Thursday, January 26, 2012


Happy new years! 2012 is off to a quick start. Some projects have been finished just in time for the Christmas break, others seem to drag on indefinitely.

I was asked to make a statistics readout that updates important facts in real time. After looking around online I ended up picking the wrong display for cost reasons. I went with a commercial LED sign ( intended for use at a restaurant or shop that is to be programmed once and forgotten. While it had the serial port I was looking for, the manufacturer never intended it to receive live data. I ended up using Advanced Serial Port Monitor to figure out the programming protocol used when loading messages with the included PC software. After making a table of message components I set to getting an Arduino talking to the displays. Luckily they are addressable so I had a common serial bus sharing the hardware UART. After much fiddling it was done; the Arduino loads in 90 'messages' at a time which the display slowly rotates through until it needs another set of numbers. Not elegant but it worked.

Also in the new gallery; "Every 10 Seconds" an interactive exhibit about just how much gets consumed every ten seconds. Guests are asked to hold the button down for as close to ten seconds as then can. A statistic is then multiplied by their time and displayed ie; "Your time was 9.845 seconds, in that time North America consumed 78439 barrels of oil." This exhibit was created with a small form factor PC connected to an Arduino. The graphics were created using Adobe Illustrator and loaded in a PC application written in Processing. The case is rolled aluminum with supports welded inside. It was powder coated by a local shop an assembled on site. The top plaque is MDF with a vinyl graphic applied, it turned out all right but next time I would not have the printers be the ones to apply the graphic, the curved edges did not turn out so well.

My next favorite project at work will be the recommissioning of a cloud chamber. This thing has sat in storage for a decade and is exactly the sort of device I love working on. Combining high voltage, compressors, control loops, German and alcohol; the thing produces a fog of ethanol in which subatomic particles can be visualized.
It first came to the center in the early 90's from a shop in Germany specializing in scientific apparatus. Basically, an 80 x 80 cm plate of copper is chilled to - 20°C and alcohol is vaporized onto it forming a super saturated 'cloud'. Background radiation passing through this cloud causes ionized trails to become visible to guests staring into it.

To left; the electronics panel. Below; the compressor and condenser coils used to chill the plate.

My current personal project is an automotive control system. The focus is on getting a useful lambda sensor reading but extra I/O is provided for connection to other sensors and actuators. The device below is the results of my crappy welding job; a tailpipe O2 sensor mount. This will let me test out the sensor interface board without cutting into the existing exhaust system of my car.