A beautiful open source T12 soldering station

An appearance modification based on ATmega SolderingStation SMD v2 - EasyEDA , making it more friendly to common 88*38 shells

First of all, this all stems from my need for a T12 soldering iron, so this project almost started from scratch. Here I will tell you about the production process and precautions of this project.

First of all, I have prepared a time schedule for making this project for everyone.

First, let me introduce this project. This project was originally submitted on EasyEDA by a big guy named Wagminator.

There are two versions of the program, one is his own original, and the other is the UI modified version of createskyblue. The scalability of these two programs is already relatively small, because Flash takes up a lot of space and there is not much room for modification.

Including slight modifications to the pin definitions on the hardware, an NTC resistor inside the handle is connected to ADC2. Interested friends can follow along and modify the program content.

hardware design

What deserves more attention is the switch of this hardware

This project uses an m328 chip as the main control, with an external OLED screen and rotary encoder. The hardware supports handle vibration sleep. The hardware also has temperature feedback from the NTC inside the handle. The soldering iron tip is grounded to prevent the switching power supply from being hot or cold. Problems caused by poor isolation performance

The hardware switch uses an N-CH MOS charge pump bootstrap boosted high-arm switch (N-Channel to maintain a relatively small Rds(on), and at the same time, it is more convenient to measure the voltage of the thermocouple during feedback)

 

The structure of the T12 heating head can be seen as a thermocouple (it is rumored that its thermal electromotive force is half of TYPE-K, so it is similar to TYPE-N) connected in series with a heating core. The cold end of the thermocouple is grounded and connected in series with the 8Ω heating core. Ignoring the influence of the resistance of the heating core, we can measure the potential at both ends of the thermocouple and then derive the current temperature. Since its cold end is grounded, its back-end op amp

The ground reference is the same, so it is easier to do amplified detection without having to use a differential input structure.

 

The shell looks like this

This is a very common (88*38*110) shell used in T12 soldering stations. Note that the shell mentioned here only refers to the upper and lower shells and does not include the front and rear panels.

The rear panel is a typical slot, which can be put into a (exposed buckle part ~50*30) female socket with fuse

There are many things worth noting about the front panel. I highly recommend that you purchase a T12 case to verify the shape data before building a board. I marked the corresponding data in the two PCB files so that they can be compared more easily.

Or you can buy the same case according to my purchase address ( here ). This is not an advertisement! It just feels quite affordable when you purchase it yourself (you can contact the store first and buy a case + front and rear panels. They also provide this case. The designed power supply, but omits a lot of things, such as some Y capacitors and common mode inductors.)

 

Ignore the two very abrupt power supply lines in the upper right corner. The old version did not provide enough solder pads, and the current project file has been repaired.

 

Purchase heating head related content

The remaining content is to purchase content related to the heating head, including (the link attached below is my own purchase plan, for reference only)

• T12 heating core
• 5pin Aviator male and female connector GX12
• 5-core silicone cable
• Controller bracket and handle (the bracket is the PCB structure in the handle )
• Vibration switch on the handle bracket
• NTC on handle bracket (optional)

Note that when installing the handle vibration switch, the pins on the gold side should face upward, otherwise the sensitivity will be extremely poor.

 

Here are the steps to assemble the handle-front panel:

1. The silicone wire is passed through the handle, and then the color is assigned by itself and soldered to the bracket PCB.
2. Weld the NTC and vibration switch (pay attention to the direction), then return the bracket to its position and tighten the nut blocking the front.
3. Insert the heating core, then the metal sleeve for the heating core, and tighten the nut. The handle is assembled
4. Disconnect the other end of the silicone wire and separate the male and female ends of the aviation plug.
5. Make sure the screen and encoder on the back of the PCB are welded (burn the program in advance for testing)
6. The male header passes through the front panel and is soldered to the rear PCB. Note that this process is difficult to reverse, so please make sure that the previous preparations have been done.
7. Remove the screws from the female head, weld the silicone wire according to the pinout, pay attention to sorting out the mirroring problem, and then replace the nut.

 

How to connect the slots on the rear panel

 

The above is the general installation process

For program location, please visit Wagminator's EasyEDA project