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This page describes experiments in communicating between a [Raspberry Pi] (as a master) and an [Arduino] (as a slave) over [I2C]. The Raspberry Pi is programmed in [Python], the Arduino using a sketch (the Arduino's own language).
This page describes experiments in communicating between a [Raspberry Pi] (as a master) and an [Arduino] (as a slave) over [I²C]. The Raspberry Pi is programmed in [Python], the Arduino using a sketch (the Arduino's own language).
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I based this experiment on an article found on ''The Robotics Back-End'' (see References below), but have modified it to use Python rather than C on the Raspberry Pi, since that's the main language I've been using to write the operating system of the [KR01] robot.
I based this experiment on an article found on ''The Robotics Back-End'' (see References below), but have modified it to use Python rather than C on the Raspberry Pi, since that's the main language I've been using to write the operating system of the [KR01] robot. Some of the ideas I found online tended to lock up the I²C bus or cause other kinds of problems. When I stumbled onto an example using the WiringPi library things seemed to even out.
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[WiringPi-Python|https://github.com/WiringPi/WiringPi-Python] library. This can be installed via:
[WiringPi-Python|https://github.com/WiringPi/WiringPi-Python] library. In particular, I tried using the {{wiringPiI2CRead()}} and {{wiringPiI2CWrite()}} methods. For documentation, see [The I²C Reference Library|http://wiringpi.com/reference/i2c-library/].
It should be noted that the I²C read and write methods send a single integer. In order to communicate
strings or other data, you'll need to serialise the data and then deserialise it on the other end.
For an example, see: [How do I serialize a Python dictionary into a string, and then back to a dictionary?|https://stackoverflow.com/questions/4342176/how-do-i-serialize-a-python-dictionary-into-a-string-and-then-back-to-a-diction]
In the end I developed a solution called __[pimaster2ardslave|https://github.com/ifurusato/pimaster2ardslave]__ that has been posted as a project on github, which includes a Raspberry Pi Python 3 script
and an Arduino sketch.
I found to my consternation that the ''Arduino Nano BLE Sense'' that I bought for the purpose of being used as
the slave processor __can't be used as a slave__: the Wire library it uses hasn't implemented the I²C slave protocol, though this is not documented anywhere (I found this out on the Arduino forum). One of the benefits of the Nano BLE Sense was that it's a 3.3V device, whereas the regular Nano is 5V. I'm still searching for the right
[Arduino] board now... (😠) maybe I'll use a Teensy or an Adafruit board.
!! Raspberry Pi Installation
WiringPi for Python can be installed via:
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!! Arduino Installation
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* [WiringPi|http://wiringpi.com/] (C++ library)
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* From Raspi.TV an article on __WiringPi2__ (really only the first is relevant here):
** [How to use WiringPi2 for Python on the Raspberry Pi in Raspbian part 1|https://raspi.tv/2013/how-to-use-wiringpi2-for-python-on-the-raspberry-pi-in-raspbian]
** [How to use WiringPi2 for Python with pull-ups or pull-downs and PWM – pt 2|https://raspi.tv/2013/how-to-use-wiringpi2-for-python-with-pull-ups-or-pull-downs-and-pwm]
** [Using the MCP23017 port expander with WiringPi2 to give you 16 new GPIO ports – part 3|https://raspi.tv/2013/using-the-mcp23017-port-expander-with-wiringpi2-to-give-you-16-new-gpio-ports-part-3]
* [Using I2C to connect two Arduino Nanos|https://sandervandevelde.wordpress.com/2015/10/13/using-i2c-to-connect-two-arduino-nanos/], blog post by Sander van de Velde
* [i2c SLAVE|https://github.com/adafruit/circuitpython/issues/437] on Adafruit's CircuitPython forum
* [Raspberry Pi - Arduino Serial Communication|https://www.instructables.com/id/Raspberry-Pi-Arduino-Serial-Communication/]
* [Raspberry Pi (master) Arduino (slave) I2C communication with WiringPi|https://roboticsbackend.com/raspberry-pi-master-arduino-slave-i2c-communication-with-wiringpi/], from ''[The Robotics Back-End|https://roboticsbackend.com/]'' ("Program Robots Like a Boss")
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! Arduino
* [Master Reader/Slave Sender|https://www.arduino.cc/en/Tutorial/MasterReader]
* [Master Writer/Slave Receiver|https://www.arduino.cc/en/Tutorial/MasterWriter]