The RFM69CW radio module by HopeRF is a compact, powerful radio transceiver module for swapping data packets in the 868 MHz ISM band, using standard and enhanced FSK modulation. Great for sub-compact designs; just 4mm of mounted height from using an SMD precision crystal. They are physically and pin compatible with the RFM12B radios now on JeeLabs products. We expect to migrate most products to the RFM69 in the coming months.
The JeeLabs library, JeeLib now includes a compatibility mode for RFM69 and the radios are 100% compatible with existing RFM12B modules and radios (of the same frequency).
Though consuming a similar level of power, the RFM69CW receiver section can decode fainter signals than the classic RFM12B. The transmitter section *maximum* output power is +13dBm, considerably higher than the +5dBm of the RFM12B. The current drain at these (adjustable) higher power settings is correspondingly higher. With the better receiver sensitivity, many applications will not need to use the higher transmit power settings, potentially saving on battery life.
Comparing like-with-like, pairs of modules will generally have greater range and/or better penetration of walls/ceiling than when using pairs of the classic RFM12B. The range of the new radios at full power should be in the 200-300m range, instead of the ~100m for the RFM12B. Range varies by frequency and through walls and floors of course.
The physical module is compatible with the PCB footprint on all current JeeNodes and JeeLinks. For details of the fast-evolving level of software support, see this Forum topic in the JeeLabs forum.
Control is via a fast SPI bus with reduced MPU loading. The recommended power supply range of 1.8 < Vdd < 3.6 V can squeeze almost the last energy out of depleting batteries without needing a boost converter.
N.B.: An antenna must be connected to the module. A quarter wavelength wire – 82mm for 868 MHz -can be used (not included). Operation for extended periods without an antenna at the higher transmitter power levels risks permanent damage to the output stage of the radio.
Typically the 915 MHz ISM band has better penetration of light obstacles such as plaster walls and ceilings plus this band is often less crowded than the 434 band we also stock, but you may need a different band for compatibility with other equipment such as weather stations. JeeLabs stocks an 868 MHz version of these modules with EU prices.
Marking Convention: a red spot on the top of the transceiver chip indicates optimized for the 915 MHz ISM band, a green spot for 433 MHz. The bronze spot diagonally opposite marks a successful module test before shipping. This final check helps to avoid the known problem of occasional infant mortality with this class of RF module. You can have confidence that you are building your project with a fully functional module!
Features of the radio lacking on the RFM12B:
- OOK support via 1 pin
- RSSI (received signal strength indicator) with software support
- +13db send power
- increased receive sensitivity
- more parameters are accessable in software