You’ll probably want to keep the batteries either all in series or all in parallel to keep them charged correctly. I haven’t done a lot of work with batteries, but what I’ve seen seems to have them either all in parallel or all in series. There’s a pretty similar circuit here…[Read more]
I don’t have any current active projects, I’m pondering an open source lagrangian drifter for stream flow measurements, but nothing build yet. You’ve written up some nice installation instructions to keep in mind.
That’s a great summary of things. Doing both sides of the link is both an advantage and disadvantage for these approaches. There’s also no re-occurring charges for service, although the up-front cost is probably higher.
This is independent of a cellular carrier, you use unlicensed ISM bands for communications. You can sort of think of this as very long distance Wifi. The sensors communicate with a separate base station that you configure. The Datarates you can get over this are somewhat dependent on the distance between the sensors and the base…[Read more]
One technology that’s become recently available is LoRa, which is a ISM (900 MHz) band system that’s optimized for data transmission. More details at https://www.lora-alliance.org/ but PCB’s with LoRa radios on them are available from Tindie.com at reasonable pricing (sub $20 ish). It looks like these would require a base station to complete a…[Read more]