There are times in life when a core thermometer comes in handy (e.g. when brewing beer). But what happens if you don’t have any, but you do have access to an external temperature probe for IKA hotplates with a nice display?
You start hacking, of course. Even in the absence of any documentation, one can easily figure out the wiring of the sensor by having a look at the connector socket on the back of the hotplate.
As you can see, pin 5 is the ground, and pin 4 is some positive voltage, intuitively, the supply voltage for the probe. The only question remaining is the magnitude of this voltage the probe needs, and that can be fortunately read from the probe itself, 8-16 V. So, for making the probe standalone, we only need a 9 V battery, a battery connector and a DIN socket.