The Pico W I recently bought to try out the “Pico RGB Keypad Base” does not work with the “LiPo SHIM for Pico” and a supposedly compatible battery pack “LiPo Battery Pack - 2000mAh” also from Pimoroni. I have rechecked the soldering multiple times and it matches the guide on the product page. I also had someone else double check for me in case I missed something.
When the battery is not connected, the micropython demo (pimoroni-pico/micropython/examples/pico_rgb_keypad/demo.py at main · pimoroni/pimoroni-pico · GitHub) works without problems. However, I can hear a high pitched whine from the Pico (or the Shim?).
When only the battery is connected (USB cable is disconnected), the demo doesn’t seem to work. The keypad doesn’t light up anymore. Weirdly enough it seems to register me pressing the buttons. When I connect the USB cable after having pressed some of them (with the battery connected the entire time), the RGB LEDs light up with the button’s I pressed in green, and all other LEDs in white for a second before everything goes dark again. Reconnecting the USB cable afterwards will not cause it to light up again.
Keeping the USB cable connected does not fix the issue, only when the battery is disconnected does the Pico work correctly. The battery should be fully charged, the white LED (power) is lit and the red LED (charging) has stopped glowing. The battery pack is at 4.15V.
A simple blinking script (Programming Raspberry Pi Pico with VS Code and MicroPython | Random Nerd Tutorials) works with only the USB cable connected, with only the battery connected and when both are connected.
Does anyone know how I can make the Pico work with the LiPo shim and the battery pack?
The RGB Keypad Base requires (+5V) VBUS input to supply power to the LED’s. It won’t work with only a VSYS input. The LIPO Shim only supplies VSYS. This combo isn’t going to work. The Pico Lipo Shim can power the Pico, just not the RGB Keypad Base.
pico_lipo.sch (shopify.com)
pico-matrix-keypad.sch (shopify.com)
Raspberry Pi Pico W GPIO Pinout
ah, that certainly explains it. Do you have a suggestion how I could salvage this? I would like to use the battery if possible
If you want to power the Keypad base via battery you’ll need a Power Boost or similar device.
PowerBoost 1000 Charger - Rechargeable 5V Lipo USB Boost @ 1A - 1000C (pimoroni.com)
great! thank you very much
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You might even get away without the Power Boost, but the lights will be dimmer. But my experience is that the APA102 need dimming anyway.
In any case: if you feed power directly to the VBUS-pin, you have to make sure not to connect the USB-cable to something else at the same time. Feeding through the USB-connector is fine, but in this case the LiPo-Shim does not make sense.
I have an RGB Keypad on my desk setup as a USB HID Keyboard, connected to my Windows PC. I’m setting my brightness to slightly less than 50%. I’m using (42, 0, 0) etc. It’s what works for me, not overpowering / distracting in dark conditions, and still discernable in bright light.
If I use the Power Boost or the LiPo Amigo Pro (LiPo Amigo (LiPo/LiIon Battery Charger) | The Pi Hut) and connect the 5V to VBUS can I still use the USB of the Pico for programming? Or do I need to keep the charger disconnected while I program it?
I’m also assuming that if I power the Pico through VBUS, I shouldn’t connect anything to VSYS, correct? I would like to avoid damaging the Pico.
Be careful not to mix up different options:
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normally, it is no problem to connect USB (including power) to the Pico and to connect power to VSYS, as long as there is protection against back charge. Both the LiPo Shim and the LiPo Amigo have this protection. The LiPo-shim also takes power from USB to charge the LiPo, but not via VSYS so this is no problem.
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if I understood correctly, you already soldered the LiPo-shim to the Pico and now you have problems with the LEDs of the keypad, which happen to use power provided by USB (i.e. via VBUS). You could shorten VSYS and VBUS, thus providing at least the LiPo-voltage (attached to the LiPo-shim) to the LEDs which might just work. But in this case you should not power the Pico via USB.
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Third option: remove the LiPo-Shim (or at least don’t attach a LiPo) and use a boost-converter with attached LiPo to convert the LiPo-voltage to 5V and feed this into USB or VBUS. Again: if you feed it into VBUS, don’t connect USB or you will risk back-powering - either from USB to the boost converter or from the boost-converter to USB.
The third option is my current plan. So I should only connect 5V to VBUS once I have finished programming the pico.
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I have the same issue on my Interstate 75 setup. It has its own dedicated power supply that will back feed +5V through the USB Jack. What I did was modify a USB Cable. I cut the +5V wire. Only the Data+, Data- and Ground are wired through to both ends. My i75 has two 64x 32 LED panels attached. It’s iffy at best trying to power it via a standard USB A Jack.
It worked so well I also use it with a Plasma Stick setup that has its own dedicated Power Supply wired up to the screw terminals. =)
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