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Author: Subject: DIY temperature probe for hotplate, help!
Download
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[*] posted on 6-12-2020 at 19:54


I haven't bothered to read everyone else's posts but I'm going to suggest forgetting making a "proper" interface.

Instead, get yourself a solid state relay, hook it up inside the hotplate so it can disconnect the hotplate when power is applied, and then have an external connection which goes to a digital thermostat. On ebay and Aliexpress and those sorts of places you can pick up a thermostat that takes K-type thermocouples for less than US$5 with shipping. The thermostat can turn the hotplate on and off for you.

Doing it the proper way might look neater, but you'll spend loads of time and money figuring it out.
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[*] posted on 6-12-2020 at 20:03


Quote: Originally posted by Download  
I haven't bothered to read everyone else's posts but I'm going to suggest forgetting making a "proper" interface.

Instead, get yourself a solid state relay, hook it up inside the hotplate so it can disconnect the hotplate when power is applied, and then have an external connection which goes to a digital thermostat. On ebay and Aliexpress and those sorts of places you can pick up a thermostat that takes K-type thermocouples for less than US$5 with shipping. The thermostat can turn the hotplate on and off for you.

Doing it the proper way might look neater, but you'll spend loads of time and money figuring it out.


If you do this you will have to break the circuit for the heating element, otherwise you'll lose stirring as it switches the PID controlled relay on and off.
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[*] posted on 7-12-2020 at 14:23


Quote: Originally posted by p4rtridg3  
After testing some LM35s I got online, I can confirm that it is in fact the cold junction compensator for the probe. Now all I need to do is wire it up.


Its kind of surprising just how much reverse engineering can be done from a photo of a PCB.

Always makes me laugh inside when I visit a tech company and have to leave my phone at reception. When a glance inside their product will tell me most of what I need to know...




Helicopter: "helico" -> spiral, "pter" -> with wings
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