discussion / Biologging  / 27 February 2019

extending battery life with solar panels

Is anyone out there up for a development challenge involving "smart" GPS and accelerometer collars with extended lifetimes (arorund a year), possibly involving solar panel  recharging ?

Hi Peter,

You could use the open source Arribada GPS and accelerometer reference design as the base tag and add solar to the enclosure to trickle charge a Li-ion battery. The same reference design is currently having a LoRa radio added via the Open Collar initiative, so sharing the design to include solar would be of benefit there too.

It was primarily designed for sea turtles - https://twitter.com/arcpatricio/status/1041644023407149056

Tag size here - https://twitter.com/Al2kA/status/996125000531922945

Kind regards,



Hi Peter,

That's great, do keep in touch. FYI - the Rev 3 Arribada Horizon reference design will be inherited in the next OpenCollar tag and will benefit from the nRF52840 (Rev 2 was the STM32) meaning a deep sleep current of ~20μA, which means you'll in a good position to achieve your power requirements. First boards will be built and tested in a few weeks time.

Thermopiles - it's all about the vaccum sealed optics. Heinmann Sensors are in the process of testing the latest optics on horses / cattle at various distances to confirm performance. I'm writing an update so will share it once done with a little more insight.

All the best,


Hi Harold,

I had a brief crack at using a 'shaker torch' (i.e. magnet and coil) and it seems plausible at least. I even wrote to Seiko about whether they'd give me a kinetic mechanism from one of their watches, but, whilst they were postive at first, I couldn't coax them out of one...Watching animals like dingoes trot along with collars on, swaying a little back and forth, really makes think it could work...Thoughts?