Topics created by kisse66

The atmega328 implementation of MySensors sleep wakes up every 8 seconds and result in many years of battery life, so waking up on the nrf5 shouldn’t be much of a problem I think.

I tried all the options and maybe got a bit better battery life. However I have now found out, that the actual problem is not likely radio connection after all, but I2C related problem. Started getting more of random drops and after adding some more debug stuff I finally found, that it sometimes get stuck in HTU21 driver, that had a forever loop if there was no proper response. The driver code has later been modified (Adafruit) to avoid this loop. I had my own async version of it, which had the same bug (same code, but split into start() and read() to avoid the delay saving run time). So likely this random dead battery issue was forever loop draining the battery. Have no idea why it sometimes rebooted by itself, recently it has just died and after reset (battery off and back on) the battery is more or less empty.

@nca78 about 27uA (Rigol DM3085) @3.2V. It only drops 1-2uA if I disconnect the sensors (all wires towards HTU21,BMP085,VEML6075, BH1750) which is about what the datasheet for those say under shutdown. So most is taken by NRF52. There can be other peripherals that could be turned off still before sleep maybe. Now I only handle the I2C errata and then shut it off before sleep (wire.end), the rest is in mysensors code for sleep. Sleep current does not change if I don't enable the DCDC. Perhaps the active current does a bit but can't measure it accurately (too fast). Just estimated that using AA-batteries it should last over 2 years. It only wakes up every 20min and runs about 400ms to send 7 values. But still I'd like to get better. This is my rain gauge / multisensor under upgrade. It was earlier powered by mega328+NRF24. Worked fine about a year, but then something happened and it started taking 2mA while sleeping. Didn't see any visible reason why.

One more update: have not fully verified, but it seems like this was RF interference issue (maybe a transmitted ACK??). I added a 100n ceramic cap to power in line (at the GPIO connector) and 10nF caps from UART TX and RX to ground (small SMD caps at the connector). I also moved the antenna a bit higher by soldering coaxial cable to RFM and then peeling off the outer shield of the coax for the ~80mm. Problem gone! I'll add a ground plane to the antenna by putting aluminium tape to the top cover (missing here) and connecting the coax shield to it. Makes a better antenna and better shielding towards RPi. Have not re-checked range yet, but checked the UART signals with scope and the 10nF looks good as noise filter.

You're very welcome @kisse66 I hope others find this useful too!