original project

https://easyeda.com/wagiminator/z-solderingstation-smd-v2 https://github.com/wagiminator/ATmega-Soldering-Station

1. Overview

T12 Soldering Station Controller Function IntroductionT12 Quick Heating Soldering Station featuring

• Real-time monitoring of soldering iron tip temperature
• Temperature measurement of the tip
• PID temperature control
• Direct or PID control of the heater
• Temperature can be controlled via encoder
• Temperature control via rotary encoder
• Short press the encoder to enter short-term heating mode
• Boost mode by short pressing rotary encoder switch
• Long press the encoder to enter the main menu
• Setup menu by long pressing rotary encoder switch
• Handle vibration detection (requires the handle to contain a vibration sensor)
• Handle movement detection (by checking ball switch)
• Handle connection detection (implemented by determining whether the temperature of the soldering iron tip can be read)
• Iron unconnected detection (by idenfying invalid temperature readings)
• Timer settings - sleep, shutdown time
• Time driven sleep/power off mode if iron is unused (movement detection)
• Can measure main control chip voltage and temperature
• Measurement of input voltage, Vcc and ATmega's internal temperature
• Implement information display on OLED
• Information display on OLED
• Support passive buzzer
• Buzzer
• Allows setting temperature calibration values ​​for different soldering iron tips
• Calibrating and managing different soldering tips
• The settings are saved in EEPROM and will not be lost when power is turned off.
• Storing user settings into the EEPROM
• Allows hot swapping of soldering iron tips and pops up the soldering tip configuration selection menu
• Tip change detection
• Chip overheating and low voltage alarm
• Chip overheating and low voltage alarm
• Better real-time temperature bar and real-time power bar
• Better real-time temperature bar and real-time power bar
• Have transition animation
• Have transition animation
• Built-in screensaver
• Built in screen saver
• Screen flip settings
• Screen flip settings
• Built-in English, Chinese and Japanese language packs
• Built in English, Chinese and Japanese language pack
• Power-on password setting
• Set System Password

Project Video: https://youtu.be/I9ATDxvQ1Bc

Video from John Glavinos (electronics4all): https://youtu.be/4YDcWfOQmz4

Video from LHW-createskyblue (UI-v1.6L): https://b23.tv/LiOe54

2. Versions, Upgrades and Notes

Soldering Station v2.0:

Soldering Station v2.5:

Soldering Station v2.6:

UI Upgrade by createskyblue & lihaoyun6

LHW-createskyblue created an awesome upgrade to the user interface which can be installed optionally. It features:

• Beautify the detail page and increase the power bar
• Menus have ICONS
• Better scrolling animation
• Get rid of the U8g graphics library and use the ArduBoy graphics Library (Lite) to improve the frame rate and reduce memory usage to make graphics possible
• Add flip display Settings to adapt to the habits of different people
• English, Chinese and Japanese language pack
• Screen saver
• System Password
• Better numerical input experience

Video from LHW-createskyblue (UI-v1.6L): https://b23.tv/LiOe54

Notes and Errors

• In the board version 2.5 the diode D1 may overheat. To be on the safe side, the 18V zener diode D4 should be removed and the soldering station should be operated with a maximum of 20V. Alternatively, the diode D1 can be replaced with an SS54 schottky diode and the BJT Q1 with an FMMT619.

3. Power Supply Specification Requirements

Choose a power supply with an output voltage between 16V and 24V which can provide an output current according to the table below. The power supply must be well stabilized. The current and power is determined by the resistance (R = 8 Ohm) of the heater.

4. Temperature Measurement and OpAmp Considerations

A thermocouple (temperature sensor) is located in the T12 soldering tip. It creates a very small voltage depending on the temperature difference between the hot end and the cold junction (about 40 microvolts per degree Celsius). To measure this, the heater must be switched off since both share the same connections. The low voltage is amplified by the OpAmp and measured by the ADC of the microcontroller. The LMV358 is a very cheap and versatile OpAmp, but not the ideal choice for this task because it has a fairly high input offset voltage and is quite noisy. Although the SolderingStation also works with this OpAmp thanks to the software's smoothing and calibration algorithms, I highly recommend spending a little more money in a better one. The OPA2330AIDR or OPA2333AIDR for instance have the same pinout and can also be used with this board. They provide significantly more accurate and stable temperature measurements.

5. Heater High Side Switch with N-Channel MOSFET and Charge Pump

The microcontroller switches the heater on and off via the MOSFET. Since the temperature measurement must be done over the same line and against ground, the MOSFET has to be placed between the supply voltage and the heater (high-side switch). A P-Channel MOSFET is normally used for this configuration. However, N-Channel MOSFETs usually have a lower resistance (RDS (on)), in the case of the IRLR7843 only 3 milliohms. A low resistance means a higher efficiency and a lower heat development of the MOSFET. For an N-channel MOSFET to function as a high-side switch, an additional circuit is required to maintain a positive GATE-TO-SOURCE voltage after the MOSFET is switched on. This is done using a so-called charge pump consisting of a capacitor and a diode.

6. Building Instructions

In addition to the components for the PCB you will need the following:

• 3D-printed case
• Aviator Plug (4- or 5-pin depending on your iron handle)
• DC Power Jack (5.5 * 2.1 mm)
• Rocker Switch (KCD1 15 * 10 mm)
• Some wires
• 4 Self-tapping screws (2.3 * 5 mm)

Make sure that all parts fit nicely into the case. Solder the wires to the connectors and protect them with heat shrinks. Use thick wires (AWG18) for the power connections. Make all connections according to the schematic down below. Solder the wires directly to the corresponding pads on the pcb. To make the soldering station ESD-safe, connect the earth (E) terminal of the aviator plug to a female dupont connector and glue it into the corresponding opening on the case. Now you can connect the soldering station via a male dupont connector to an earth terminal. Upload the firmware and screw the pcb on top of the case.

7. License

This work is licensed under Creative Commons Attribution-ShareAlike 3.0 Unported License. (http://creativecommons.org/licenses/by-sa/3.0/)