Wireless communication between Raspberry Pi and Arduino

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Wireless communication between Raspberry Pi and Arduino Gerrit Niezen @gendor

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Wireless communication options Cost Range Rate WiFi £7 (Amazon UK) 100+ feet 150Mbps Bluetooth £3 (ModMyPi) 60+ feet 3 Mbps Cellular £30 (Amazon UK) Coverage dependent 7 .2 Mbps Satellite £159 + tax (Rock Seven) Anywhere on earth outside 140 bps RFM12B (868 MHz) £5 (£16 for 2 + Arduino kit) 300+ feet 115.2 kbps

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RFM12B Quasar 868MHz RF Transceiver Module (Maplin) HopeRF Alpha RF

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Module frequencies and antenna length 433MHz (worldwide) - 165mm of wire 868MHz (Europe) - 82mm of wire 915MHz (USA & Australia only)

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Why RFM12B Longer range than WiFi and Bluetooth Can talk to home automation equipment, e.g. thermostats, ﬁre systems, burglar alarms Cheaper to talk to Arduino ?

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JeeLabs RFM12B 868 MHz SMD Module €6 RFM12B 868 MHz Board €11.50 Shipping €2.50 Total €20

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Arduino connections 5V -> 5V GND -> GND SCK -> 13 SDO -> 12 SDI -> 11 SEL -> 10 IRQ -> 2 3V3 -> NC

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Raspberry Pi connections P1/17 -> VDD (+3.3V) P1/19 -> SDI P1/21 -> SDO P1/22 -> nIRQ P1/23 -> SCK P1/25 -> GND P1/26 -> nSEL https:/ /www.modmypi.com/blog/raspberry-pi-gpio-cheat-sheet Useful!

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Some Linux kernel hacking Clone/download the repository Edit rfm12b_config.h Run make to build the kernel driver sudo modprobe spi-‐bcm2708 sudo insmod rfm12b.ko https://github.com/gkaindl/rfm12b-‐linux

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rfm12b_config.h #define RFM12B_BOARD 1 #define RFM12B_DEFAULT_GROUP_ID 211 #define RFM12B_DEFAULT_BAND_ID 2

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Check that the kernel driver is loaded Output from dmesg:  [ 1480.735040] rfm12b: added RFM12(B) transceiver rfm12b.0.1  [ 1480.735145] rfm12b : driver loaded. ! ! ls /dev: rfm12b.0.1

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Get them to talk! On Arduino, use the JeeLib library:    https://github.com/jcw/jeelib/archive/ master.zip Run pingPong example, or  arduino/rfm12b_echo_client in driver directory On Raspberry Pi, in examples/ directory: Run make Run sudo bin/rfbm12b_echo

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Useful links http://jeelabs.net/projects/jeelib/wiki JeeLabs Shop  http://www.digitalsmarties.net/ http://openenergymonitor.org/emon/node/271 Comparison with Digi XBee, Ciseco XRF  http://blog.homelabs.org.uk/wireless-‐ connectivity/ http://jeelabs.net/projects/hardware/wiki/ RFM12B_Board

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Raspberry Pirate Radio http://makezine.com/projects/ raspberry-‐pirate-‐radio/

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Swansea Hackspace http:/ /swansea.hackspace.org.uk @SwanseaHack

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Images used under the Creative Commons license: _DSC6307 by FITLab Swansea on Flickr hopjes candy = coffee ﬂavored! by yosoynuts on Flickr RFM12B-S2 Wireless Transceiver - 915MHz by SparkFunElectronics on Flickr Piratey potrace by J.J. on Wikipedia ! Arduino from Fritzing - http://fritzing.org Icons from Font Awesome by Dave Gandy - http://fontawesome.io