The family: classic, C6, and C3. Same firmware, same job, three sizes.
Microcontroller
An ESP32 board
The little computer that runs OAT firmware. It listens, reads, and pushes data to a place you own, all day, on a few dollars of electricity a year.
Three sizes, one job. Every board here runs the same firmware and does the same work in every OAT solution. The classic is the big familiar one, the C6 is the newest, the C3 is the small value pick. Pick by price and what is in stock the day you order; you cannot pick wrong.
Where to get one
These are searches, not endorsements. OAT sells nothing and earns nothing when you buy; the search term is the know-how.
ESP32 (classic)
AmazoneBayAliExpress
Specs.
| Radios | Wi-Fi plus Bluetooth on every board in the family |
|---|---|
| Power | USB, about a watt; any phone charger runs it around the clock |
| Firmware | Every OAT sketch runs on every board here; flash from the browser where the sketch is live |
| Wired sensors | Reads I2C and 1-Wire probes directly on its pins (SHT-30, DS18B20, and kin) |
How to pick a good one.
- Any listing showing a USB port and two rows of pins is right. That is the whole spec.
- Avoid the bare postage-stamp module with no USB port: that one needs a programmer.
- Brand does not matter much. Espressif makes the chip in the middle; dozens of makers put it on a board, and the firmware runs on all of them.