All About Circuits have a good, simple tutorial by Benjamin Crabtree that uses the “hello world” equivalent of LEDs – blinking them to indicate ‘message received’ – to walk users through the RFM69HW transceiver module. Because the module is a transceiver, capable of both transmitting and receiving signal, the project requires two identical builds to perform the tutorial, and can be easily adjusted in code to understand specific premises of transmission and reception. Check it out here.
Engineers are designing more and more circuits that make use of some form of wireless communication to achieve a level of convenience and connectivity not feasible with wired options. In the designer’s quest to go wireless, a few options present themselves which perform different features. 2.4GHz transceivers can send and receive large amounts of data and can operate with very small antennas, but they suffer from a comparatively short range with regard to lower frequency transceivers as well as a level of complexity and cost that might be overkill for many projects. For projects where low throughput is acceptable, the RFM69HW series transceivers provide a less complex solution which can interface with everything from the humble PIC up to a modern desktop PC and everything in between. The RFM transceiver can be purchased in 433MHz, 868MHz, or 915Mhz license-free ISM band for about $4, and can operate using FSK, GFSK, MSK, GMSK and OOK modulations. The power consumption is extremely low, yet these transceivers can communicate over several hundred meters given adequate antennae. These features make this device an excellent candidate for adding wireless connectivity to battery powered or remote projects for a very low cost investment. This project will be part one of a series introducing a range of applications for the RFM transceivers; in this case we will be setting up the transceivers to wirelessly enact the time-honored embedded systems equivalent of “Hello World!”- the “Blinky” program.
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