Hi all,
So I have this little project where I'd like to "upgrade" my soldering iron.
It's a VTSS20 (
http://www.velleman.eu/downloads/1/vtss20vtss30gbnlfresd.pdf) soldering iron from Velleman.
They say you can set the temperature from 150°C to 420°C.
Being a bit bored a couple days ago, I opened the case, measured here and there, and found the temperature sensor signal.
I couldn't find any datasheet on what type of temperature sensor they use and what the output voltage is per °C, so I just turned the pot to it's max value and measured the voltage of the temperature sensor. The temperature sensor signal goes through a x60 amplifier and I measured 1.36V for (I suppose) 420°C.
I'm using a PIC16F877A to write on a winstar 2x16 OLED display. (I was testing my display library on the 16F877A before trying to use it as a temperature meter, I'm probably changing that to a 16F88)
I added a little opamp to amplifie the temperature sensor voltage, because 0V-1.36V with a 5V ref at the ADC isn't that great. Now I have like 0V-4.24V
.
My program just measures the voltage:
voltage = ADC * (5.0 / 1024.0);
And converts that to a temperature:
temperature = voltage * (420.0 / 4.24);
Anyways, the thing I wanted to ask you guys is if anyone knew what the V/°C is on this soldering iron.
Btw, the soldering iron is a 24V 48W model SL-1 or SL-I.
I would like to know the exact V/°C so I can have a precise temperature. I don't have the tool to measure the temperature of the soldering iron either to verify if the soldering iron is 420°C when the temperature control is set at maximum.
Here are some pics :
EDIT:
I want to "upgrade" it so I can set a temperature and have both the actual temperature and set temperature displayed on the OLED.
If you have other ideas, let me hear them.