Power – Arduino Low Power Sensors
December 29, 2015
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Since we last visited the sensor network in mid-December, we have tested the range of the previously built sensors, by placing them into some cheap plastic food containers.
These were not meant to be low power items, more just to validate software and connectivity through the nrf24l01+ wifi units, back to the base Raspberry Pi (RPi).
This worked well as a validation for each subject area. The next step was to try to determine if the Nrf24l01+ we sufficient for the communications job. One modification was that we had to move the receiver to near a window, to extend the range to 60-70 feet, which was successful.
That was the good news, the bad (but predicted) news was that a 9 volt battery did not last long in either the Uno based unit (15 hours) nor the Pro Mini unit (22 hours).
The next step was to either rewrite the code in these units to automatically power down and back up when we wanted to transmit, or to find ways to reduce the power used by the regulators and on-board LEDs. I have chosen to go a slightly different way by re-embracing of the mysensors.org environment, then adjust what they deliver to the hardware I have in hand.
My first step has been to re-purpose the arduino pro mini [PM5] (16mhz 5v) to be the serial gateway for this. I was able to download and setup the “serial gateway” from their web site, and am proceeding to build a new sensor device to their specifications. The next step in this environment is to pick a controller. The group has purchased Raspberry Pi units, so that will be the device to deploy to.