A Tale of Three Soldering Iron Controllers

[ZL2PD] needed to replace an old Weller soldering station and decided not to go with one of the cheap soldering stations you can find all over the Internet. He has a long story about why he had to design his own controller, but you never have to explain that to us. He kept detailed notes of his journey and in the end, he built three different controllers before settling on one.

He started with a Hakko hand piece that uses a thermistor for temperature measurements. The first iteration of the controller had analog controls. He wasn’t happy with the number of parts in the design and the simple LED display. That led him to replace the controller with an ATTiny CPU and a use a serial LCD.

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Hacking Amazing Soldering Features into the Already Great Weller WMRP

Weller, the German soldering tools manufacturer, has a nice range of micro soldering irons (pencils) designated as the WMRP series. These are 12V, 40 W or 55W units with a 3 second heat up time, and allow quick tip exchange without needing any tools. [FlyGlas] built a neat soldering station / controller for the WMRP series based around an ATMega microcontroller running Arduino.

It’s packed with most of the features you see in a professional rig.

  • low offset op amp for soldering tip temperature measurement with type c thermocouple
  • cold junction compensation using the PTC (KTY82-210) included in the WMRP soldering pencil
  • input voltage measurement
  • soldering pencil current measurement
  • recognizing if the soldering pencil rests in the stand (–> standby)
  • 3 buttons to save and recall temperature values
  • rotary encoder to set soldering temperature
  • illuminated 16×2 character LCD module
  • USB for debugging and firmware update
  • 4mm safety socket for +12V power input and a protective earth socket for connection to ESD protection

WMRP_controller_02A PWM signal from the microcontroller controls the load current using a MOSFET. Load current is measured using a Hall Effect-Based Linear Current Sensor – ACS712. The corresponding linear output voltage is buffered and slightly amplified using AD8552 zero drift, single supply, RRIO Dual Op Amp before being sent to the microcontroller ADC input. To ensure ADC measurements are accurate and stable, a low noise precision voltage reference – ADR392 is used. Another precision resistive voltage divider allows input voltage measurement. The supply input has over-current and reverse voltage protection. A set of buttons and a rotary encoder are connected to the microcontroller to allow settings and adjustments. An analog section measures the thermocouple voltage from the soldering pencil as well as the stand-by switch status. The handle has an embedded reed switch that is activated by a magnet in the support stand which puts it into stand-by mode. Another analog section performs cold junction compensation using the PTC sensor within the soldering pencil.

The Git repo contains the initial Arduino code which is still a work in progress. While the hardware source files are not available, the repo does have the pdf’s, gerbers and BOM list, if you want to take a shot at building it. Check a demo video after the break. Thanks [Martin] for sending in the tip.

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Workbench With Built-In Solder Fume Extractor


There’s nothing quite like getting an eye full of solder fumes, but when it comes to solder fume extraction, the most common solution take up a whole lot of work area. Here’s a very clever solder fume extractor that doesn’t get in the way, and can be perfectly positioned over the acrid brimstone of a soldering station.

The build consists of a cheap bathroom vent fan built into the back of the workbench feeding into a long PVC pipe that blows the exhaust to the floor a few feet away. The fan is controlled by a simple wall switch, but the intake is where this build really shines. It’s a series of hard, flexible plastic segments that allow the intake to be precisely oriented above the work piece, or wherever it’s most convienent to suck solder fumes from.

This solder fume extractor is just a part of a really amazing electronics workbench. A lot of thought went into this workspace, from threaded inserts in the work surface to mount a panavise to an amazingly thoughtful equipment rack for computers, monitors, and other assorted heavy equipment.

via Hacked Gadgets

Solder station hack adds temperature control

Take that cheap fire stick you call a soldering iron and turn it into a real tool. [Giorgos Lazaridis] turned his 30 watt soldering iron into a temperature controlled soldering station by adding a thermistor just above the tip to monitor how hot things are getting. A MAX6675 takes care of the thermocouple and shoots a digital temperature value off to the PIC 16F88 which controls the unit by taking user input from a potentiometer and displaying the settings on an HD44780 character display. His use of a dissected ‘wall wort’ inside of the ATX power supply carcass used as the case for the station is a clever hack. See it melt some metal in the clip after the break.

This makes a nice upgrade to our solder station guide, which had a temperature controlled iron but lacked the sensor and automation seen here. Continue reading “Solder station hack adds temperature control”