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Messages - diogoc

6
Project logs / Re: My HAKKO classic and T12/T15 soldering controller
It depends of the reference voltage that you use for the ADC, but if you use the 3.3V supply the gain should be around that.

The best op-amp I think is the AD620, but you can use the OP07.
You should use an op-amp with low offset voltage and temperature drift.
7
Project logs / Re: My HAKKO classic and T12/T15 soldering controller
[quote author="Ryan111"]1- you said that you used a 24V dc laptop power supply but how much current? Is 3A enough?(70/24~3A)
[/quote]
I used a 90W adapter. The T12 tips are 70W, but it is better to give some margin.

[quote author="Ryan111"]2- My MCU is a 3.3v (unlike your MCU that is a 5v) then I have a problem. there is no problem for transistors (I can bias them) but I don't know how and what should I chenge for Op-Amps?[/quote]
You can use 3.3V to drive the transistors without problem, you don't have to change anything or at least reduce a little the R11.
In the op-amp you only have to adjust de gain (P1) to ensure that the output voltage is always below than 3.3V
9
Project logs / Re: My HAKKO classic and T12/T15 soldering controller
I was just kidding. I dont want a Metcal controller.
It is a different functional concept of most soldering drivers. Uses an ingenious way for heating, it's true.
My company has one of these Metcal stations and the few times I used it I was not impressed. It is not so quick to heat up, it have a big and heavy controller, sometimes when changing the tip it is not detected, and offcourse the disadvantage of not being able to choose the temperature.
Probably the temperature stabilization is better, I don't know.
12
Project logs / Re: My HAKKO classic and T12/T15 soldering controller
The 15V zener makes sense.

Z1 and R7 are necessary because I'm using ICD2 to program the pic.
ICD2 minimum vpp voltage is 12V and maximum allowed vpp in this pic is 9V.

I used the MCP6V07 because I already had that component, and it was not worth buying another.
Initially the second opamp was to be used in the ambient temperature sensor, but it was not necessary.
13
Project logs / Re: My HAKKO classic and T12/T15 soldering controller
[quote author="randomone"]Looks good, when do we get to see the dirty details ? Schematic, code etc.[/quote]

I added some photos of the internal of the soldering station.
I have edited the post to include the schematics.
Later I will upload the source files.
14
Project logs / Re: My HAKKO classic and T12/T15 soldering controller
I finally finished my Hakko T12 soldering controller.
Thanks to sparkybg and arhi for all help and sugestions.

Some features of the controller:
- 3310 graphic display
- rotary encoder for easy and fast temperature selection
- sleep mode when the iron is in the stand
- turn off when a long time in sleep mode
- audible indications
- intuitive menu navegation
- percentage visualization of output power
- powered by a compact and lightweight 24V dc laptop power supply
- ambient temperature sensor for a better cold junction compensation
- lcd backlight control
- alarm for very high temperature, turning off immediately the heater
- indication of tip removed to allow hot swapping the tips
- bootloader for easy firmware upgrade via integrated usb port
- usb port and c# software to monitoring all parameters and help to adjust the pid parameters

The controller still need a little adjust in the PID parameters but for me it is almost perfect.
Here are some photos of my soldering station. The case was an old ups :)
https://plus.google.com/photos/10961235 ... 8092650129

I know the pcb is not very pretty. I could have done in smd but I wanted a pcb that was easy for me to do at home and to reuse the components that I already had.