HeatMaster
Our HeatMaster instrument tests the performance of up to six phase-change materials simultaneously. Phase-change materials are the key components of heat batteries. The HeatMaster works using the principle of power compensation in combination with a PID algorithm for temperature control. This means that phase transition upon heating or cooling can be detected in a quantitative fashion as endothermic or exothermic peaks in the recorded data. Full details on the HeatMaster and its applications including extensive thermal cycling are given here.
IceBox
Our IceBox instrument allows investigating the phenomenon of ice nucleation in supercooled water droplets. Within its main unit, an array of 7x7 water droplets is placed. The droplets are then cooled at a defined cooling rate to -30 °C using a Peltier element and the freezing of the droplets is observed with a camera. The humidity inside the IceBox is controlled with the flow of dry argon and measured with a sensor close to the water droplets. The data resulting from the IceBox are fraction-frozen curves that indicate at which temperatures the various droplets frozen. The presence of ice nucleating agents shifts the fraction-frozen curves towards higher temperatures.
Watch a fast-forward movie of a freezing experiment here.
PingPongPID
PID algorithms are everywhere: from thermostats and drones to medical applications and steering ships. Teaching PID control can be a challenge - things get quite mathematical quickly. To make PID control more accessible, we built the PingPongPID instrument. The instrument consists of a long transparent plastic tube with a laser distance sensor at the bottom and a fan from a hairdryer at the top. Most importantly, the tube contains a ping-pong ball.
The PID algorithm operates the fan at just the right voltage so that the ping-pong ball hovers at a setpoint distance. Of course, this will only work if the three PID gain parameters are chosen well. The journey of picking a good set of gain parameters can be demonstrated very nicely with this setup. We are sure that Ziegler and Nichols would be happy with this instrument!
We also designed a GUI (graphical user interface) with Python for running the instrument and recording height data.
You can watch Christoph presenting the PingPongPID in Adafruit’s show-and-tell show here (from minute 13:00).
