Customer:
I purchased an Inkplate 6 and ran a program that periodically updates the screen, sleeping for 15 minutes between updates. It worked flawlessly for more than 3 months but after some Wi-Fi troubleshooting following a router upgrade (which included re-flashing the Inkplate several times), it randomly gets stuck, apparently waking up immediately after sleep mode is initiated and just updating the screen repeatedly in a loop. I have not been able to reproduce the behavior while plugged into my PC to monitor the serial output.
I’ve come across reports of some early Inkplate boards having trouble with sleep functionality while running off battery power. I’m not sure why the problem would only appear after a couple months of working correctly.
Originally submitted via email support on 24 April 2023. Migrated to the forum for community visibility.
Soldered Support:
This seems to be a power issue. Can you try with another battery or another cable, and also try a better power supply? It could also be caused by a bad fuse.
Do you know if the Inkplate wakes up or if it keeps resetting?
Customer:
As I stated before, I have not been able to reproduce the behavior with the serial monitor active (powered through a USB cable) so I can’t say for certain what’s happening. As far as I can tell though, the entire program is completing successfully since the screen is refreshing and that’s the last thing that happens before sleep mode is engaged. I don’t think I have another compatible battery on hand but I’ll look.
Soldered Support:
If the program is completing successfully, then it is most likely a power issue. Try another battery.
Customer:
I was tracking down another battery and doing additional code troubleshooting. It’s a slow process since it can take several hours for the issue to present itself after powering on the Inkplate. All the troubleshooting has shown that the code is executing correctly and a different battery did not help. Every time I try to use it, eventually it will start failing to sleep and just execute the program repeatedly until the battery is drained or I turn it off.
I have found some old troubleshooting threads on Github where people were told that there was an incorrect capacitor on some early production boards that resulted in similar behavior and were advised to solder on another capacitor in parallel (see Unexpected behavior under battery only · Issue #56 · SolderedElectronics/Inkplate-Arduino-library · GitHub).
I don’t know enough to determine if the problem I’m experiencing is related. It also seems unlikely that the board I purchased is that old, but it’s possible.
How should I proceed?
Soldered Support:
Could you please send us a photo of the back of your Inkplate board? We have a few ideas on what the issue could be and a photo would greatly help us solve your issue.
Customer:
I have attached a picture of the back of the board.
Attachment omitted in migration: DSC_7323.jpg
Soldered Support:
After consulting with a colleague, we suggest you try adding a 4.7k Ohm pull-up resistor as shown in the sketch attached below.
Let us know if this works. If not, we will try to figure out another solution.
Attachment omitted in migration: image.png
Customer:
I got the resistor soldered on as indicated and I have not experienced the sleep issue for 24 hours now when previously the issue would present itself within a couple hours, so it seems to be fixed.
Could you provide some details about what the core problem was and why you think this may have popped up without warning after several months of running flawlessly?
Attachment omitted in migration: image.png
Soldered Support:
We changed some code which works with the power management IC, which could result in a greater current consumption during Inkplate’s start-up. This resulted in noise on the RESET line, which triggered the voltage supervisor chip, which caused a reset of the ESP. Other various factors on the board could contribute to this as well. We have fixed this issue in the newer versions of the board.