A Moteino is an ATMega328 with the Arduino bootloader and HopeRF RFM69 radio on board, everything running at 16MHz and 3.3V. I could deploy battery powered end devices that run for months from a coin cell like my door sensor or backed by a solar panel like in my weatherstation.Ī year ago I started playing with LowPowerLab's Moteinos as a replacement for the XBee network. XBees are fairly expensive, hard to configure but also pretty powerful and full featured. I want you to focus on the “Xbee MQTT Client” in the previous image. This is the story of one of those gateways. Most of them have been replaced by Node-RED nodes. The picture below is from one of my firsts posts about my Home Monitoring System, and it shows some components I had working at the time.Īll those gears in the image are those translators, sometimes called drivers, sometimes bridges, sometimes gateways. The publisher-subscriber pattern gives the flexibility to work on small, replaceable, simple components that can be attached or detached from the network at any moment. Over this time is has gone through some changes, like switching from a series of python daemons to Node-RED to manage persistence, notifications and reporting to several “cloud” services.īut MQTT talks TCP, which means you need some kind of translators for other “languages”. Check your local regulations for other areas.Some 3 years ago I started building my own wireless sensor network at home. The technology I used at the moment has proven to be the right choice, mostly because it is flexible and modular. Very roughly, 915MHz is for use in the Americas, and the 434MHz version is for use in Europe, Asia and Africa. Although the ISM band is license-free, the band itself is different in different areas. SparkFun sells two versions of the RFM69HCW: a 915MHz version and this 434MHz version. 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. The RFM69HCW uses an SPI (Serial Peripheral Interface) to communicate with a host microcontroller, and several good Arduino libraries are available. 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)! In open air you can reach 500 meters or more. At full power and with simple wire antennas, we can get messages from one side of a large office building to the other through numerous internal walls. 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. This RFM69HCW operates on the 434MHz 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. It's perfect for building inexpensive short-range wireless networks of sensors and actuators for home automation, citizen science and more. The RFM69HCW is an inexpensive and versatile radio module that operates in the unlicensed ISM (Industry, Science and Medicine) radio band. 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.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |