Node low power consumption
The BANO node runtime is designed to limit the node power consumption without exposing hardware related details to the developer. I got the following measures using hand made instruments. I checked everything carefully and I am quite condifent about the measures, but errors are still possible.
During the development process, power was measured to be to 300 uA at approximately 3.1 V in passive mode, with wake on interrupt enabled. In the door monitoring application, this is the default state. In practice, it allows a node to be powered using a 1000 mAh CR2477 coin cell battery for weeks.
I was also interested in the total power profile of sending one message over RF. At first, I measured it using a regulated power supply (ie. constant voltage set to 3.1V), so to have a feeling of the power:
The current raises to around 25 mA for 5 ms. I knew it would be a problem for the coin cell. It actually was, and the battery voltage dropped too much to power the node electronics. I had to put a 330 uF in parallel to handle the peak. Here is the resulting profile, this time powered by a coin cell battery:
The voltage drops to 2.8 V during message transmission, which is fine as regard with the on board electronics. However, the node runtime should be careful not to send messages if the capacitor is not fully loaded. This is not an issue in the door monitoring application, but will have to be implemented for future applications.