Full Arduino Mini LoraWAN below 1uA Sleep Mode


great vid and explanation @Charles !


Great video!

So you are going to create a new PCB with the external programmable wakeup chip, right? Will you provide the code to do it and go so low too? Would be really great!


It’s coming and will look like that :wink:


The ULPNode Library is ready, I got some sample code but need to be documented before release because it has lot of features and it’s quite complex.
But I don’t have any time for that, so if someone want to do this job (test and may be adapt sample code already written) and create a well written readme.md on the library github repo, I can open this private repo.
Please be aware that I expect serious work on this, not just take the library, use it for own usage and leave as is.


and don’t forget some corner 3 mm mountingholes… I hate to glue pcb’s in the enclosure :wink:


this could be a solution for a non-hole board. I found no example for 3D printing
… otherwise doubble-sided tape helps :wink:


or buy them


I would like too but I can’t without scarifying board size (and it’s already too big for me), that’s why I reduced groud plane to be able to cut the part on the left when using smaller batteries



Oh nice thing, 100 for 12€ at TME (40€ at DK), next order I’ll buy some for sure

Other size at digikey

And the screws (M3.5 x 6mm)


V1.2 released with Ultra Low Power chip

  • Footprint for Ultra Low Power controller TPL5110
  • 1206 or PTH resistor footprint to easily change delay between wake
  • renamed silk pin to function instead of arduino name
  • Optional Tactile Switch to wake from TPL5110
  • Octopart BOM file

Full repo with building files

ordering V1.2 PCBs is here only with classic I2C connector

Not tested, use at your own risks, but should do the job


Looks good Charles. Will tell my fellow TTN-ers of the TTN Enschede group that there is a new board out there (the workshop where we used your PCB’s was a great succes).


Wanted to check my multimeter limit zone of previous video and add some precision, time to put uCurrent gold to 1mV/nA and here we go with SI7021

Board in sleep mode is 765nA, yes yes this is nA, these old devices are really amazing !!!



I have just received TPL5110 Adafruit board. I can confirm that this is the best way to sleep any sensor. The consumption is so low.


While the TPL5110 is running (but the remainder of the project is de-powered) the current draw is about 20uA ??

must be an error then on their site.


Yeah, the data from Adafruit is non-sense. I can go down to 10uA using several sensors, flash and atmega328p no problem at all.

TPL5110 draws more like 35nA while the rest of the project is asleep.

This is actually difficult to measure such a small current without a lab equipment. uCurrent Gold is noisy on nA and good DMM resolution is not that good. Keithley Picoammeter has to be used.


Do you mean me asking Charles - how did you get 0.78nA?
This is the board without TPL5110, right?

I am getting 2.9uA on your board V1.1 with BME280.

BME280 (0.2uA)
RFM95W (1uA)
Arduino Pro mini - the rest (1.7uA)

Cannot get below it.


the board on the picture is as simple has
Arduino Mini 8MHz 3.3V (no regulator or power led)
SI7021 direct I2C wiring (no regulator)
RFM95 direct SPI wiring with DIO0/DIO1/DIO2 connected see schematic on github above

Removed BOD from fuse (can be done by software) and no Watchdog use, that’s it but may be my measurement are not “so good”, but look like the same with my multimeter (1uA) and UCurrent (0.778uA) so I think I can trust the results


This is exactly my setup, however, there is still higher consumption.
I have uCurrent Gold and it shows me very similar readings to with my DMM (121GW), which is 2.9uA


would you give us your sketch so I can try on my side?

(Jenerts A) #220

I have implemented TPL5111 in my design. sadly dont have meter that can messure below 1uA.
Added some DIP swithes so you can choose what time interval you need.
Here is some lates pcb 01
Still wating for it to arrive, but similar design is in field up un running for almost 2 months.

(Gry Kyo) #221

Screenshot_2018-09-16-17-18-29 Ch21_Emvornmental

So just using one of Charles’s PCBs, a bog-stock Chinese arduino clone with only the linear reg and power LED removed this thing is pretty amazing.
I fitted a LiFeP04 cell into this node as the cell shipped to me in week 2 of April. It read 3.3v then and having woken, polled a Bosch sensor and transmitted to TTN every fifteen minutes since it still shows 3.3v! That would be 96 cycles per day or about 10k wake and transmit cycles.

I am thinking that one of the current breed of low power devices with SI7021 and TPL5110 type manager chips has power to see it well into obsolescence, no?

Well done and many thanks @Charles!