Description: This is the SparkFun RFM69 Breakout, a small piece of tech that breaks out all the pins available on the RFM69HCW module as well as making the transceiver easy to use. The RFM69HCW is an inexpensive and versatile radio module that operates in the unlicensed ISM (Industry, Science and Medicine) radio band. It’s perfect for building inexpensive short-range wireless networks of sensors and actuators for home automation, citizen science and more.
This RFM69HCW operates on the 915MHz frequency and is capable of transmitting at up to 100mW and up to 300kbps, but you can change both of those values to fit your application. For example, you can maximize range by increasing the transmit power and reducing the data rate, or you can reduce both for short-range sensor networks that sip battery power. At full power and with simple wire antennas, the RFM69 breakout can get messages from one side of a large office building to the other through numerous internal walls. In open air you can reach 500 meters or more. With more complex antennas and modulation schemes, similar parts have successfully transmitted from space to the ground (by very smart amateur radio enthusiasts; your mileage may vary)!
The RFM69HCW uses an SPI (Serial Peripheral Interface) to communicate with a host microcontroller, and several good Arduino libraries are available. It supports up to 256 networks of 255 nodes per network, features AES encryption to keep your data private, and transmits data packets up to 66 bytes long.
SparkFun sells two versions of the RFM69HCW: this 915MHz version and a 434MHz version. Although the ISM band is license-free, the band itself is different in different areas. Very roughly, 915MHz is for use in the Americas, and the 434MHz version is for use in Europe, Asia and Africa. Check your local regulations for other areas.
Dimensions: 0.8" x 1.1"
Based on 6 ratings:
1 of 1 found this helpful:
Used a simple 78mm wire antenna, bread-boarded a pair to check range and got 300 meters from my co-workers desk inside the office to a location in the cemetery nearby. (Clear day, good weather.) Some obstacles were in the line of sight, cars, leafy trees, etc. At 300 meters the RSSI was -90 to -100 when held 2+ feet off the ground. Didn’t bother walking any further. Sitting on the ground the signal was lost. It was clearly reaching the end of the range given the obstacles. Keeping the unit up off the ground made an important difference.
At shorter distances obstacles such as dumpsters, buildings, concrete pillars and foundations did not prevent the signal from getting through.
Didn’t invest any time trying to squeeze more range out.
Comments from others specific approaches/applications and range achieved would be great to see.
1 of 1 found this helpful:
I purchased this module for an industrial project and tested it in very harsh environment with so much electrical noise and it works excellently without dropping a single packet upto 150 meters with normal wired antenna. May be work more than 150 meters with proper physical antenna.
The layout of the antenna (A) connection and 2 surrounding ground connectors (G and GND) make it easy to attach an edge-mounting SMA connector for an external antenna.
I needed a sentinel that was about 350 feet away and did not want to have a network to get it.
These modules are incredibly easy to use. Just load the driver and plug in the parent and child ID’s. That’s it! And it’s a quarter of the cost of XBee, which requires an overly complicate setup procedure using a separate program (XCTU). I will be using these in all of my future radio based projects.
Using the referenced LowPowerLabs RFM69 library on Arduino Pro Mini 3.3V. Setting the RFM69 to sleep mode drops my current measurement from about 15mA (in its receive mode) to about 120 micro amps. The spec sheet section 2.3.1 Power Consumption says the maximum power draw in sleep is “1 uA” which I believe means one microAmp. This makes a difference to my application running my project on a pair of AA lithium batteries. For now, the RFM69 accounts for more than half the “everything powered down and sleeping” idle current on my assembly.
I am beginning to believe the spec is a typo. It makes sense if the spec was milliAmps instead of microAmps. I am getting the “typical” sleep current in that case.