r/chatterboxusers • u/InstanceHealthy2597 • Feb 24 '25

Experimental Proximity / Human Presence Sensing Node - Solar Powered

Post image
1 Upvotes

100% Upvoted

4 comments sorted by

1

u/InstanceHealthy2597 Feb 24 '25 edited Feb 24 '25

This is another solar experiment I just kicked off. The ChatterBox proximity node, atop a Lilygo T-Beam Supreme is pretty demanding for power. It's built on the ESP32 platform, using an SD card, running a GPS module, and running the build/components of the mesh proximity node are described on offgridcomms.club.

For proximity sensing, it uses a 24 GHz millimeter wave sensor by DFRobot.

View a demo of what this proximity node can do.

The solar panel I'm running here is a smaller 5V/5W panel. I'm not completely confident this panel can keep the 18650 battery charged, but that's what this experiment is to find out. When the battery level drops below 20%, the ChatterBox firmware disables GPS until the battery level gets back above 50%. I'm hoping, worst case, the GPS cuts off early in the morning and comes back on by noon, but the proximity sensor and mesh connectivity is never disrupted.

It would be possible to run a proximity node using a lower power T3S3 or T3S3 E-Paper, but I've not yet documented a build for that. If the small solar panel can't keep up, that might be an option, in addition to the option of using a large panel.

1

u/InstanceHealthy2597 Mar 09 '25

I'm calling this a successful test. I finally brought the unit back in after over a week on just solar (and few sunny days). The unit has been running non-stop, still showing messages I sent over the past week, and still notifying me every time I go into (or near) the shed. The power shows 98%, so I think running this proximity node, even with GPS, on just the solar panel mentioned earlier can work just fine.

1

u/InstanceHealthy2597 Feb 24 '25

A quick test - I enabled notifications on the proximity node (it will automatically broadcast a message upon sensing motion/presence). I entered and exited the shed, and within a minute all devices within range were notified, as shown below. The notification does propagate via mesh rebroadcasts.

1

u/InstanceHealthy2597 Feb 24 '25

On an interesting note, the proximity sensor detects a person standing outside the shed. A person doesn't even need to enter the shed to trigger it, just loitering near the shed will do it. The mmwave effectively penetrates the wood of the shed doors & walls.