After testing various small Solar Panels for the Boron LTE in this post, I decided to figure out how to operate a Low Powered Boron while we are awaiting Sleep Modes for Gen3. (Special Thanks to @Rwb for your help!)
The answer is the EN (Enable Pin), which works for all Gen3 Mesh Devices.
I’m now running 2 more field Trials:
Boron LTE, 0.5-watt Solar Panel, 2,000 mAH Li-Po, external Timer for EN Pin to Shutdown Boron between scheduled Publishes @ 5 minutes, TMP36 to monitor temperatures inside enclosure (to disable Li-Po charging when temps are too cold/hot). RC-25 Firmware, mesh NOT enabled during initial setup w/ IPhone.
Boron LTE, 3xAA, external Timer for EN Pin to Shutdown Boron between scheduled Publishes, for an Indoor Project since Solar isn’t an option. RC-26 Firmware, mesh WAS enabled during initial setup w/ IPhone.
Boron LTE Power Consumption:
I wrote code for a Photon that uses a 16-Bit ADS1115 and the µCurrent GOLD to measure the Power consumption of the Boron when powered via it’s Li-Po Connector. It averages 100+ differential 16-bit readings each second to calculate average current, totals the power over time, and prints a results line to serial every second.
A sample result for a 4.10V powered Boron LTE on the Li-Po connector includes: Startup, Cloud Connection, Publish, plus 1 sec before Shutdown is :
Power: 1.053 (mWh) 0.0011 (watt-hour) 0.925 (amp-seconds) Total running time: 14.07 (seconds)- this will change depending on location / cellular reception.
The Boron LTE’s average current when the EN pin is pulled LOW is
76 µA (Argon & Xenon are half that).
It’s easy to see that a tiny 0.5-watt Solar Panel & Li-Po can meet the power requirements for a Boron LTE that’s shutdown via an external Timer, on a reasonable schedule. I don’t expect any surprises for Trial #1 listed above. The enclosure is roughly 4"x2".
Trial #2’s Boron is operating on 3xAA batteries (Energizer L91) via the Li-Po connector and the same external timer to Shutdown via EN Pin between Publishes. The L91’s provide 4.5 watt-hours @ 100 mA load. Quick math says the 3xAA Boron should be capable of 4,000+ publishes. In my testing, Successive Cloud Connections have not taken any longer on the Boron LTE than it does after being without power for 12 hours.
Trial #2 is publishing every minute to speed up the 3xAA test. It’s Awake time is averaging 12 seconds before it shut’s itself down after the publish. It publishes the 3xAA battery voltage, the processor time for each wake cycle, and the total number of publishes since the trial began. The # of publishes are read/stored to EEPROM each cycle. I should know in a few days how close the 4,000 publish estimate is to reality. I’m using a 6xAA battery enclosure for the 3xAA batteries and Boron.
This is the external timer I’m using to Ground the EN Pin for Gen3 Shutdown:
It’s a great option for Gen3 projects that can operate on a schedule.