Big Led Panel Incoming

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Perlin noise for the win!

I mentioned a while back that you could get 3 8x8 neopixel panels from Amazon for nine quid. You still can (at least until I’ve bought them all). I’ve started building a 24*8 pixel panel with them. I’ve got the box printed and wired up one panel.

Excuse my soldering

I’ve got it working and it turns out that you can get over 30fps driving all the panels flat out. This means that smooth fades are very doable. The next step is to buy six more panels and see how fast I can drive them in a 16*24 array. The plan is to use separate processor output pins to drive each panel which should make for super-smooth updates too. Such fun.

I’m doing this for an article I’m writing for Raspberry Pi Magazine. The article is about device setting storage. I thought I’d make a device which needs setting storage and it seems to have got a bit out of hand……..

PICO Musicbox

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Say hello to the PICO Musicbox. It contains a Raspberry Pi PICO and uses an M5 Stack Synth module to make the sounds. There’s also an OLED display in the mix along with a rotary encoder. And of course some neopixels. You can see inside the box here. I’ve spent the last couple of days dropping out Circuit Python to make it all work together. If you fancy building one I’ll have the circuit diagram and software available soon, along with the STL files for the case.

PICO MIDI CheeseBox Version 3

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I’ve spent the last day or so writing code. Which has been great fun. The focus of all the effort has been my PICO MIDI Cheesebox which has had something of a makeover. I’ve now got a PCB based version which has an OLED screen in the middle. I’ve added messaging so that you see what you are doing when you press a button. I’ve also added full setting save and restore so that you can create a pattern and store it in the device. And this afternoon I spent some time making an arpeggiator. Such fun. I’ll put it on on GitHub once it works.

Schrodinger's Pico Bluetooth Keyboard

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I’m trying to get Bluetooth working on a Raspberry Pi PICO using MicroPython. I want to make a keyboard that you can pair with a computer and then use without further connection hassles. ChatGPT is being very encouraging and upbeat about the task, but I’m not sure whether it is possible or not. I think I’ll only know that it can be done once I’ve got it working….

Update: I’m pretty sure this is impossible. The aioble library for MicroPython doesn’t support bonding and, although ChatGPT came up with all kinds of fictional ways of making this work, none of them are any good in the real world. Oh well. You learn as much from your failures as you do your successes……

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.

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.

LittleFS filename conventions

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LittleFS is a great way to store files on your PICO or ESP powered embedded system. But it does have its foibles. Particularly when you switch from one platform to another. One thing that can trip you up is that on the ESP8266 and the PICO LittleFS the name method provided by a file object delivers the name of the file in the folder(test) but on the ESP32 LittleFS it delivers the file path to the file (\start\test).

I just discovered this while migrating the Connected Little Box code to the PICO. I’m putting this here so that I can find it again when I hit the same problem in a couple of years time.

PICO Probe in PlatformIO

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I probably shouldn’t be quite so surprised when something just works, but I must admit to being slightly shocked when I managed to deploy a C++ application into a PICO using the Raspberry Pi debug probe the first time I tried.

Debugging just works too. I’ve now got a new PC (replacing my 8 year old one with something a bit more sprightly) and the build and deploy cycle is now pleasingly short. This really is a great way to work. I’ve now got the Connected Little Boxes core running on a PICO as well as ESP32 and ESP8266 and I’ve re-factored the code so that it is now easy to manage the feature set assembled into the code. This makes it much easier to remove features that won’t fit on the ESP8266. Great fun.

Don't touch that button!

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This is what the Rabbit thought of our TV while we watched the Olympics opening ceremony

Made a little menu system for the leaky camera system today. It lets you bind Python methods to button presses and seems to work quite well. I’m using the lovely Pico Display from Pimoroni. I’ve got one of the very original ones, which doesn’t seem to work with their current Button code. It took me a while to discover this, what with my policy of always assuming that if something doesn’t work it is my fault. Anyhoo, it now works and will be going on GitHub soon.

Making a Leaky Camera

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The PICO on the side of the camera controls the brightness and colour of the led lights

What kind of an idiot puts lights inside a camera? Er, this kind of idiot (and also Fuji Film with their Instax Mini 99). I was converting another Polaroid Land camera to use Instax film (it’s a thing - believe me) and I wondered what would happen if I put some leds inside and exposed the film a bit with them. Well, today I built the first version. I’m using a PICO with a little LCD panel to control a row of Neopixels inside the camera. I’m not sure how well this will work, and what level of exposure is required, but I’m going to enjoy finding out.

Pixelbot PCBs at the May 1st Hardware Meetup

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The coloured pins make it much easier to see what each connection does

The Hull Pixelbot is going from strength to strength. The original device was powered by an Arduino Uno running a thing we call HullOS. Late last year we ported HullOS to the Raspberry Pi Pico. To make it easier to connect (and to add some interesting new options) Brian has designed a PCB that provides a proper power supply for the PICO and exposes all the connectors for motors and sensors. We’ve also got space for an OLED screen and a couple of push buttons.

This is a major development for Pixelbot. It means that we can expand Python-Ish (or maybe even replace it with “real” Python). It certainly gives us a lot more options when building robots.

Brian used a tiny hotplate to install all the surface mount components. We’ll have the hotplate and some components at the next Hardware Meetup so you can actually watch a circuit board being soldered.

Person Sensor Powered Paparazzi

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I’ve found a use for my broken camera collection. I’m going to create a “paparazzi machine” using a person sensor from Useful Sensors. The person sensor is a tiny camera with a processor which you connect to your microcontroller using i2c. It tells the number and position of faces that it can see in the frame.

The plan is to take one of my slightly less broken cameras (one with working lens movement) and put it on a mount that lets it move towards a face and then trigger when it sees someone in front of the camera. I’m going to use a Raspberry Pi PICO to control it. Should be fun.

Stop your Circuit Python devices showing up as a disk drive

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Click the image to watch the video….

Got a message from Chris over on YouTube. He’s built my PICO Chord Keyboard design (it worked - phew) and he was wondering if there was a way to stop it appearing as a storage device each time it is plugged in. This is a very useful feature of Circuit Python - it’s how you get the program code onto the device - but it can be irritating, as well as giving folks access to your device that you might not want. I sent a reply and then I thought I’d share it on the blog:

You can stop the device appearing as a usb storage by editing the boot.py file (or adding one if it is not there) on the device. Put the following in there: 

import usb_cdc
import board

# Disable USB mass storage
storage.disable_usb_drive()

This should stop the device appearing as a file-store. But remember that if you do this it will be tricky to update the code in the device. You'd have to wipe the EEPROM to get your PICO back to a state when you can change the files.

More details here: https://docs.circuitpython.org/en/latest/shared-bindings/storage/index.html

Effortless Debugging with Your Pico Probe: No More Sudo!

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Hey there, Raspberry Pi enthusiasts! Are you tired of summoning sudo every time you need to commune with your Pico debug probe? Fear not! Today, we're delving into a nifty trick to make your Pico probe obedient without the superuser incantations. And for those of you using Visual Studio Code, this trick is a game-changer.

Why Bid Farewell to sudo?

Summoning sudo for debugging is like wearing a full suit to a casual brunch; it's overkill and can be risky. Moreover, when you're using elegant tools like Visual Studio Code, running the debugger as a superuser inside the tool is a bit tricky. Let's simplify this, shall we?

The Power of udev Rules:

In the Linux realm, udev rules are like spells that control how the system interacts with various devices. By crafting a specific udev rule, we can grant ourselves permission to access the Pico debug probe without escalating our privileges to the superuser level.

Crafting the Universal Pico Probe Rule:

Most Pico debug probes share the same Vendor and Product IDs, so we can usually use a standard rule for all. Here's how to do it:

The Magic Numbers: For the Pico debug probe, the typical IDs are: Vendor ID 2e8a and Product ID 000c. We'll use these in our rule.

Creating Your Rule: Head over to /etc/udev/rules.d/ and conjure a new file called 99-pico-debug-probe.rules Sprinkle the following line into it:

SUBSYSTEM=="usb", ATTRS{idVendor}=="2e8a", ATTRS{idProduct}=="000c", MODE="0666"

This incantation essentially tells your system, "Hey, let everyone read and write to this device, will you?"

Enforcing the Rule: To make the rule take effect, use this spell: 

sudo udevadm control --reload-rules && sudo udevadm trigger


What If My Device Is Different?

Got a different device? No problem! Plug it in, run lsusb, and look for the ID format VendorID:ProductID. Use these values to create a custom rule.

Post-Reboot Harmony:

Your new rule is like a loyal house-elf, diligently working after every reboot, ensuring smooth, sudo-free access to your debug probe.

Conclusion:

And there you have it! A simple yet elegant solution to make your debugging sessions with Raspberry Pi Pico as smooth as butter. No more sudo, no more hassle, especially when you're working in sophisticated environments like Visual Studio Code.

Happy debugging, and may your code be bug-free!

Author’s note: I didn’t write this. ChatGPT did. I worked with ChatGPT to solve my problem and then asked it to write a blog post about the solution “In the style of Rob Miles”. I’m quite proud of this, although I didn’t do much of the work….

PICO Powered Pixelbot now with Wi-Fi programming

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Just plug your Pixelbot into your computer to set up the network

The latest version of the Raspberry Pi PICO Powered Pixelbot (I love a bit of alliteration) now supports Wi-Fi programming. You can connect your robot to your local network and then use a web interface to create and deploy programs into the robot. You can find all the details, plus the images you need to put into your PICO-W here.

Too much voltage is bad for you

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the first PICO powered Pixelbot

I’ve not made a brand-new Hull Pixelbot for a while. Today I made a new one which is powered by a Raspberry Pi PICO. I usually power the robot from four (or sometimes five) AA batteries. This gets me around 6 volts. I did that today with the new robot and it failed to work. It turns out that the Raspberry Pi doesn’t like voltages much higher than 6 volts, and shows its displeasure by not working. I had scrabble around to find a set of “slightly worn” batteries to get it going.