Preface

        This project mainly refers to Cai Zi's T20 soldering station controller-release version  project. On this basis, some modifications were made to the hardware. The software was not fully understood, so I re-wrote a similar one with the same functions as the big one. Guy's similar.

        Because there are too many files in a single project, an error will occur when you click Update PCB. It will be fine if you clone the corresponding files into a separate project, including the schematic diagram and PCB of the main control, and the schematic diagram and PCB of the power supply. The board pictures in the project description are slightly different from those in the open source files. The open source files are slightly modified and optimized, and are mainly open source files.

        The price increase of STM32 is so outrageous that it has become a financial product, so I tried several domestic chips, including GD32F103C8/BT6, CKS32F103C8/BT6, HK32F103C8/BT6, and CH32F103C8T6. I have no problem with these chips in short-term testing. I can just use ST-Link to burn the program into them, but it is only for my project. It’s up to you to choose which one to use. In the following text description, I will take the ST one as an example.

1. Project description    

        The main control is STM32F103C8T6, the heating core is a T12 soldering iron, and AD823ARZ is used to amplify the thermocouple potential; the 1.3-inch OLED screen displays various information; the EC11 rotary encoder is for user operation; the EEPROM saves user settings; the external power adapter inputs 24V DC power to supply the T12 soldering iron Header, LM2596S-5.0 and AMS1117-3.3 provide power to each low-voltage module after two-stage voltage reduction ( the original project used 7805 from 24V to 5V. The boss said that the ripple of 7805 is small and the AD conversion reading voltage is more accurate ); the handle is included The vibration switch and thermistor are connected to the main control through a 5-pin aviation plug; the ST-Link interface is reserved for program debugging and downloading.

        Function and operation instructions:

        1. The temperature is adjustable from 200 to 400 ℃, and the temperature rises to tin within 10 seconds , and the error with the set temperature is within 5 ℃;

        2. 1.3-inch OLED digital display, divided into main interface and setting interface, which display various corresponding information respectively;

        3. There are two working modes: normal mode and strong mode. The temperature in strong mode will be 30 °C higher than that of normal mode;

        4. The sleep time and shutdown time are adjustable from 1 to 60 minutes. When the set time is reached, it will automatically sleep or shut down. You can exit the sleep mode by shaking the handle;

        5. It does not heat when it is turned on, and it needs to be pressed briefly to start heating; the settings are automatically read when it is turned on, and modified settings are automatically saved;

        6. Automatically detect whether the soldering iron handle is connected to the main control board. If it is detected that it is not connected, the main interface will give an error message and stop heating. Short press to reconnect and start reheating;

        7. Short press the rotary encoder to return, long press ( press and hold for about 300ms and then release ) to confirm, rotate clockwise to move the cursor upward or increase the value, and rotate counterclockwise to move the cursor downward or decrease the value. .

        Let’s talk about the overall operation process: turn on the switch, power on, the screen will display EDA and my personal logo, and then enter the main interface. The main interface displays the set temperature, current temperature, output power percentage, input voltage and working status. , there are four small icons in the working status, including the handle is not connected, paused, hibernating, and heating; heating will not start at this time, and you need to press and hold the encoder once to start heating; press and hold the encoder on the main interface to enter the setting interface. The setting interface can set the temperature, working mode, sleep time, and shutdown time. These can be set by operating the rotary encoder; after the setting is completed, short press to return to the main interface, and the settings will be automatically saved in the process.

Finished product front side Finished product back side

2. Making tutorials

2.1 Component preparation

        There are two Excel files in the project attachment, which contain detailed component lists. Please do not use the BOM in EDA to place orders. These two files shall prevail. Files ending with LCSC can be uploaded to Lichuang Mall for direct BOM ordering; files ending with TB are components purchased from a certain store, and the corresponding purchase link is also given ( the link is for reference only ). I also wrote in the remarks The specific purchase models are listed. The ones marked in red are necessities. The ones not marked in red are optional. Those are mainly used for connecting the shell and beautifying. Of course, many components can be replaced with similar models. There is no need to use mine. Use whatever you have. ( Note: The EEPROM in the schematic diagram is HT24LC08 because I had this on hand at the time, and the BOM file is AT24C02. In fact, 1Kb is more than enough )

2.2 PCB proofing

      There are a total of 5 PCB files in this project, and the file names say it all. Among them, the main control and power supply must be proofed, and the solder mask color is optional; for the shell, if you choose a 3D printed shell, then proof the front and back of the 3D printed panel. Black solder mask is recommended, which looks good; if you choose an aluminum alloy shell, print on the aluminum alloy shell panel. The detailed opening positions are given in the PCB file of the parameters, and you can just export the file and cut it yourself; the installation method of the two shells is the same. Of course, you can also do without the shell. It’s just a bit unsightly and has no impact. However, the following production instructions take the 3D printed shell as an example.

Below are sample images of four PCB files.

The front and back sides of the power terminal emptying board.                                                                                The front and back sides of the control terminal emptying board.

The upper two are the front and back sides of the 3D proofing panel, and the lower two are the front and back sides.

       I actually got an acrylic sheet and glued it to the screen opening on the front panel. The acrylic size is 33mm × 17.5mm. After customizing it, you can just snap it into the front panel and stick it with glue inside. This is dispensable, it doesn’t matter, the finished pictures were all taken when there was no acrylic board, and I was too lazy to retake it after installing it.

2.3 Shell printing

        At the beginning of the design, I used an aluminum alloy casing. The size of the PCB was also drawn based on the aluminum alloy casing. Then I didn’t have cutting or drilling tools. It took a lot of effort and was finally done, but it was terrible and ugly. So I switched to 3D printing the shell later, which is beautiful. I drew the shell using SW software. It is very simple ( see the picture below ). It is 10cm long, 6cm wide and 6cm high. It is still relatively small. I will also attach attachments to the printed file and just upload it directly to the printing merchant. I used the cheapest consumables for printing, and it came out white. Then I pasted a circle with matte black wallpaper, and paired with the black panel, the overall appearance suddenly improved.

3D printed shell preview

2.4 PCB welding

        Main control board: GX12-5 (5-core aviation plug male), EC11 rotary encoder. These two are not soldered for the time being. All others are soldered. A little tin is applied to the window part. The OLED screen must first use M3*4 dual-pass. The copper pillar is fixed on the main control board, make sure its position is correct before soldering. Then connect the 4 downloaded cables, use ST-Link to download the program ( I will put the program file in the attachment ), observe the OLED display and whether the program is running normally, continue if it is normal, and check if it is not normal. The reason why I downloaded the program here is that I am afraid that it will be welded together with the panel later and cannot be removed, which will cause problems that will be difficult to solve. ---- After the above work is completed, take out the proofed front panel and fix the GX12-5 and EC11 rotary encoders at the corresponding positions. They have nuts-like things that can be fixed. Pay attention to the installation direction. GX12-5 male connector There is a semicircular protrusion inside, which corresponds to the silk screen on the panel ( see the lower left picture in 2.2 ). The encoder should not be inserted incorrectly. Then connect and fix the front panel and main control board with M3*6 double-pass copper posts and M3 screws. If the copper posts are short, you can add a spacer, and finally weld the GX12-5 and encoder. Some pins that are too long can be trimmed appropriately.

Note: If the 5V GND uses an XH2.54 female socket, be sure to match the 5V GND interfaces of the power board and the main control board. Don’t solder the wrong one. If you solder one backward, it will be embarrassing if it burns directly as soon as it is plugged in. ( You can refer to the soldering below. finished picture ).

GX12-5 male connector

        Power supply board: Do not solder the boat-shaped switch first, solder all other parts, put some tin on the window part, and pay attention to the DC power socket. The position must be welded correctly, and it can be aligned with the opening of the panel. After welding other components, take out the proofed rear panel, snap the ship-shaped switch in, pay attention to the direction ( refer to the actual picture in the project description ), and then use M3*11 double-pass copper posts and M3 screws to secure it. If the copper pillar is short, you can add a spacer, and finally weld the ship-shaped switch. Then input 24V DC and measure its output. The normal output is 5V or 24V.

        It looks like this after welding: ( Some of them were put up without welding for taking pictures )

Control end finished product Power end finished product

2.5 Assembly

      Use a multimeter to measure the resistance sum of R9 and R10. You can place the test leads on pins 1 and 2 of the op amp chip to measure, and then adjust R9. For the cutter head, adjust the sum of the two resistors to 280KΩ, and for the small cutter head, adjust the sum to 300KΩ; put the red and black two Cut a silicone wire to an appropriate length, connect one end of the two wires to the 24V interface of the power board, and plug the 2P XH2.54 connecting cable into the 5V interface; buckle the power supply and rear panel into the casing, remember the wires Put it in first and fix it with M3*10 self-tapping screws; put the combined main control and front panel close to the casing, connect the power cord and connecting cable to the main control board, and buckle this thing into the casing. Pay attention The up and down direction, don't face the same direction from front to back, use M3*10 self-tapping screws to fix it. Also fasten the encoder's screw cap. At this point, you have the finished product that looks like the picture in the project description. Then plug in the 24V power adapter, turn on the switch, and enter the main interface after the logo is displayed. It will show that the handle is not plugged in, which does not affect it. At this time, press and hold the rotary encoder to enter the setting interface. Press and hold again to restore the default settings ( this seems to be the case as well). (Official function ), because there is no data in the new EEPROM, you need to restore it first when starting it for the first time.

2.6 Handle production

       Take out the 5-core silicone wire, peel off a little of the black outer sheath on both ends, and peel off a little of the insulation on the 5 inner cores exposed on both sides, and put it aside for later use; take out the female aviation plug, and twist the female aviation plug. Open, divide into two parts ( see picture below ), and set aside.

5-pin female aviation plug

        Take out the pull-out bracket from the handle kit and weld it as shown in the picture below. The color of the font corresponds to the color of the inner core of the silicone wire to be welded.

Plug-in bracket welding reference diagram

        After welding the bracket, unscrew the handle shell from the black thread. Plug the unsoldered end of the 5-core silicone wire out from the inside. Pull the wire to insert the bracket into it. After plugging it, screw the shell in place. Then put the metal part of the 5-core female connector onto the wire first, with the end with the screw facing in. Then weld the 5-core wire as shown in the picture below. The color of the font corresponds to the color of the inner core of the silicone wire to be welded.

Female head welding reference diagram

        Then put the two parts of the female head back together and tighten the screw; then unscrew the silver-white threaded sleeve on the front of the handle, install the T12 soldering iron tip, press it to the bottom, and then screw it back. The handle is now complete.

        Insert the handle into the main control, power on, and press briefly to start heating. The temperature of the new soldering iron tip may not be accurate for the first time. After heating to the set temperature, cut off the power to cool down, and then reheat. In this way, the temperature will be adjusted after two or three times. Right. At this point the entire soldering iron is completed. See the picture below for what it looks like when running, and you can also watch the demo video.

Finished product running chart

The soldering iron tip may burn red during the production process, please be prepared to cut off the power at any time! ! ! Then check the problem.

If you have any questions during the production process, you can comment or send a private message. If you find bugs during use or have optimization suggestions, you can also contact me and I will reply in time.

Coding is not easy. If you find it useful, please give it a thumbs up.