[Johan Kanflo] sent us his latest recipe: a blend of one part RFM69 sub-gigahertz radio transceiver with one part ESP8266 module. The resulting dish looks absolutely delicious!
We’re all charmed with the ease of use that the ESP8266 brings to the table — plug it in and you’re talking to your existing WiFi network — but we hate the power consumption for battery-powered applications. WiFi is a power hog. And although ISM-band radio modules make point-to-point communications cheap and power-saving, getting them to talk with your computer takes an adapter.
So [Johan] combined the two radios and made a sweet ISM-radio-to-WiFi bridge. His demo application takes whatever data is sent over the ISM band and pushes it to an MQTT broker on his WiFi network. Hardware and firmware are up on GitHub.
We’ve been wanting a device like this for our home network for a while now. Kudos, [Johan] for making it so easy!
While cruising the Internet one day, [Raj] found a really cool pair of RF transmitters and receivers manufactured by Dorji Applied Technology. These modules – the DRF5150S and DRF4432S – work just like any other ISM band transmitter receiver pair with the addition of inputs for analog and digital input pins. [Raj] put together a tutorial for using these radio modules, perfect if you need a very simple wireless connection for your next project.
[Raj]’s tutorial for using the Dorji sensor modules shows the transmitter has two operating modes. The first mode is a simple data transmitter, connected to a microcontroller through a UART connection. The ‘sensor’ mode doesn’t require a separate chip; the on-board STM8L151 microcontroller reads analog values on two pins and sends them over the air to the DRF4432S receiver module.
After programming the transmitter to function as a wireless sensor with an app released by Dorji, [Raj] plugged the transmitter into a breadboard with a battery and digital thermometer. The receiver module is plugged into a USB -> UART module, and data is pulled down from the sensor in a terminal.
[Raj] wrote a small app in Processing to display the data coming from the sensor. He has a wonderful animated thermometer showing the temperature reading of the sensor, the battery voltage and the strength of the wireless signal. Pretty easy, and a very helpful tutorial if you need an easy way to build a wireless sensor.