathing into a box produces not just air, but a lot of water vapour too. The inside of the box and the sensor itself was covered in what you could politely call “dew” but was actually something slightly different. Trombones have a “spit valve” on one end to release all the stuff that accumulates. I’m happy to have proved the principle. I guess I could engineer some baffles or a waterproof membrane over the sensor to keep it dry, but the thought has occurred that in these virus laden times, passing around some thing that you take in turns to breath into might not be a great idea.

So I’m building a version of the controller that uses buttons rather than breathing.

Hello Harrogate

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Yesterday we went to Harrogate for the Knitting and Stitching Show. That is, some people in my party did that part. I’m not into knitting or stitching just yet. I went round Harrogate looking for things to photograph using the Mint RF70 that I’d taken with me. Harrogate was doing its best to be interesting, what with Transformers wandering around and inflatable Thunderbirds vehicles. The weather really wasn’t helping much though. The rain was pretty much constant. I wasn’t the only person there wearing waterproof trousers.

However, we all had a great time. Wool was bought, embroidery was done and we had a really nice lunch at the Fat Badger (strongly recommended). Then I went round one of the many lovely parks near the town centre and managed to grab a few more shots before the heavens opened again. Great day.

Add graphs to your IoT projects

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I’m building a trombone controller. And why not? I’m using a distance sensor to track the position of the trombone slide. The output is a bit noisy. But how noisy? A graph would help, but how do I get that? Very easily as it turns out. I just added a print statement to my Circuit Python application:

print(raw,",",average)

This prints out my raw and averaged values with a comma between them. Then I used Thonny to run the program in the trombone for a while and moved the slider. Then I stopped the program, copied the output of the terminal window into notepad and saved it with the file extension “.csv”. (Comma separated values).

Then I opened the file with Excel (other spreadsheets are available) and made the above graph. It shows how my rolling average (the red trace) cleans up a lot of noise but makes the values lag slightly (look at the how the red trace rises slightly after the blue one).

If you aren’t sure what your signals look like this is a very easy way to do it. The Arduino IDE has a graphing feature built in that I’ve used once or twice, but there’s nothing like dropping your values into a proper spreadsheet for analysis. And it is very easy to do using the magic of cut and paste.

When in doubt, bring the sun with you

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A while back I took some instant pictures that were a bit compromised by colour balance of artificial light. I decided that one way to fix this was to bring along a light of my own. A quick search of ebay found me a Hannimex PRO550 along with mounting plate for around 10 quids. I’m going to have to modify the flash cable or find an adapter (the RF70 has a funky 2.5mm socket) but if I use this flash I don’t think I’ll need to worry about artificial light. Plus, as an outfit it looks awesome.

I just hope I don’t blind any of the subjects or give them a suntan they don’t want…..

See How They Run is a really good film

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We watched See How They Run last night. This is a lovely little movie. Lots of laugh out loud moments - at least for me. I think it leans rather too heavily on real life with its use of a real play and a real author to hang the plot on. I reckon it would have worked better if it was all made up. But that doesn’t take anything away from some lovely stuff. I hope they make some more of these.

Comicon with Instant Pictures

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Well, that was …interesting. Comicon was wonderful. Made even better because we travelled down yesterday and got to the exhibition fresh, rather than after a 120 mile drive. I took a bunch of pictures with my new camera and, as you can see above, results were mixed. Exposure is a challenge and because I wasn’t using a flash the white balance for the film wasn’t quite right.

White balance with digital cameras is not a thing. The camera figures out the colour temperature of the scene and adjusts for it. White balance with a film camera is a thing. Because it turns out that the sun is hotter than electric lights and puts out a lot more blue light. Inside you get a warmer light if you use bulbs with filaments in them (like they all used to be) or weird light if you use modern energy saving bulbs. Film is normally manufactured for outdoor use, so when you use it inside the white balance moves about a bit and you get colour casts on the picture. So, if the pictures above look as if they have strange colours, that’s why. The pictures above also look a bit blurred and dark. I can’t blame that on the film, that is down to me learning my way around the camera.

The funny thing about instant cameras is that you seem to give away your best pictures. I took a shot of a chap who sold me something (he wanted to know what the camera did). The picture came out really well so I gave it to him. He was really happy with that, which I think is what things like photography are all about.

Enter the Mint RF70

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The bloke on the left is asking “What happened to you? Was it drink, drugs or crazy living?”. The bloke on the is replying. “Nothing like that. Instant photography”.

I’m getting my hands on a Mint RF70 camera. This will be even more expensive to feed than the Mint TL70 I got a while back and probably as hard to use. Better start looking for comfortable park benches now.

Dominion on the Steam Deck works rather well

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The Dominion card game has kind of taken over our Tuesday game nights. The great thing about it is that by using different cards each week you can get a totally different game experience. I’ve started using my Steam Deck to play it (you can find the game on Steam). It works rather well. Probably overkill, but it works for me. I like having a Dominon game on the go when watching naff telly. Today I nearly managed beat the medium AI opponent, which was rather pleasing.

Trombone Controller Fail

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The beautiful distance sensor box that I made yesterday only has one problem. It just doesn’t work. When you put the tube over the distance sensor you get a fixed distance reading. I think it is something to do with reflection off the end of the pipe. Above you can see what happens to the light on the sensor, perhaps something similar is happening to the distance signal.

Oh well. Perhaps I should have tested this approach before I designed and printed the box, but I was concerned that to test the sensor I really had to have it mounted and aligned just right, and a proper box was the best way to do it. I just have to move the sensor outside the pipe and create a target. And anyway, it’s only a failure if you didn’t learn anything from it.