Another module of my alarm interface is done. I picked up a 3×4 matrix keypad from Adafruit (http://www.adafruit.com/products/419) But couldn’t find any good python code examples for it’s use. I was able to find a few examples that lead me down the right path in terms of scanning rows first as inputs and then swaping pins to scan the columns. I wrote two libraries, the first just uses 7 of the Raspberry Pi’s GPIO pins then I also wrote one that works for the MCP23008 chip since I’m really in a mode of saving pins when I can Then also just wrote a demo script to show calling the libraries and their use.
Here is the code as it stands now, I have some ideas on how to change it to be better but this is fully working for now.
Membrane 3×4 Matrix Keypad + extras – 3×4 – Punch in your secret key into this numeric matrix keypad. This keypad has 12 buttons, arranged in a telephone-line 3×4 grid. It’s made of a thin, flexible membrane material with an adhesive backing (just remove the paper) so you can attach it to nearly anything. (read more)
BMP085 Barometric Pressure/Temperature/Altitude Sensor- 5V ready - This precision sensor from Bosch is the best low-cost sensing solution for measuring barometric pressure and temperature. Because pressure changes with altitude you can also use it as an altimeter! The sensor is soldered onto a PCB with a 3.3V regulator, I2C level shifter and pull-up resistors on the I2C pins.
NEW! We now have a fully 5V compliant version of this board – a 3.3V regulator and a i2c level shifter circuit is included so you can use this sensor safely with 5V logic and power
Detect particles and/or make a cool random number generator with this handsome Geiger counter kit. This easy-to-make pack of parts turns a simple Geiger-Muller tube (included) into a portable blink, beeping radiation detector. You can also connect an FTDI friend to the header, to get serial output for datalogging on your computer.
Here’s a picture of a project I recently completed: a thermostat for controlling the temperature in a homebrew kegerator. I am using a small chest freezer which can hold two cornelius kegs and associated CO2 tank. I could have spent the $ to just buy a nice digital one, but I had some parts on hand and picked up a few parts from Adafruit and pieced it all together for much less.
The EL Pinwheel was a CUBICAL90 digital art project at Artisan’s Asylum by Scott Janousek. The project was inspired by Ecco Pierce who does metal sculpture and EL. The EL Pinwheel was created in the span of a few hours, in intervals, over the span of a week.
I love the new e-paper offered by Pervasive Displays and sold by Adafruit. They are a bit tricky to get started with however. By default, they only display images, no text or standard graphics calls like “line” and “circle” and each image takes a lot of memory. Too much for a stand alone Arduino UNO.
Even if you have the memory, another tricky thing about them is getting an image to look good in pure black and white (no greys).
At WyoLum, we have tackled all of these problems and figured out how to display UNICODE chars, and draw graphics (lines and circles). We’ve chosen to use an SD card as both a file source and a screen buffer. It is working well. Most of this is just in test code state, but we figure there are others out there struggling with the same issues and might find our solutions handy.
Ever since the Kindle eReader came out, we’ve been wanting a nice small graphical eInk display that is easy to use with a microcontroller. And finally our desires have been fulfilled with the rePaper 2.7″ development board from Pervasive Displays! We’re excited to offer this very interesting display breakout for hackers who want to start playing with small eInk displays.
For the compass rose, I stitched the Adafruit neopixels together and hooked them up to the Adafruit Flora. Also connected to the Flora is a magnetometer/accelerometer. The magnetometer probably gave me the most grief. It turns out that if you want to use communications protocols (like I2C) on e-textiles, make sure the connection is SOLID! I became so frustrated with the magnetometer not talking to the Flora that I just soldered some wires instead.
Despite the frustrations, I’m pretty happy with how the bag turned out. This was also the first time using the Flora and I have to say, I love it! I can certainly tell that the folks at Adafruit put A LOT of thought into it. One little detail that made me really happy was strategically placing the SDA, SCL, power and ground pads so that you wouldn’t have to have any thread/wires cross. If you’ve been working with e-textiles for a while, you’ll know exactly what I mean! Seriously, Adafruit…thank you!!!
The PANdora Box can send one of 16 messages selected by the brass knob connected to a rotary encoder in the center of the base section. The smoky plex allows the various parts within to be seen, aided by an LED strip light of variable color and intensity, and mirrors on the interior walls. Wacky button sounds are played by the Wav shield as the user rotates the brass knob through each message. Pressing the brass knob instructs an Arduino to send the selected Wav file name across the PAN to the remote listeners which then find and play the Wav file, with, or sometimes without, a preamble. The preamble can be selected from a list appropriate to the message, such as creaky doors, or impersonations. The message itself is usually something useful (but not always) like Kids, please take out the garbage.
Each month all San Francisco Fitbit employees are invited to join in a hack night project. This casual event is an opportunity for employees to tinker and participate in various fun projects. The first few hack nights focused on learning to solder using various kits from Adafruit and Sparkfun — some favorites were TV-B-Gone, MiniPOV and Electronic Dice. In another other hack night we added physical feedback to our automated build system. In the case of a failed build a robot voice speaks the engineer’s name and blinky lights are fired off.
Our most recent project was a pair of office thermometers that graph real-time temperature readings using an online data graphing service called Cosm. Indoor office temperature tends to fluctuate throughout the day. Many employees are quite vocal (even dramatic) about their temperature experience, “My blood is boiling, I’m a goner for sure” or “Brrrr, I can’t type, I’m shivering too much”. Temperatures In the mid 70s °F seem to please the most people most of the time.
To get a bit of objectivity on the temperature discussion we decided to provide a reference for each of our two San Francisco locations by having real-time temperature readings posted to a place everyone can see, a web page. If you’re interested in trying something like this yourself, just keep reading.
What is the electric imp? In essence, the Imp provides an easy, integrated way to connect almost any hardware device both to other devices and to internet services. It’s more than just a WiFi card, or even a WiFi module with processing built in – it’s an integrated platform that deals with the drudgery of connectivity, allowing you to concentrate on the application instead of the mechanics.
StockBank is a networked piggy bank with the end goal of collecting enough money to buy one share of the three technology stocks of Google, Apple, and Facebook. As someone drops a coin into the bank, the display shows the amount of the selected stock share price decreasing until it levels off at zero, which means that there is enough money inside the bank to buy one share. The bank then automatically connects to an online broker, purchases the share, and blinks the pig. When the bank is emptied, the counter resets back to another share price and begins the process over again.
The project exists as an open source, networked object that prompts users to stay connected to the current stock valuation of technology corporations and see how they change and fluctuate over time. It reinvents the classic piggy bank by instead of counting money for saving, it connects in real-time to actual stock prices and gives the user an estimate on the amount of money they need to purchase a share of the specified stock.
Coin Acceptor – Programmable 4 Coin Type – Your project may be free-as-in-speech, but that doesn’t mean it has to be free-as-in-beer. This handy coin validator/acceptor module is just like the ones you’ve seen in arcades. This model has the cool ability to accept up to 4 different coins! For example, you can program it for 4 different US coins, or European, or Japanese OR you can have it accept 4 coins from different countries – say a Chinese Yuan, Japanese Yen, American Quarter and European Euro. First you’ll have to program it with what coins you want it to accept. Any coin from 15mm to 29mm in diameter can be used. Each coin is assigned a number of pulses, so for example, a nickel should be 1 pulse, a dime, 2 pulses, a quarter 5 pulses and a half dollar 10 pulses. When a valid coin is inserted, the output line will pulse for 20-60ms (configurable). The acceptor looks for diameter, thickness, dropping speed, etc to determine if a coin is valid.
k6rtm tweets: “#Adafruit RGB #neopixels with photocell for sensing ambient light levels”
Flora RGB Smart Neo Pixel version 2 – Pack of 4 – What’s a wearable project without LEDs? Our favorite part of the Flora platform is these tiny smart pixels. Designed specifically for wearables, these updated Flora NeoPixels have ultra-cool technology: these ultra-bright LEDs have a constant-current driver cooked right into the LED package! The pixels are chainable – so you only need 1 pin/wire to control as many LEDs as you like. They’re easy to sew, and the chainable design means no crossed threads.