Surface Mount Soldering

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Heating up Nicely

I’m making some more Cheesebox synthesizers. I’ve got a plan to make a monstrous device with pixel rings, grids and speakers. For the insides I’m assembling some circuit boards using surface mount technology. I’ve got a couple working so far, with a third just cooling down. These are the things I have learned today:

  • Surface mounting is very doable as long as you have the right stuff:

    • A little hotplate

    • Solder paste that melts at a low temperature in a syrninge

    • Some right angle tweezers

    • A trigger thing for your solder syringe. This makes it much easier to get exactly the right amount of solder paste on each pad.

    • No feeling in the tips of your fingers (you already have this if you have previously built and maintained a 3D printer)

  • When you are squirting solder paste onto a pad, lift the needle up vertically before moving it to the left or right towards the next pad. This will give you a good looking vertical “blob”. It’s a bit like icing a cake. Not that I’ve iced many cakes to be honest.

  • I set the heated bed temperature to 170 degrees, with my solder specified as melting at 128. This seemed to work OK for my oven. When the hotplate hit 170 degrees I turned it off. I then used a piece of card to slide the board off the hotplate onto card. A bit like how you move pizzas around.

  • Watching the solder melt and surface tension pull things into position is great. I put one of the leds in the wrong way round and it was fun to watch it try to rotate into the right position. It was an easy fix. I just picked the led up and dropped it back down in the right orientation.

  • The best way to find out if a circuit board is hot is not to touch it with your fingers.

YOu adjust the screw as the plunger goes into the syrninge

I bought the yellow trigger assembly on AliExpress. It is much easier to use than the plunger.

Tomorrow I’m going to put a couple of boards into cases and start working on the code.

Return of the PICO MIDI CheeseBox

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this passes for a tidy desktop in my house

I invented the PICO Midi Cheesebox a while back. It was great fun to make. It performs as a mini-sequencer keyboard, powered by a PICO and using a 12 pixel ring and 12 buttons to control it. A Python program inside gives you a three track sequencer with keyboard input.

The cheesebox is designed to be used as a MIDI input device, it doesn’t have any sound generation built-in. It works really well with my Chocolate Synthbox which contains a Raspberry Pi running a Pure Data synthesizer program.

Then, just before Christmas, Brian put me onto a new device from M5Stack. The Unit Synth contains an SAM2695 audio synthesizer and responds to General Midi commands to make sounds via a tiny built in speaker. I got one to play with and one as a present for number one son. It works really well, although the speaker is a bit weedy.

I did some more digging and discovered the Unit MIDI which contains the same synthesizer chip, replaces the speaker with a 3.5mm stereo jack socket and adds a couple of proper MIDI connections. So I got one of those as well. the aim now is to make a super-cheesebox which contains a Unit MIDI and some proper speakers. I’ve got the cheesebox controlling the synth, next thing to do is package it and then tidy up the software a bit.

The OLED screen doesn’t work at the moment.

I’m going to be using one of the CheeseBox PCBs I had made a while back, fitted into a newly designed case. This means more surface mounting shenanigans. Such fun.

Minox Photos of Hull University

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Last week I sent MSHobbies film processing a cannister containing a strip of Kodak Ultramax colour film I’d run through my tiny Minox camera. The film preparation process had been a bit of a faff. I had to slice some film from a 35mm cassette into 9mm wide strips and then load them into Minox cassettes that fit inside the camera.

The film I used is probably a bit too fast for the lighting conditions (which is why things look a bit over exposed and washed out here and there) but I’m very happy with the results.

Camera with glasses for scale

I’m looking forward to taking the camera around with me and grabbing some more shots in the future. If you fancy the genuine film look from a proper design classic you could do worse than get hold of one of these cameras and have a play. If you don’t fancy loading and unloading your own cassettes you get pre-loaded ones which can be sent off for processing and reloaded. Great fun.

Agile Octopus Display Updates

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When the price is negative it means you are being paid to use electricity

New Year, new you. Newly broken Agile Octopus Display. We’ve been on the Octopus Agile Tariff for a while now. The price of our electricity changes every half hour. If we plan our power use a bit we can save money. Every now and then, when the weather is warm and windy, we can even get paid for using electricity, as you can see above. We’re not saving a huge amount of money (although sometimes we get to drive the car for free) but we are having fun.

To make managing our power use a bit easier I made a little display that lives in the kitchen. It gives you the current price and future price trend for the day. It’s been working fine for ages but in the new year it broke. I assumed it was something in my code (it usually is) but this time the fault is down to Octopus re-arranging their tariffs and changing the web address of the service that dishes out the price values.

I’ve made a new version of the tariff display code which uses the updated links. I’ve also taken the opportunity to tidy a few things up. You can find out more about it here.

Using an Old Printer on Windows 11

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A while ago I got a cheap colour printer. I’ve been using it on Windows 10 and it works a treat, but on Windows 11 things are a little bit more complicated. You can install the printer drivers that you can find here and you can print OK. But if you reboot your computer the drivers might vanish (it’s happened to me) and you have to install them again.

Worse, sometimes the install fails with an error about things already being in use. I asked ChatGPT for help and it came up with this which worked for me.

Thank Goodness You're Here is wonderful

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Thank Goodness You’re Here (TGYH) is a breath of fresh air in video game land. It is deeply silly, very funny, easy to play and doesn’t take too long. Some video games create dystopian worlds full of strange creatures with outlandish behaviours. TGYH does this, but in a depressed town in the north of England. The voice acting, artwork and animation are all wonderful. And that’s just the nice things beginning with A. Mostly.

I simply cannot say enough nice things about this game. And the fact that it is now on sale makes it even more irresistible.

Being bold is harder that it used to be

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One of the more horrible things about modern software is the way that it changes when you are not looking. Yesterday my installation of Visual Studio Code completely vanished (probably due to a broken upgrade) and today I discovered that CTRL+B in Word doesn’t make things bold any more. It is now CTRL+N. Apparently this is a thing.

The way I see it - if the change is deliberate the system should display a helpful message (and perhaps an explanation) when you press CTRL+B. And if the change is a mistake then I worry for Microsoft Office.

Reset a PICO into USB boot drive mode from C++

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The Raspberry Pi PICO is lovely. But it does have a few quirks. One of them is that if you want to load new firmware into the device you usually have to hold down the BOOTSEL button during power up to force the PICO to boot into a filestore mode where you can download the new code into it. This works OK, but it becomes a pain if you put your PICO into a nice box which covers the BOOTSEL switch. To get round this I’ve added a command to Connected Little Boxes which causes the PICO to reboot into filestore mode. Below is the function that implements the “upgrade” command: 

void doFirmwareUpgradeReset(char *commandLine)
{
    alwaysDisplayMessage("Booting into USB drive mode for firmware update...");
    saveSettings();
    delay(2000);
    reset_usb_boot(1, 0);
}

The interesting thing here is the reset_usb_boot(1,0) function call which causes the PICO to boot into filestore mode. I can now make a call of doFirmwareUpgradeReset when I want to do this.

UNO No Mercy is a Horrible Game - I love it

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The people behind the Uno game have a neat line in making new, different versions of their core product. A while back I had a go at Uno Flip, which I thought was a nice twist on the game. Uno No Mercy is not a nice twist on the game. It is thoroughly nasty. You can do horrible things to your opponents. But, better yet, those horrible things can rebound with hilarious results. We played it today.

You normally win an Uno game by getting rid of all your cards. But in “No Mercy” this is close to impossible. Instead you have to resort to destroying your opponents by increasing their hand size to more than 25 cards, at which point they are kicked out. When you find that there are “pick up 10” cards, and that card pickups can be passed on and increased from player to player, you get an idea of the kind of mayhem that you can get. In the end I won, thanks to some very helpful advice from the other players. But I want to have another go. Great fun, but you might not finish smiling.

More camera nostalgia

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This blog might be turning into an old camera blog. Which is fine by me. Number one son has dug out my old Canon PowerShot G9 which I must have given him a while back.

If you are looking fora neat backdrop, I reckon this will do

This camera went with me to Egypt in 2009 and took a bunch of pictures, including the one above.

Another of my favourite pictures

We don’t have any batteries or a charger for the camera, but those are easy problems to solve. I’m looking forward to seeing how it stacks up against my more modern cameras.

Microsoft Flight Sim 2024 is now very good

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Photographing stonehenge

We were all very excited when the new version of Microsoft Flight Sim launched last month. We were a bit less excited when it failed to run on the day of release and even less excited when it still wasn’t working after a few days. But now it has settled down and turned into something really very good. The missions are great. We had a lot of fun trying to land on an oil rig and then taking pictures.

It runs well on the Xbox and really well on a proper PC. Well worth a look if you’ve flown before, and if you haven’t the new career mode, with chatty passengers and a chance to take flying lessons at an airport near your house, is rather splendid.