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Bit Board & micro:bit Powered Step Sequencer

The first guide I published for Brown Dog Gadgets was a step sequencer using their Arduino-compatible Robotics Board back in April 2020. You may also remember my WMSE sculpture that was a step sequencer, and I never did a write-up on it, but I also built a step sequencer for an interactive museum exhibit years ago, which was kid-tough and focused on sequencing as a form of programming.

Anyway, since it was nearly a year from the first Crazy Circuits step sequencer I think I should revisit it as a micro:bit project. So here’s a guide to building a Bit Board & micro:bit Powered Step Sequencer.

The code was written using Microsoft MakeCode for micro:bit, a block-based programming environment, which also supports Javascript and Python in text modes. It’s been interesting working in a block-based programming system, and I’ve gotten used to it in the past six months. I do really like the fact that you can toggle between block view and text view.

I’ve got a lot more micro:bit projects I’ve worked on in recent months, which you can check out in the Brown Dog Gadgets Project Database.

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Slide Advance Alert System (with MIDI)

Here’s a project I did a while ago, but never documented here… At Brown Dog Gadgets we do a lot of video streaming for workshops, and our setup includes one person on camera and another person as the producer who runs the software, monitors the chat window, and does the camera switching and advances the slides.

We started talking about an easy way for the person on camera to let the producer know when to advance to the next slide without having to say “Next slide, please” 20 times each session. Our video software can easily control the slides by using the left and right arrow keys, so we thought about just making a small USB controller the presenter could use to send those key commands, but that only works if the video streaming software has focus as the frontmost application, and since we’re running multiple pieces of presenting software as well as a browser we can’t rely on key commands to work.

So what I came up with is a simple controller that sends MIDI signals to a custom application that plays a sound which the producer can hear through their headphones, and know that it’s time to change the slide. (The application also has a small window that displays “Waiting…”, “Forward”, or “Back” depending on the state of the controls.)

The great thing about MIDI is that it doesn’t rely on a specific application being frontmost… Yes, we could have used serial communications, but we’d need to then select the correct serial port, which changes depending on which USB port you use, hubs, computer, etc.

We’ve got a guide in the Brown Dog Gadgets Project system, and we also dropped it onto Instructables if you want your own Slide Advancement Alerting Device.

This is a niche solution to a niche problem, but that seems to be what I’m good at, so I’m just gonna go with it.

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Valentine’s Day Cards

I cranked out a bunch of paper circuit Valentine’s Day Cards for Brown Dog Gadgets. These can all be made with the Paper Circuits Kit which features conductive Maker Tape, tons of LEDs, batteries, and other supplies. Add all the free templates and resources and you’ve got yourself a good time.

Heart Friend Valentine’s Card

I LOVE U Valentine’s Card

Picture You and Me Together Valentine’s Card

The Cake is a Lie Valentine’s Card

You’ve Got Mail Valentine’s Card

Human Heart Valentine’s Card

You’re Aces Valentine’s Card

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micro:bit Powered Xylophone

A recent fun project over at Brown Dog Gadgets is this automated xylophone controlled with a micro:bit… Check out the build guide.

Full instructions including code and some helpful tips on choosing a (toy) xylophone that will work for this project. (There’s maths and angles involved.) We’re basically controlling two servos to move a mallet left and right and then down (and back up) to strike a bar.

You can control it by playing it like a keyboard, just press the buttons, or you can program and store songs for automated playback later.

The (toy) xylophone isn’t really tuned very well, so we may be working on a larger project that uses a larger instrument. Also of note is the fact that the micro:bit out of the box can only handle three servos (without extra hardware) so we might switch to another board for the next iteration.

As usual, and since we’re using LEGO compatible servos, there are LEGO bits involved, which made building things quick and easy. (And don’t worry if you don’t have the needed LEGO parts on-hand, we’ve listed the parts we used and linked to where you can get them for cheap.)

Here are a few slightly out of tune songs…



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Capacitive Touch on the micro:bit

Note: This post describes a hack to use capacitive touch on the micro:bit V1.5 but shortly after doing this, the micro:bit V2 came out, featuring real capacitive touch.

Out of the box the micro:bit has three touch pins which relies on a person touching not only the pin they want to trigger, but also to touch ground. Typically a person holds or touches something connected to ground, and then with their other hand touches one of the touch pins. This is how the Makey Makey works as well. It’s like capacitive touch (or capacitive sensing) but it’s not exactly. [It’s resistive touch.]

With a bit of experimentation we found that you can do capacitive touch on the micro:bit (sort of) so we wrote up a guide how to do it for the Brown Dog Gadgets Project Database called Capacitive Touch.

Two things to note about this one, first we are using the pins for analog input and while there are three more pins that do analog input on the micro:bit we found their performance to be a bit more unreliable than pins 0, 1, and 2. Of course since this is really just a hack, don’t let that stop you from using them. Second, there is no calibration done on the pins. For one of our Invention Board projects using capacitive touch we do a calibration at start so the pins know what is touched and what is not touched, as it can often change depending on the environment. The code we present does no calibration, but we’ll probably add that in the future.

As usual we’re using Maker Tape along with a LEGO baseplate and a Bit Board. (If you want a Bit Board to go with your micro:bit, we’ve got a Kickstarter campaign running now.) Capacitive touch is a lot of fun, and I’ve used it for many projects over the years. And yes, you can certainly incorporate other objects or surfaces besides Maker Tape.