And all things 'physical' in CPS
When I arrived for the 3AI ‘A’ week and was given the tin box full of ‘build’ goodies, the last thing I expected to see upon opening was a needle and thread. While I was aware that the course would be structured in two parts, a theoretical and a practical element, somehow I had managed to convince myself the build part would consist of writing code and building computing systems. The task, to pass a current through the conductive thread, was a quick introduction into the tactile nature of the course. For the first time I would be creating systems with a form, rather than existing only in cyberspace. When this sewing session was followed up with a trip to the ANU maker space for an induction into machines such as laser cutters, 3D printers and resin printers I knew my abilities would be tested. Never before had I worked with breadboards, resistors, let alone contemplated soldering or using cutting tools. The initial sewing task was a great introduction to circuits as even a beginner like myself could get a light working. While I did look enviously at my new masters colleagues who were creating artistic designs and patterns, I was happy with my limited creation.
This was the approach I continued throughout the semester, where I learnt the basics of each of these skills. My ambition was aligned to the course goals of creating graduates who understand how the technology works rather than becoming experts in it. For example, my goal around electronics was to be able to assemble basic circuitry, and troubleshoot where they go wrong, rather than have a detailed understanding.
My first exposure was in fortnight four where we were asked to create a ‘creature’, a simple machine that consists of a circuit playground express (CPE) capable of translating a sensor input to an actuator's action. I kept my design very simple, which was a fire truck that doubled as a fire alarm. This meant I only needed to wire up the temperature sensor, LED lights and the necessary resistors. The alarm was triggered by the embedded speaker on the CPE. I reused sensors we had explored in the skill session as a way I could learn incrementally and not worry about too many novel elements. One lesson my programming experience has reinforced is the principle of isolation. When trying to debug software to fix an error this can normally be done only by first replicating and isolating the problem. Learning new skills is analogous to this, one at a time and ideally through following along exactly with a tutorial.
My early circuits
My main learning was a practical understanding of the unreliability of types of sensors and actuators. The various temperature sensors I used through the semester returned different readings, even when located next to each other. I ran some mini experiments to compare the output of each sensor- the LM35 Temperature, the onboard temperature sensor in the CPE and an external thermometer (ET) I had. I collected the readings from each of the electronic sensors and printed them out while manually recoding them to the ET. The ET was very stable, maintaining a +- 0.1c range, the CPE sensor fluctuated +- 0.3c, while the LM35 sensor could fluctuate +-3.0c.
The insight that I realised is that I rarely question the sensors used in data collection. I just assume their reliability for quantifiable data like temperature, or sound etc. This taught me to ask more questions on sensors than I would have previously.
Other skills Learned
3D Printing -
Soldering, craft design and lego!