I had an interesting idea since I have some LCD displays around now, I have a hakko 936 soldering station, and I looked up the pinout for the connector and found that it uses a thermocouple to sense temperature. I thought it would be cool to add an LCD with the tip temperature, however, thermocouples can only be hooked to one device at a time. Is there a way I could duplicate the signal, or be able to hook it up to an arduino thermocouple board aside from it being connected to the soldering iron board?
thermocouples can only be hooked to one device at a time
Hmm... maybe. Thermocouples put out a small (millivolt) signal that (usually) specialized amplifiers convert to temperature-related higher signals.
But you could Probably pick off the voltage across the thermocouple, amplify it with an Operational Amplifier and get SOME kind of usable signal.
Or you might be able to reverse-engineer what is in the existing circuit and find a better place to pick off a signal.
BUT there may be a major issue with isolation of an Arduino and the existing circuit which may all be running at line voltage.
Not impossible, but challenging...
My HAKKO T12 Tip
T12 have thermocouple in series with the heater with a voltage of around 9mV at 450 degrees celsius.
Might give you some type start.
terryking228:
thermocouples can only be hooked to one device at a time
Hmm... maybe. Thermocouples put out a small (millivolt) signal that (usually) specialized amplifiers convert to temperature-related higher signals.
But you could Probably pick off the voltage across the thermocouple, amplify it with an Operational Amplifier and get SOME kind of usable signal.
Or you might be able to reverse-engineer what is in the existing circuit and find a better place to pick off a signal.
BUT there may be a major issue with isolation of an Arduino and the existing circuit which may all be running at line voltage.
Not impossible, but challenging...
Yeah, I also thought that maybe something after the IC would have an easier way to read it, but I haven't checked the IC numbers or really looked at the circuit to reverse engineer it yet.
Forget about my previous post.
Hakko 936 use RTD instead of thermocouple.
Resistance thermometers, also called resistance temperature detectors or resistive thermal devices (RTDs), are temperature sensors that exploit the predictable change in electrical resistance of some materials with changing temperature. As they are almost invariably made of platinum, they are often called platinum resistance thermometers (PRTs). They are slowly replacing the use of thermocouples in many industrial applications below 600 °C, due to higher accuracy and repeatability.
U2 block diagram
I enclosed 936 diagram and upc1701c tech sheet in Japanese.
Base on upc1701c tech sheet, the pin 4 of U2's voltage related to temperature. Arduino ADC from there.
SOL_936.pdf (47.7 KB)
upc1701c.pdf (253 KB)
Wow, great you have the schematic...
MY Hakko already has a LED display 8)
sonnyyu:
Ahh, wow great info
so basically they use a thermister instead of a thermocouple, that certainly makes it easier.
terryking228:
Wow, great you have the schematic...MY Hakko already has a LED display 8)
Ohh look it mr wee fancy soldering iron
lol nah, this thing is reliable, and the only soldering iron I've had aside from the direct plug in ones, and I figure what the hell why not add something fun into it. I already have blue LED lighting in it XD
oh yeah, that is depending on if it is a 10k thermistor. I'll hook it up later and check.