Planet Arduino

A few months ago we brought word that [Electronoobs] was working on his own open source alternative to pocket-sized temperature controlled soldering irons like the TS100. Powered by the ATMega328p microcontroller and utilizing a 3D printed enclosure, his version could be built for as little as $15 USD depending on where you sourced your parts from. But by his own admission, the design was held back by the quality of the $5 replacement soldering iron tips he designed it around. As the saying goes, you get what you pay for.

But [Electronoobs] is back with the second version of his DIY portable soldering iron, and this time it’s using the vastly superior HAKKO T12 style tip. As this tip has the thermocouple and heating element in series it involved a fairly extensive redesign of the entire project, but in the end it’s worth it. After all, a soldering iron is really only as good as its tip to begin with.

This version of the iron deletes the MAX6675 used in V1, and replaces it with a LM358 operational amplifier to read the thermocouple in the T12 tip. [Electronoobs] then used an external thermocouple to compare the LM358’s output to the actual temperature at the tip. With this data he created a function which will return tip temperature from the analog voltage.

While the physical and electrical elements of the tip changed substantially, a lot of the design is still the same from the first version. In addition to the ATMega328p microcontroller, version 2.0 of the iron still uses the same 128×32 I2C OLED display, MOSFET, and 5V buck converter from the original iron. That said, [Electronoobs] is already considering a third revision that will make the iron even smaller by replacing the MOSFET and buck converter. It might be best to consider this an intermediate step before the DIY iron takes on its final form, which we’re very interested in seeing.

The first version of the DIY Arduino soldering iron garnered quite a bit of attention, so it seems there’s a decent number of you out there who aren’t content with just plunking down the cash for the TS100.

[Thanks to BaldPower for the tip.]

At this point you’ve almost certainly seen one of these low-cost portable soldering irons, perhaps best exemplified by the TS100, a pocket-sized temperature controlled iron that can be had for as little as $50 USD from the usual overseas suppliers. Whether or not you’re personally a fan of the portable irons compared to a soldering station, the fact remains that these small irons are becoming increasingly popular with hackers and makers that are operating on a budget or in a small workspace.

Believing that imitation is the most sincere form of flattery, [Electronoobs] has come up with a DIY portable soldering iron that the adventurous hacker can build themselves. Powered by an ATMega328p pulled out of an Arduino Nano, if offers the same software customization options of the TS100 but at a considerably lower price. Depending on where you source your components, you should be able to build one of these irons for as little as $15.

The iron features a custom PCB and MAX6675 thermocouple amplifier to measure tip temperature. A basic user interface is provided by two tactile buttons on the PCB as well as an 128×32 I2C OLED display. In a future version, [Electronoobs] says he will look into adding some kind of sensor to detect when the iron is actually being used and put it to sleep when inactive.

The tip is sourced from a cheap soldering station replacement iron, and according to [Electronoobs], is probably the weakest element of the entire build. He’s looking into using replacement TS100 tips, but says he’ll need to redesign his electronics to make it compatible. The case is a simple 3D printed affair, which looks solid enough, but seems likely to be streamlined in later versions.

We’ve seen a number of attempts at DIY soldering irons over the years, but we have to say, this one is probably the most professional we’ve ever seen. It will be interesting to see how future revisions improve on this already strong initial showing.