The JeeLabs Shop

The RFM12B radio module by HopeRF is a compact wireless radio module for sending and receiving packets on the 868 MHz ISM band using FSK. 

There are two variants, the -S1 series with a metal can crystal and the more expensive -S2 type using a low profile, SMD crystal. We supply both the height-saving SMD crystal type and the metal can crystal - the latter is useful for compatibility if you are extending an existing network using this type of crystal. Both types interoperate fine - you may need to adjust the crystal offset for best reception when mixing the types.

The RFM12B is offered as standard on JeeNodes and JeeLinks. It is controlled via the SPI bus, and works with a power supply level of up to 3.8 V.

An antenna must be connected to the module – for 868 MHz, an 82-mm piece of wire can be used (quarter wavelength).

For more information, see HopeRF’s RFM12B specification. For details on how to hook it up and an Arduino library with sample C code, see this post on the JeeLabs daily weblog.

For a breakout board for this module with a 5V option, see the RFM12B Board.

The Modern Device shop has 915 MHz modules at US$ prices.