*Not actually in space yet. Wait till December.
Today we have a new product launch: the Sense HAT is now available from the Swag Store, and through our partners RS Components and Premier Farnell/CPC. Here’s a video from Matt Timmons-Brown, freshly released from GCSE exam hell, to show you around.
The Sense HAT was originally developed around James Adams’ idea to make a cool toy-style board that showed off just how much you could do with your average modern MEMS gyroscope, 64 RGB LEDs and some Atmel microcontroller hackery.
Somewhere between prototype and production, it seems to have attracted extra features like a pressure sensor, a humidity/temperature sensor and a teeny joystick. It also seems to have been comandeered and made an integral part of the Astro Pi mission, which will see two Raspberry Pis, two Sense HATs and a lot of code written by UK schoolkids hosted on the International Space Station – I guess I’m to blame for that.
The board forms the basis for many of the experiment sequences that will be run on the ISS – many of the schools competition winners’ entries made good use of the HAT’s sensors to gather their experimental data. The LED matrix also provides a feedback mechanism and interactivity for Major Tim Peake when he’s tasked with deploying the Astro-Pi board on the ISS (he’ll be setting it up on-orbit to run the experiment sequences). One of the winning entries – Reaction Games – programmed a whole suite of joypad-operated games played via the LED matrix. Snake is hilarious on an 8×8 screen.
The board itself has a suite of sensors, a “D-pad” style 5-button joystick and an 8×8 RGB LED matrix driven by a combination of an LED driver chip and an Atmel AVR microcontroller – an ATTiny88.
For the terminally curious, here are the schematics of the board.
Here’s the hardware run-down:
Pressure / Temperature
Humidity / Temperature
All of these sensors have features for periodic sampling of sensor values – complete with internal FIFO storage. The LPS25H and HTS221 have maximum sample rates of 25 per second, the LSM9DS1 has a maximum sample rate of 952Hz – we are already imagining the birth of a million Pi-controlled stunt quadcopters.
All of the sensors (and the base firmware for the Atmel) are accessible from the Pi over I2C. As a fun bonus mode, the SPI peripheral on the Atmel has been hooked up to the Pi’s SPI interface – you can reprogram your HAT in the field! We use this method to get the firmware into the Atmel during production test – and we leave it unprotected so you can substitute the stock firmware to get it to do whatever you want. Seriously. First person to turn this sensor HAT into a quadcopter controller HAT wins a cookie from me.
To access the magic, simply enter:
sudo apt-get update sudo apt-get install sense-hat sudo pip-3.2 install pillow
into a terminal window. Note you will have to reboot for the Sense HAT to be recognised.
The API is well-documented (and tested extensively by schoolchildren as part of Astro-Pi) – get reading here.
The LED matrix appears as a Linux framebuffer device – for fun you can compare the results of
cat /dev/urandom > /dev/fb0
cat /dev/urandom > /dev/fb1
to fill either your attached monitor or the LED matrix with random noise. The joypad appears as a standard input device – the “keys” map to Up/Down/Left/Right and Enter.
The baseline price (excluding spacers and screws, and local taxes) is $30. You’ll be able to buy from all the usual suspects – the Swag Store (which is bundling spacers and screws for free), RS Components/Allied, Premier Farnell/Newark and all their subsidiaries have stock today. Secondary suppliers may take a couple of days to get their hands on stock.
So, what are you waiting for? Get sensor hacking!
Wednesday, August 26, 2015
Buy the Sense HAT – as seen in space*!
at 1:00 AM