Here is the breakout board for the RFM22B which gives you access to the pins. The RFM22B is a low-cost ISM (industrial, scientific, and medical) FSK (frequency-shift keying) transceiver module which offers communication at 434MHz and adjustable output power of up to +17 dBm. The wide operating voltage range of 1.8–3.6 V and low current consumption makes the RFM22 an ideal solution for battery powered applications.
Communication with the RFM22B is achieved via a standard 4-wire SPI interface. Three configurable general purpose I/Os are also available, the use of which can be tailored towards the needs of your project. A host of other features are also available including an 8-bit ADC, temperature sensor, RX and TX FIFOs, and low-battery detection. See the datasheet below for a complete description of every register and command.
In our testing, a 17cm wire attached to the ‘ANT’ pin worked just fine. A hole is drilled next to the ‘ANT’ pin for strain relief.
- Frequency Range = 434 MHz
- Sensitivity = -118 dBm
- +17 dBm Max Output Power (Configurable)
- Low Power Consumption
- Data Rate = 1 to 128 kbps
- Power Supply = 1.8 to 3.6 V
- Ultra low power shutdown mode
- Digital RSSI
- Auto-frequency calibration (AFC)
- Configurable packet structure
- Preamble detector
- TX and RX 64 byte FIFOs
- Low battery detector
- Temperature sensor and 8-bit ADC
- -40 to +85 °C temperature range
- Integrated voltage regulators
- Frequency hopping capability
- FSK, GFSK, and OOK modulation
- Low BOM
- Power-on-reset (POR)
Dimensions: 0.63x0.63in (16x16mm)