By Muuo Wambua,
As promised, Friday the 15th saw a bunch of hardware and software enthusiasts meet-up and hack on the Raspberry Pi, a small, barebones computer developed by The Raspberry Pi Foundation, a UK charity, with the intention of providing low-cost computers and free software to students. The Raspberry Pi can run a number of linux distributions and allows for the attachment of a number of peripherals using the conventional USB, Ethernet and 3.5mm sound ports along with low-level GPIO (General Purpose Input Output) pins.
Kingsley Ndiewo started by introducing the Raspberry Pi, showing the participants how to run it in headless mode via ssh. He also explained how iHub Research and Funtrench had been using the Raspberry Pi to make an automatic door.
Participants were able to see just how easy it was to program the Pi’s GPIO ports using high level programming languages (In this case, Python). Kingsley demo-ed how to turn an LED on and off using python and the nifty RPi.GPIO module. We went on to learn how to accept digital inputsusing pushbuttons and neat ways to filter out unwanted inputs using software.
Next up was Tom Denton (http://blogs.africanmathsinitiative.net/tomd/), who’s involved in number of projects that are aimed at increasing people’s passion for math and tech in Western Kenya. He showed us how to use cron tabs, a useful service that executes scheduled commands in linux. He also showed a copy of Sage (http://www.sagemath.org/) that he’s modified to run on the Raspberry Pi: He hopes to use Sage, in combination with the Pi, to help show children and young adults how to use computation to solve Math problems.
The meet-up was more of an introduction to embedded development on the Raspberry Pi and might have been a little disappointing for the more experienced members. However, it was just a primer for the next few meet-ups, where we plan to work on several hands-on projects that utilize the Pi. Please join iHub_Robotics (https://www.facebook.com/IHubRobotics) on Facebook and send in ideas on possible projects that we can work on.
March 1st Meetup: Once again, we had Robotics enthusiasts gathered at the iHub on the 1st of March to discuss the various projects that they’re working on and hack on interesting projects together.
The session started with William Karumba giving a talk on his Solar Sun tracker. William built his tracking system from scratch, with the purpose of making a mechanism that maximises solar exposure of solar panels, thus increasing their energy throughput.
The most interesting part of his device is that it is made from purely analog components... (Digital systems are a convenient abstraction of analog systems. This results in analog systems being much harder to construct and design, requiring more skill, than comparable digital systems.) which is cool in an age when people find any reason to stick an arduino almost everywhere.
Image from http://xkcd.com/730/ He uses a bunch of op-amp comparators and other discrete components to come up with a [deceptively] simple circuit that orients a panel towards the direction the most light is coming from. He served as a reminder that we shouldn’t be afraid to get our hands dirty and use more complicated analog electronic circuits in our projects.
Next, we moved on to the mini project of the day. As a primer: In the next couple weeks, the robotics group will be working on mini-projects to encourage member’s creativity and build electronics and programming skills. The projects that we’ll be working on are:
- Pi Synthesizer:
Objective: Construct a circuit that will allow one to play and mix different sounds using push buttons and the raspberry pi.
- Handshake Gorilla:
Objective: Use art and the raspberry pi/arduino to make a gorilla that shakes your hand when you touch its hand.
This project is based on a workshop conducted by Jens Dyvik (http://www.dyvikdesign.com/site/research/fablab/handshake-gorilla-workshop-at-fablab-kamakura.html)
- Polling Station:
Objective: Use the raspberry pi to make an electronic polling station for the presidential elections
On the 1st we decided to start work on the Polling Station. We got lots of good ideas for its design from the attendees and eventually we came up with a basic design for the polling station:
The final design consisted of push buttons for [a hypothetical] four elective positions; A green LED to indicate that one can now make their vote and a green LED to indicate that one should wait a little while before voting.
Here’s a more clear schematic of the simple circuit we came up with:
After setting up the circuit, the task of programming the Raspberry Pi to tally the votes and control the voting process remained. We decided to do this in Python using the RPi.GPIO module. Unfortunately, we weren’t able finish up the coding bit (due to time constraints), but we’ll be able to pick up where we left off when we meet this Friday(15th March). See you there at 4pm!
You can also join iHub_Robotics (https://www.facebook.com/IHubRobotics) on Facebook and send in ideas on possible projects that we can work on.