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MariusGundersen

Member since May 2022 • Last active Nov 2022
  • 2 conversations
  • 5 comments

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  • Avatar for MariusGundersen

    I tried with this program:

    setDeepSleep(true);
    B9.reset();
    //B9.mode("input");
    

    It draws a steady 312uA. When I change the commented line so that B9 is input it draws 89mA, so it seems like the wifi chip is enabled then. Probably there is some charge left that isn't drained, leaving it on (my guess here). This is with the e-ink display disconnected.

    I tried a few different things but couldn't get it below 300uA. Unfortunately I managed to short my cheap multimeter, so now it's not saying anything at all...

  • Avatar for MariusGundersen

    I have a Pico connected to a wifi module through a shim and an e-ink display, and it's all powered by 3 AA batteries. This setup wakes up every hour to fetch data and refresh the e-ink display. The code is here. Unfortunately the batteries only last about two weeks, which is a lot shorter than I expected. I've measured the power draw using a cheap multimeter, and it draws about 90mA when the wifi is active, 20mA when refreshing the e-ink display, and 0.9mA when idle. I've set it to deep sleep, I disable the wifi and power down the e-ink display, but that is still too much power consumed, IMO.

    I'm wondering if the serial connection could possibly consume some power, through pull up/down resistors? Or maybe it's the voltage regulator? Any other tips to limit power consumption?

  • in Projects
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    This spring I got the idea to use a framed edp (e-ink paper-ish display) with a wifi connection to show the hourly electricity price and consumption. The electricity prices here in Europe have gone up quite a bit, so it's nice to pay attention to when during the day they are the lowest.

    So it's using a display from waveshare that can show red, white and black. I've written some code to dither other colors down to those three. There was no library for espruino, but there was some python code that I could easily convert to javascript. The hardest part about getting it to work was finding that reset needed to be toggled for only a few milliseconds, not several seconds. Weird.

    The next step was connecting to the wifi. I've used the esp8266 wifi module soldered to an espruino pico using the shim. Getting it to connect was really easy, it worked on the first attempt. But then getting it to connect again an hour later didn't work. After a lot of work I ended up rewriting the wifi module so that it doesn't connect to wifi as part of the setup call. I also changed some parts to use promises.

    The final problem was getting the deep sleep to work. I want this to run on batteries for as long as possible so it should deep sleep between refreshes (every hour). It should also disable the wifi and the e-paper controller.

    That's a short summary of where I am now. The problem I have is that the battery is drained very quickly, IMO. Three AA batteries in series are drained in about 12 days. It fetches the image to show every hour, so about 300 times before it dies.

    The batteries are not completely drained, the combined voltage is way above 3.3v, so I suspect there is too much peak current being drawn. Any tips on how to improve this?

  • in Porting to new Devices
    Avatar for MariusGundersen

    Given the new pi Pico W and the wait for the espruino wifi, I'm getting interested in this port :)

    https://t.co/2leMu87zwC

  • in Porting to new Devices
    Avatar for MariusGundersen

    Given the new pi Pico W and the wait for the espruino wifi, I'm getting interested in this port :)

    https://t.co/2leMu87zwC

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