Battery powered sensor drawing too much current

[Jan Greis]

I'm trying to build a battery powered temperature and humidity sensor. I used the wiring from https://forum.mysensors.org/topic/486/my-2aa-battery-sensor and started
with the sketch from https://www.mysensors.org/build/humidity (battery monitoring will be added later). Exact components are:

• https://www.aliexpress.com/item/10pcs-lot-Pro-Mini-328-Mini-3-3V-8M-ATMEGA328-3-3V-8MHz-for-arduino/1967122432.html?spm=a2g0s.9042311.0.0.M4C5Ug
• https://www.aliexpress.com/item/10PCS-NEW-NRF24L01-2-4GHz-Antenna-Wireless-Transceiver-Module/32327366606.html?spm=a2g0s.9042311.0.0.dT2xho
• https://www.aliexpress.com/item/New-Electric-Unit-1-PC-NEW-DC-0-8-3-3V-to-DC-3-3V-StepUP/32724361266.html?spm=a2g0s.9042311.0.0.dT2xho
• https://www.aliexpress.com/item/DHT22-AM2302-Humidity-temperature-and-humidity-sensor-probe-digital-output-Free-shipping-to-Malaysia/1086124515.html?spm=a2g0s.9042311.0.0.M4C5Ug

The sensor works fine and reports the measurements to the gateway, but is drawing too much power to feasibly run on battery, around 8mA consistently, i.e. whether in sleep or not. The power LED has been removed. There may have been some short-circuits from sloppy soldering initially, but I'm fairly confident they have all been resolved now. At this point I don't know what else I can do to try to diagnose this, so I would be grateful for any ideas.

[Yveaux]

@jan-greis Hi there and welcome to the forum!
The best way to reduce the power consumption of your sensor setup is to get rid of the stepup converter and select a different humidity sensor, like the BME280.
A setup of ProMini 3.3V, nRF24 and BME280 can be directly powered from 2xAA battery (without stepup) and should be able to run for a few years on a set of batteries.
To monitor the battery level you could use my Vcc library: https://github.com/Yveaux/Arduino_Vcc

[Jan Greis]

@Yveaux Thanks for the suggestions, will definitely look into this. I suspect though that something is actually going wrong with my setup, since with this power draw, I couldn't possibly reach the longevity that @m26872 got out of their sensors using the same components. Especially the fact that my draw doesn't seem to reduce at all while sleeping seems very strange to me and to me suggests that something other than the hardware specs are to blame.

[rozpruwacz]

I would suggest to connect things one at a time and measure power consumption in between. First start with just a pro mini board powered straight from the battery and nrf module connected. Make a sketch that just go to sleep and upload it. During the sleep You should get couple of uA current consumption.

[gohan]

Remember to remove the voltage regulator too from the pro mini. If you want to go to a smaller size, you can use a single LiFePO4 battery

[m26872]

@jan-greis With all respect to the criticism I don't think original part configuration is that bad. I don't build any new of them but I still use a few as frequent reporting nodes. If you already own the parts and you need a frequent awake node -why not?
If I recall the sleep mode should be 90-100uA with this setup. Low power nodes have <10uA.
Troubleshooting method should be the usual. Exchange components, test them one by one, etc. Start with testing the step-up quiscent current, then run test Arduino only in sleep (low power lib not Mysensors-lib), then add DHT, then nRF.

[Nca78]

Hello,

8mA looks like your atmega running constantly and not going to sleep.
Can you provide a log for your sensor ?