A C library to communicate with the LEDs and sensors on the Raspberry Pi
Sense Hat.
Copyright (c) 2017 BitBank Software, Inc. written by Larry Bank bitbank@pobox.com
The reason for 'unchained' is that the Sense Hat is often assumed to be an accessory which only works on RPI hardware with RPI provided software. In actuality, the Sense Hat is just a collection of I2C devices that can work with any computer which has an I2C bus. The purpose of this library is to provide a simple example of how to work with the Sense Hat without needing any special software. The code here is not complete in that it doesn't expose all modes/options of the sensors. It does provide a minimal example of how to initialize and read data from them. I have tested the Sense Hat on Raspberry Pi computers (1B/3B/ZeroW) and Orange Pi boards.
Aug 20 2024
Copyright (c) 2023-2024 TC Wan
Updated for SenseHat kmod support found in most recent kernels.
Tested with Ubuntu 24.04 on RPi 5 (should be able to autodetect LED Matrix and Joystick on RPi 4 as well).
This library assumes that the LED Matrix is mapped to /dev/fbX and the Joystick is mapped to /dev/input/eventX
The autodetect logic came from the Astro-Pi Python code.
In order to program the SenseHat with Ubuntu, you will need to configure Ubuntu as follows:
(This is needed for Ubuntu 24.04)
$ sudo vi /boot/firmware/config.txt
[all]
# Force RPi SenseHat Detection
dtoverlay=rpi-sense
To avoid having to run the program using sudo, we enable global access to the i2c device.
$ sudo vi /etc/udev/rules.d/99-i2c.rules
KERNEL=="i2c-[0-7]",MODE="0666"
These drivers take over the I2C bus and prevents the library from talking to the devices directly.
$ sudo vi /etc/modprobe.d/blacklist-sensehat-industrialio.conf
blacklist st_magn_spi
blacklist st_pressure_spi
blacklist st_sensors_spi
blacklist st_pressure_i2c
blacklist st_magn_i2c
blacklist st_pressure
blacklist st_magn
blacklist st_sensors_i2c
blacklist st_sensors
blacklist hts221_i2c
# Don't blacklist industrialio as it is used by other drivers
# blacklist industrialio_triggered_buffer
# blacklist industrialio
To check that the SenseHat is accessible via I2C at the default addresses.
See SenseHat Info.
$ sudo apt-get install i2c-tools
$ i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- 1c -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- UU -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- 5c -- -- 5f
60: -- -- -- -- -- -- -- -- -- -- 6a -- -- -- -- --
70: -- -- -- -- -- -- -- --
UU: Reserved by kernel drivers (rpisense_fb, rpisense_js, rpisense_core)