A Multi-Channel Wireless Voltmeter
This voltage measurement setup lets you monitor up to four sources at once.
Measuring voltage output is, one might argue, the most basic of electronics diagnostic techniques (after turning it off and on again). This simple reading can tell you a lot about how a circuit is functioning, but what if you need to keep track of multiple voltage readings at the same time? And what if the voltage sources aren’t necessarily in the same room? Such a situation would normally be quite the conundrum, however, this four-channel wireless voltmeter is perfect for such a job.
The setup consists of a central receiver unit, running on an Ardiuno Nano, with a 128x32 OLED for user output. It communicates with up to four transmitters via an nRF24L01+ wireless transceiver module. This gives it a range, according to the project’s GitHub page, from “a few meters to tens of meters depending on how well the radio module is isolated from the controller, and the RF power setting.” Its little display shows voltages, as well as battery and communication warnings, on a summary screen. One can also “zoom in” to a single channel view for a bit more info.
Transmitters are driven by an ATtiny402 microcontroller with nRF24L01+ radios for communication, and can measure between 0-20V. These are optimized for minimal power consumption, and can operate on weeks or even months depending on usage and implementation. The system is demonstrated in the video below, and as seen toward the end of the GitHub intro, one of the little transmitters was even stuffed into an automotive OBD-II plug!
