One of our Frequently Asked Questions is “What can micro-batteries, with capacities below 1 mAh, actually power?”. The answer comes from the careful calculations of the energy budget, the use of now commercially-available ultra-low power components and the combination of solid state batteries with efficient energy harvesters.
In a previous video, I have demonstrated how 180 µAh solid state batteries could operate an industrial-type temperature sensor beacons in hostile environments. In this blog, I am explaining how this was made.
The photographs below give an impression of how small the device is. It is powered by a combination of solar cells from the UK company Lightricity which are particularly efficient indoors, with one or two Stereax P180 (depending on the use case), 180 µAh solid state batteries. These batteries are particularly efficient when operated at high temperatures. In fact they can operate up to 150°C.
The most power hungry part of the device is the transmission at regular interval of the data measured by the temperature sensor. We used a Bluetooth® Low Energy module which has the following duty cycle. Here are the events:
- Power on
- Software runs
- Trigger I2C & ADC
- I2C acquire + write
- Radio TX