Raspberry Pi Pico

Raspberry Pi’s answer to the Arduino Nano is here!

Website: https://www.raspberrypi.org/products/raspberry-pi-pico/

Datasheet: https://datasheets.raspberrypi.org/pico/pico_datasheet.pdf

Best of all, it’s only $4!

It’s not suuuuper synth-friendly out of the box since I think it only outputs at 3.3V (need confirmation on that), but it looks like it has a lot of potential, and it’s significantly more powerful than the Nano, maybe even powerful enough for some proper DSP.

To me, this looks like a perfect target to try to build some Vult applications/filters/effects on, so I’m looking forward to see people building a Eurorack framework around this.

Thoughts, ideas?

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I ordered 3 (the max) right after getting the email announcing it :slight_smile:
Added the audio pack, decker and some proto boards.

16 PWM out with, a priori, up to 16 bits resolution at a decent rate (a fast scan thru the datasheet seems to indicate rate decreases as resolution increases…).
Only 3 ADCs, 12 bits, but with a fast sample rate (up to 500 Ksamples/s)

3.3V isn’t that bad, to get it to play really nice with the rest of your modular you wan’t opamps to buffer the signals anyway, 5V or 3.3V.
Or at least transistors for gates/triggers.
(A lot of arduino projects don’t have opamps… and people always run into problems when connecting them to some modules… for what I can see in forums like electro-music or muffwiggler)

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The microcontroller has 4 ADC pins but the fourth doesn’t connect to one of the board pins. By comparison a Nano has 8 ADC input pins. So that’s a significant limitation for synth use.

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I have literally ordered one of these this morning and it should arrive tomorrow, along with the 4x4 RGB silicone touch pad shield. I saw the ADC limitations, but I have a feeling that using it as a state machine would make for a very nice, and highly flexable, multi-channel trigger sequencer for a drum machine module coded in MicroPython.

I have high hopes that incorporating a few extra buttons and some output jacks (and probably a few opamps to bring the 3v3 IO up to a more acceptable trigger voltage) will produce something I can use with my drum PCB’s and CTorps EG’s.

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Other companies including Arduino are also making RP2040 boards:

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Ooof, the price of that Sparkfun board though… I could buy three or four of the Pi Foundations implementation for that… Having it in the feather format will be nice for the folk who use it though, but again everything Adafruit has a premium price tag.

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The fourth ADC is used to monitor the voltage…

The Nano has only 10 bits resolution, and what sampling rate ?
And in fact, the Nano has only ONE ADC and an 8channel multiplexer.
Which reduces that more the sampling rate.

The Pico has 3 (available) ADCs, with 12 bits resolution and a sampling rate up to 500 Ks/s.
If you need more, add one (or three…) 8 channel multiplexer chip, it will still sample much faster than the Nano, and it doesn’t eat up the digital IO pins (well, maybe 3 pins to set the channel if the multiplexer isn’t I2C controllable).

Also the PWM output are much nicer than on the Nano.

The Pico SDK looks nice to me, much closer to the hardware, thus faster than the arduino SDK.
And it won’t take long for somebody to port the arduino SDK to the Pico.

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For audio signal processing, sure. But I don’t see most synth CV inputs as needing a higher sampling rate than the Nano, and 10 bits isn’t bad for most purposes. Though indeed marginal at best for accurate V/Oct over more than a 5 V range, if that’s what you need.

Of course you can get more ADC inputs with external hardware. But the appeal of these microcontroller modules is how much you can do with what’s there.

They both have their strengths.

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Being “better” doesn’t mean you need it :slight_smile:
Or else the nano would be dead for a long time…

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I’m def interested in this. The micropython option is also nice.

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Looks very interesting! I ordered a couple, but it was a pre-order in The Netherlands, so I’ll have to wait until February 2nd.

I think I will take a look at micropython too. I never programmed in Python before, but it looks nicer than c/cpp (which is not really my thing).

I already ordered two of them. If find the programmable IO (PIO) pins most interesting. As far as I understand you can programm multiple state machines which control output pins. That would be a great addition to my Arduino Nano based DCO to control multiple oscillators with one Pico.

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On my list since announced. Love the 16bit Res. My own rules prevent ordering before I have a project but I have a few EWI and string projects that may benefit. Less enthused by the python side as it took me an age to get back into C++ and C# already. Shout out if you have any ideas.

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Grrrr… Pimoroni were supposed to ship mine yesterday (with next day shipping) and it still hasn’t left the warehouse… Oh well, I have other things to be doing whilst I wait.

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It has arrived!!

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After assembling the keypad base I can officially say that in order to get it behind a panel is going to take some finesse. The pico itself sits higher than keypad ‘sandwich’ board holding the squishy parts down which would mean that simply replacing the sandwich with a PCB front panel would result in a crushed pico. It’ll need additional boards for spacing and much longer screws and bolts to hold it in place etc.

It does however make for a very handsome prototyping tool, and if it’s libraries address the switches and led’s in a similar way to a NeoPixel Trellis then it’s still going to be extremely useful as a tool on my workbench as for ‘production’ models I would just swap in the easier to mount component.

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Cool. What sound (dac) hardware is available / compatible with the Pico?

There is a breakout board providing a line out and headphone driver currently, but you could use any DAC chip you like on the digital IO pins.

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Link please for the touch pad?

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As it’s a UK based store, your mileage and delivery speed may vary. They are good though.

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