An important hat for our makerspace is the Sense HAT. This page summarizes it's features and use.
The Raspberry Pi is in itself a great device capable of many things. Given it has such a small size, it is portable and can connect immediately to the Internet, we can do many projects out of the box. It can be further enhanced with sensors and electronics gadgets to interact with the world - via it's GPIO ports.
To extend the features with ready-made gadgets, you can acquire a 'HAT'. HAT stands for 'Hardware Attached on-Top'. A popular and powerful HAT is 'Sense HAT' - a suite of sensors which allow the Raspberry Pi to sense the world around it, including an array of LEDs on top suited for displaying any information. On top a small joystick is attached.
Here is a list of all sensors attached to Sense HAT. As mentioned it also features an 8x8 LED matrix and a mini joystick
In this project, you will make your very own MP3 player using a Raspberry Pi and a Sense HAT. You'll be able to shift between tracks in your playlist, change the volume, and show a cool disco display on the LED matrix. The Basics: DIY HATs. You may have noticed that your RaspPi doesn't include a prototyping area. Jul 12, 2018 The answer is very simple; HATs are designed to work with standard Raspberry Pi computers (such as the Model B 3), while pHATs are designed to work with the Raspberry Pi Zero. If you are interested in recording both positioning and environmental data, the Sense HAT is a famous choice. The Sense HAT is an add-on board for Raspberry Pi comprising of a 8×8 RGB LED matrix, a five-button joystick and the following sensors: Gyroscope, Accelerometer, Magnetometer, Temperature, Barometric pressure and Humidity. All Raspberry Pi HATs & pHATs Look no further for plenty of fantastic options to expand the capabilities of the Raspberry Pi with this great variety of exciting HATs (and pHATs for the Pi Zero)! All these boards are fully compliant to official standards and offer every Maker the chance to apply their Pi to any one of a number of great bespoke.
- Gyroscope
- Accelerometer
- Magnetometer
- Temperature
- Humidity
- Barometric pressure
Please note: this hat together with 2 Pis has gone to space! Please check the Astro Pi Project - a great example of merging education / interest of young students with the British space program. The device below is one of the 2
In order to work correctly, the Sense HAT requires an up-to-date kernel, I2C to be enabled, and a few libraries to get started. Note that my vanilla Raspbian System already included all, but just in case your distro has them missing.
- Update your system
- Install the Sense HAT package which will ensure the kernel is up-to-date, enable I2C, and install the necessary libraries and programs
- [optional] Some authors claim you need also to ensure compatibility with Python 3 by adding the 'Pillow' package
- A reboot may be required if I2C was disabled or the kernel was not up-to-date prior to the install
Installation
In order to work correctly, the Sense HAT requires an up-to-date kernel, I2C to be enabled, and a few libraries to get started.
Ensure your APT package list is up-to-date:
Next, install the sense-hat package which will ensure the kernel is up-to-date, enable I2C, and install the necessary libraries and programs:
Finally, a reboot may be required if I2C was disabled or the kernel was not up-to-date prior to the install:
Hardware
The schematics can be found here.
Software overview
After installation, example code can be found under /usr/src/sense-hat/examples.
These can be copied to the user's home directory by running cp /usr/src/sense-hat/examples ~/ -a.
The C/C++ examples can be compiled by running make in the appropriate directory.
Sense Hat Raspberry Pi Zero Gravity
The RTIMULibDrive11 example comes pre-compiled to help ensure everything works as intended. It can be launched by running RTIMULibDrive11 and closed by pressing Ctrl+c.
Python sense-hat
sense-hat is the officially supported library for the Sense HAT; it provides access to all of the on-board sensors and the LED matrix.
Complete documentation can be found at pythonhosted.org/sense-hat.
RTIMULib
RTIMULib is a C++ and Python library that makes it easy to use 9-dof and 10-dof IMUs with embedded Linux systems. A pre-calibrated settings file is provided in /etc/RTIMULib.ini, which is also copied and used by sense-hat. The included examples look for RTIMULib.ini in the current working directory, so you may wish to copy the file there to get more accurate data.
Other
LED matrix
The LED matrix is an RGB565 framebuffer with the id 'RPi-Sense FB'. The appropriate device node can be written to as a standard file or mmap-ed. The included 'snake' example shows how to access the framebuffer.
Joystick
The joystick comes up as an input event device named 'Raspberry Pi Sense HAT Joystick', mapped to the arrow keys and Enter. It should be supported by any library which is capable of handling inputs, or directly through the evdev interface. Suitable libraries include SDL, pygame and python-evdev. The included 'snake' example shows how to access the joystick directly.
Calibration
Taken from this forum post.
Install the necessary software and run the calibration program as follows:
You will then see this menu:
Press lowercase m. The following message will then show; press any key to start. Stb erom upgrade tool.
After it starts, you will see something similar to this scrolling up the screen:
Focus on the two lines at the very bottom of the screen, as these are the most recently posted measurements from the program.Now you have to move the Astro Pi around in every possible way you can think of. It helps if you unplug all non-essential cables to avoid clutter.
Try and get a complete circle in each of the pitch, roll and yaw axes. Take care not to accidentally eject the SD card while doing this. Spend a few minutes moving the Astro Pi, and stop when you find that the numbers are not changing anymore.
Now press lowercase s then lowercase x to exit the program. If you run the ls command now, you'll see a new RTIMULib.ini file has been created.
In addition to those steps, you can also do the ellipsoid fit by performing the steps above, but pressing e instead of m.
When you're done, copy the resulting RTIMULib.ini to /etc/ and remove the local copy in ~/.config/sense_hat/: Arcview gis mac free download.
Pizzicato strings garageband mac. You are now done.
Updating the AVR firmware
..
EEPROM data
These steps may not work on Raspberry Pi 2 Model B Rev 1.0 and Raspberry Pi 3 Model B boards. The firmware will take control of I2C0, causing the ID pins to be configured as inputs.
Enable I2C0 and I2C1 by adding the following line to
/boot/config.txt:Enter the following command to reboot:
Download and build the flash tool:
Reading
EEPROM data can be read with the following command:
Writing
Sense Hat Raspberry Pi Zero W
Please note that this operation is potentially dangerous, and is not needed for the everyday user. The steps below are provided for debugging purposes only. If an error occurs, the HAT may no longer be automatically detected.
Raspberry Pi Ssd Hat
Download EEPROM settings and build the
.eepbinary:Disable write protection:
Write the EEPROM data:
Re-enable write protection:
