Tiny2040 + Old Valve + NeoPixel

Phil is working away on the “Oop Tree” on the Pico, but is getting into “slow progress” with getting to grips with the implementation of how the tree will be affected by various inputs (water, food, light).

So as a “quick show n tell” – he’s put together a quick project using a #pimoroni #tiny2040 microcontroller, again, running the latest version of #circuitPython. Having found a box of old blown Valves (Beautiful objects!) Phil thought he would try to convert them into a useful light, using an RGB led, a button and a sliding potentiometer.

Phil did wire up a classic 4 legged RGB led & got it working, but had some very neat, single “NeoPixels” from Ada Fruit lying around, so soldered some pins onto one & used that, as instead of needing 3 separate pins to control the Red Green & Blue pins, you can do that all through one pin on the NeoPixel. There’s even a handy library to help ease the controls of changing the light colours / intensity.

First, Phil wired the push button into a digital pin (GP7) + Ground, then added a sliding potentiometer (you need 3 connections for this input, a constant 3v, a ground connection, then your “reading” (analogue) connection (A3)). Lastly, phil connected the 3 wires (5v, Gnd + A0) to the NeoPixel. Because you can “chain” NeoPixels, be sure to use the “in” side of the NeoPixel. Phil then drilled a hole into the base of the old Valve, he did this outside (well ventilated) and wore a mask, just in case there are any nasty old chemicals inside the housing or valve itself.

The full code for Phil’s RGB Led can be found here and a wee explanation below:

This project uses a single pushbutton to “cycle through” different states the NeoPixel uses. There is a Dictionary (Dict) that keeps information for LED levels (a “Base” RGB colour + “mix” (potential new levels to be added to the base colour). Each Dict Key is a string that should make the values obvious! The last setting is to make the slider decide what colour the RGB led should be…

Using a few functions Phil wrote for previous projects, you can now pass two tuples (r,g,b) and add them together to return the “mixed” (r,g,b) value – and apply it to the NeoPixel with the simple library method “pixels[0] = (r,g,b)” and “pixels.show()” (to update the NeoPixel).

The slider affects the possible “maximum mix” value by first converting its raw value (130 to 65000+) to 0 & what ever the current maximum value is for that “mix” (stored in the dictionary) this is done for each value (r, g, b). So when the slider is at “0” the maximum possible random number is between 0 & 0 (no new colour added to the base colour!) the higher the slider goes, the more randomness for each Red, Green, Blue “mix” value is possible… so the light starts to flicker within the range of the “base + mix” values…

The Slide setting uses a “wheel” method from Ada Fruit, and we “just” need to map the slide value (again from 130 to 65000+) to 0 & 255. When the slider is moved, it takes its position & passes an RGB value to the Neopixel to cycle from Green to Green over the spectrum. Nice.

NVM : Non Volatile Memory

Not much to show this week from Phil, he’s been getting deep into learning more about OOP in Python, and running into several problems that led him to more exploration, experimentation & fails (so, as we said, not much to show). He also sadly lost his 22 year old cat “Link” this week…

He did however, last week get into “NVM” (Non Volatile Memory) – A very elegant way of writing data to the Pico, so you can save info & recall it when the Pico Starts up again… We had tried using it for the Dinky OSC, but the older versions of CircuitPython didn’t support it, or at least were buggy with the ability to save without hanging the Pico (and forcing “Nuke ReFlashes!”).

Martin had read on the fantastic CircuitPython discord channel that the NVM issues had been addressed in the latest version. And so Phil re-opened his exploration of the use of NVM on a Pico… Phil did a quick search on discord & found :


“you might want to look into foamyguy’s NVM helper in the community bundle https://github.com/FoamyGuy/Foamyguy_CircuitPython_nvm_helper

Phil followed the link, downloaded the library from FoamyGuy and within minutes, had a fully working, easily updateable way of reading & writing info to NVM ! Like a dream you can save a dictionary via NVM_helper & all the byte conversions are sorted in that amazing script… So! Phil is back on track to keep track of the digital Tree , so we can implement the Real Time Clock & apply the effect of time to the tree depending on how often the tree is watered & fed & given sunlight! We will then hopefully see the fully working Tamagochi-esque digital tree…

Week 6: OOP asteroids

With the use of the FFT code to recognise sounds / frequencies, we had an idea that a game could be controlled with specific sounds

With the use of the FFT code to recognise sounds / frequencies, we had an idea that a game could be controlled with specific sounds… Phil started to look at OOP again (Object Orientate Programming) & wanted to create a game of “Asteroids” but instead of pressing a button to “shoot” , making a laser “pew pew” sound would activate the shooting … Ambitious? has it been done before?

Phil loves a bit of OOP, and recently bought the fantastic book by Dusty Phillips and with the previous lessons in creating vectorIO polygons, he started out making a large polygon with randomly spread out “nodes” (thinking about large “initial” asteroids and how they would break down & split into smaller objects, with their own properties of speed, direction (vectors), edges etc).Phil’s 1st attempt at creating Asteroids

There are a few bugs, mostly from edge detection / re-draw – but it’s looking promising!

Week 5: FFT Waterfall

Martin has been following the #AdaFruit example of FFT

Martin has been following the #AdaFruit example of FFT ( fast Fourier transform) to convert the microphone input into a visual representation (spectrum) with great results! The code for this can be downloaded here

Week 3/4 – CircularBar object with vectorIO

A slight “side track” to the flow of the project, but, Phil’s written a document about the “circular bar” graphic idea he had & some of the findings & thoughts as to how to make it better.

A slight “side track” to the flow of the project, but, Phil’s written a document about the “circular bar” graphic idea he had & some of the findings & thoughts as to how to make it better. Click here to download the PDF… This example requires some of the equipment featured above (OLEd screen) – but omits the mic / buttons for simplicity. The zip file of the code.py & libraries is here

Four “CircleBar” objects reacting to a generated angle value in CircuitPython

<EDIT> We’re super chuffed that we got featured in the Circuit Python newsletter </EDIT>

Week 3 : Adding a microphone

We are thinking that we could take the experiment into the realms of “playback / record” by adding a mic to the set up.

We are thinking that we could take the experiment into the realms of “playback / record” by adding a mic to the set up. There are several types of microphones to choose from, Martin started to use a 3 pinned MAX4466 mic, Phil used a 5 pinned Ada Fruit MAX9814 . Martin succinctly states:

“A microphone produces an analogue signal whereas the Pico needs a digital signal to work with. The RP2040 processor has four ‘analogue to digital’ converters, three of which are available on the Pico. An analogue to digital converter, ADC, converts the analogue signal to a digital signal that can be read by the Pico. The Pico ADC’s are 12 bit, returns a value between 0 and 4095. However CircuitPython is written to work across a number of devices and returns a 16 bit value, 0 – 65535”.

With these ranges in mind, Phil wrote the code to convert the mic signal into a range that displays a circle using vectorIO with a variable radius. Previously using circuitPython’s “displayIO shapes“, Phil found that it was difficult to change the size of a circle “on the fly” once a shape object had been created with displayIO. One of the great features of vectorIO is that “radius” is a mutable attribute (the value can be changed “on the fly”), so with a screen of 240 x 240 pixels, Phil placed the circle object in the centre of the screen & converted the mic input range to 0-120 px. After experimentation of what the actual values were for his MAX9814 Mic, Phil discovered that the “minimum” (at rest) was around 24,000 and the peak value was around 36000.

The code below is a very handy “mapping” function in python, we use it all the time in projects to convert a value from one range to the corresponding value in another range!

def mapFromTo(v, oldMin, oldMax, newMin, newMax):
   #v = passed value (should be inside the oldMin/oldMax range!)
   newV = (v-oldMin)/(oldMax-oldMin)*(newMax-newMin)+newMin
   return newV

Download Martin’s Week 3 pdf here

You can also download the zip of all the files needed for this week’s experiment here.

Week 2 – making & adding a speaker!

We love a bit of sound! So, we’ve decided to add a speaker to the Pico set up…

We love a bit of sound! So, we’ve decided to add a speaker to the Pico set up… But with the added fun of trying to make one from scratch!Martin’s DIY Speaker

Martin used some re-cycled motors for the insulated copper wire for the guts of a DIY Speaker & has had success! (all be it quiet, but, this project is about testing, trying, proof of concept etc)…

DIY Speaker!

For the full documentation, & Step By Step Guide on how to make a speaker from a cup & some old motor / electronic parts, download “week 2” pdf sheets, with code & materials lists etc.Phil’s Set up uses a bought speaker & Ada Fruit Amplifier

Week 1 : Pico & OLEd + 2 buttons…

We started with a #raspberryPi #Pico & 240 x 240px OLED.

We started with a #raspberryPi #Pico & 240 x 240px OLED. Having worked with these as a base for the DinkyOSC we thought it would be a good place to start. We’ve added 2 buttons to the set up & control BMPs with adafruit_imageload & displayio . Below is a photo of the initial setup & we’ve included a PDF of the set up etc. here.

Raspberry Pi Pico + OLED screen / electronics buttons on prototyping breadboard.
Raspberry pi Pico + OLEd + Buttons + Breadboard