Dead Solar Panel

A couple of days ago I discovered that the solar panel was not working. The day before that, the solar charging data had indicated that it was only charging the battery for a few hours near noon, and usually it charges the battery whenever the sun is out. Opening the waterproof case for the charge controller revealed that the Velcro backing on the controller had come loose and the controller was resting face down on the other equipment in the box. I don't think that anything had shorted out, and the controller still appeared to be working correctly, although there was no output from the panel. Solar panels are capable of operating with a short circuit between their outputs, it's actually a rating that they are specified for: "short-circuit current". So I'm not exactly sure what happened. I contacted the panel vendor to see about replacement, but have not heard back yet.

Up until now, I have been using my iPhone in AMOS as a hotspot, whenever cell connectivity was required. It never actually worked very well. Even though my phone was right inside AMOS, it would often drop the connection, requiring a reset of either the phone or AMOS to get re-established. So last week I bought the Huawei LTE E8372 Hotspot Turbo Stick: https://www.thesource.ca/en-ca/cell-phones/portable-internet/huawei-lte-e8372-hotspot-turbo-stick/p/108036412 I was able to use the same 100 MBytes data plan that I had for the Android phone. So far I have just done some limited testing with it, but it seems to work well. It's also pretty small and plugs into one of the available USB charging ports on the charge controller. I'll have to try it out in an actual field test soon.

The turbidity sensor enclosure is coming along, but so far isn't quite 100% waterproof. The weak point now is near the top, where the cable enters the housing. I hung an old lawnmower spark plug from the bottom of it to weigh it down and make it more vertical in the water, and by taking up some of the slack in the electrical cable I can keep the top end from getting immersed in the water. It's not ideal, but might work OK for now.

Software-wise, things are coming along also. I modified the startup code to make sure that a GPS fix is acquired prior to saving sensor data. Previously, AMOS would wake-up from sleep mode to collect data, but GPS data was not always available before the sensor data was collected. I also added code for better handling the low battery condition. Now if the battery voltage dips below 11.3 V an alarm can be sent via email and / or text, and AMOS goes into low power mode for an hour, in the hope that some exposure to sunlight will give it some more charge.