Hi
I am running the Pico RGB Keypad with Micropython and setting the brightness to zero.
In this state the power draw is around 50ma. Is there are way to reduce the power further ?
#code sets leds off!
for find in range (0, NUM_PADS):
keypad.illuminate(find, 0, 0, 0)
Neopixels will still draw current when the LED is off, because the control chip is still running. For WS2812s this can apparently be up to 1mA per LED, I assume it is fairly similar for the APA102s in the keypad. There is data floating around on the internet suggesting that a bare Pico in MicroPython will always have ~26 mA draw, unless you put it into something like deep sleep to actually partially shut the chip down.
At the end of the day, I don’t think the Pico (or RP2040/RP2350) are considered particularly battery friendly compared to other chips.
@Shoe
Many thanks. Yes was thinking it was probably that, Was hoping there might be a way to switch the power off (some of the Adafruit boards can power off the neopixel) but looking at the schematic there doesn’t appear to be anything.
Will have yo go back to the drawing board for this one!
Many thanks!
You can see some figures regarding power in various sleep states here: GitHub - bablokb/pico-sleepcurrent: Test programs to measure current consumption during sleep for the Pico. Now this is with CircuitPython, but that is not relevant for current consumption.
Also note that 26mA is for 5V. If you go down to battery voltage levels, you will have more. The Pico will always draw about the same amount of energy, so with lower voltages it is higher current. I measured for 2.2V from two AA batteries an idle current of 82mA. As you can see, you also loose something due to the internal regulator of the Pico.
The RP2350 has better low power states, but this is not yet implemented in the SDK. Once it is there, I expect it to trickle down to MicroPython and CircuitPython.
Just for comparison: RP2040 deep-sleep is something like 6mA (time-alarm) or 1mA (pin-alarm). The ESP32-S3 Feather from Adafruit has 18µA in deep-sleep. So as you noted, the RP2040 is not the best choice for battery-based projects. Unless you switch power, as Pimoroni does with their InkyFrames (or Badger2040W).
Thanks for the info. That’s a lot of work you did on testing the Pico power draw, very useful !
Yes it clear the Pico is not a good choice for low power battery projects.
This is not a battery project but on 24/7 and I have become a bit of a geek about reducing my overall leach current, but 50ma@5V, 2.2kw pa or 50p, I need to get a grip ;)