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RF UART, help selecting which one — Parallax Forums

RF UART, help selecting which one

evanhevanh Posts: 17,261
edited 2026-05-30 10:02 in Accessories

I'm about to try building my own hot water solar diverter. I've got a dead unit sitting beside me right now that cooked itself after about 10 years of operation. I've already tried repairing it but it died again after a few days of partial operation. It was fancy in that it did full smoothed modulation. Has quite a number of large inductors in it. I'm not going to attempt to replicate that. Instead I'll start with just using the existing current transformer that's still attached to the main cable from the power meter outside the house. I have it shorted. I just want to automatically control when the water heat is turned on and off. Rough plan is when export power reaches 1.8 kW turn it on, and when import power reaches 1 kW turn it off. It's a 2kW heater element.

I figure it's best to not run a data cable around the house and especially into the water heater wiring. With that in mind it seems a good idea to use a RF link of some sort. I want to be able to have rapid debugging feedback with it in circuit so I can quickly experiment with software changes. The Propellers are at home with UART serial port so I figure it's easiest to stick to that. The distance is only down the hallway, so a couple of rooms away tops.

As a first guess I'm thinking Bluetooth is the obvious choice. Or is there other more suitable options?

Looking up general info on Bluetooth I'm immediately swamped with versions and then BLE seems to be a whole new thing. My best guess is I can probably choose an old simpler, say v4, Bluetooth module for the remote device (Solar Diverter) and still be able to buy the latest USB BLE adaptor for the development computer and have them talk ... right?

Comments

  • @evanh said:
    Looking up general info on Bluetooth I'm immediately swamped with versions and then BLE seems to be a whole new thing. My best guess is I can probably choose an old simpler, say v4, Bluetooth module for the remote device (Solar Diverter) and still be able to buy the latest USB BLE adaptor for the development computer and have them talk ... right?

    That is asking for problems: https://superuser.com/questions/1510761/are-all-bt-4-5-dongles-compatible-ble
    why not use an ESP C6/C5 they are not that much more expensive then pure BT adapters and allows you to choose WIFI or BT or ...

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