PS One – a Lab Bench Power Supply for the Arduino and Phidgets platform
I used to work as an ICT Executive at Clementi Town Secondary School and among the many responsibilities I had was to introduce innovation for the school. One of the innovation ideas I contributed was to start a Special Interest Group for the Arduino Microcontroller.
Since I wanted to do more, the first project of a series of projects I wanted for the school was to first build a Laboratory Power Supply in order to be able to design interface circuits for the Arduino with 5 volts, 12 volts and 24 volts DC output.
I wanted my design to have a social dimension whereby, I wanted the students from the D&T Program to be able to break away from the rut and apathy and empower them to be able to build something cool, something relevant, something useful, from something we can recycle and repurpose.
Then it hit me to build a Lab Bench Power supply out of old discarded Computer ATX Power Supplies. It had to be cool and be a form of electronic art as well as something robust, reliable and short circuit proof.
To be cool and appealing to the student friends of mine, I built it housed on clear acrylic plastic. I designed my very own trigger circuit from an SR Latch Integrated Circuit with easily available components from Sim Lim Tower.
I solicited the help of our D&T Head of Department to draft Solidworks CAD drawings of the enclosure and use a laser cut machine.
The casing turned out awesome and all I needed to do was wire up the thing and fire it up and test it.
Part of the challenge was to also make it nostalgic so I opted to use an Analog Amp Meter. I couldn’t find a 0 to 25 ampere DC Amp Meter so I chose a 0 to 30 amp instead and my decision was correct since at short circuit conditions prior to the power supply going into protection mode, the current would easily go past 25 amperes.
The choice of wiring materials also played a part to make it cool and make this a form of electronic art. I chose the power cables used for wiring Automotive Sound systems and it turned out great as well as overkill for the amperage that will pass thru the wires especially at short distance runs.
The hard part was choosing heavy duty binding posts and terminal blocks that won’t cost a bomb. I also wanted this to be sort of a general purpose design so I incorporated a cigarette lighter socket which can at least carry more than 20 amperes without melting.
It took me a total of 5 weeks to complete but it was a very rewarding project upon completion worthy of being displayed and showcased.