Build Your Own Portable Arduino Soldering Iron

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.

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The A to Z of Building Your Own Keyboard

We’ve featured a number of people who’ve taken the plunge and created their own customized keyboard; at this point it’s safe to say that there’s enough information and source code out there that anyone who’s looking to build their own board won’t have much trouble figuring out how to do so. That being said, it’s nice to have a comprehensive at a process from start to finish. Why sift through forum posts and image galleries looking for crumbs if you don’t have to?

That’s precisely what makes this write-up by [Maarten Tromp] so interesting. He walks the reader through every step of the design and creation of his customized keyboard, from coming up with the rather unique layout to writing the firmware for its AVR microcontroller. It’s a long read, filled with plenty of tips and tricks from a multitude of disciplines.

After looking at other custom boards for inspiration, [Maarten] used OpenSCAD to create a 3D model of his proposed design, and had it printed at Shapeways. His electronics are based around an Atmel ATMega328P using vUSB, and Microchip MCP23017 I/O expanders to connect all the keys. He wrapped it all up by designing a PCB in gEDA PCB and having it sent off for production. As a testament to his attention to detail, everything mated up on the first try.

[Maarten] is happy with the final product, but mentions that in a future revision he would like to add RGB lighting and use a microcontroller that has native USB support. He’d also like to drop the I/O expanders and switch over to Charlieplexing for the key matrix.

From uncommon layouts to diminutive technicolor beauties, it seems there’s no end of custom keyboards in sight. We aren’t complaining.

Don’t Flake on Your Fish—Feed them Automatically

We get it. You love your fish, but they can’t bark or gently nip at your shin flesh to let you know they’re hungry. (And they always kind of look hungry, don’t they?) One day bleeds into the next, and you find yourself wondering if you’ve fed them yet today. Or are you thinking of yesterday? Fish deserve better than that. Why not build them a smart fish feeder?

Domovoy is a completely open-source automatic fish feeder that lets you feed them on a schedule, over Bluetooth, or manually. This simple yet elegant design uses a small stepper motor to drive a 3D-printed auger to deliver the goods. Just open the lid, fill ‘er up with flakes, and program up to four feedings per day through the 3-button and LCD interface. You can even set the dosage, which is measured in complete revolutions of the auger.

It’s built around an ATMega328P, but you’ll have to spin your own board and put the feeder together using his excellent instructions. Hungry to see this feeder in action? Just swim past the break.

Can’t be bothered to feed your fish automatically? Train them to feed themselves.

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Dumb Coffee Grinder Gets Smarter with Time

[Forklift] has a Rancilio Rocky, a prosumer-level coffee grinder that’s been a popular mainstay for the last few decades. It’s a simple machine with a direct-drive motor. Rocky has one job, and it will do that job in one of 55 slightly different ways as long as someone is pushing the grind button. What Rocky doesn’t have is any kind of metering technology. There’s no way to govern the grind length, so repeatable results rely on visual estimates and/or an external clock. Well, there wasn’t until [Forklift] designed a programmable timer from the ground up.

The timer interface is simple—there’s a D-pad of buttons for navigation through the OLED screen, and one button to start the grind. The left and right buttons move through four programmable presets that get stored in the EEPROM of the timer’s bare ATMega328P brain. Grind duration can be adjusted with the up/down buttons.

We like that [Forklift] chose to power it by piggybacking on the 240VAC going to the grinder. The cord through the existing grommet and connects with spade terminals, so there are no permanent modifications to the grinder. Everything about this project is open source, including the files for the 7-segment font [Forklift] designed.

Tea aficionados may argue that creating their potion is the more time sensitive endeavor. We’ve got you covered there. Only question is, one button or two?

A Fully Featured, Fifty Dollar QRP Radio

QRP radio operators try to get maximum range out of minimal power. This term comes from the QRP Q-code, which means “reduce power.” For years, people have built some very low-cost radios for this purpose. Perhaps the best known QRP kit is the Pixie, which can be found for less than $3 on eBay.

The QCX is a new DIY QRP radio kit from QRP Labs. Unlike the Pixie, it has a long list of features. The QCX operates on the 80, 60, 40, 30, 20, or 17 meter bands at up to 5W output power. The display provides tuning information, an S-meter, and a CW decoder. An on-board microswitch functions as a basic Morse key, and external Iambic or straight keys are also supported. An optional GPS can be used as a frequency reference.

The radio is based around the Silicon Labs Si5351A Clock Generator, a PLL chip with three clock outputs ranging from 2.5 kHz to 200 MHz. The system is controlled by an Atmel ATmega328P.

Demand for the kit has been quite high, and unfortunately you’ll have to wait for one. However, you can put down your $49 and learn Morse code while waiting for it to ship. While the project does not appear to be open source, the assembly instructions [PDF warning] provide a full schematic.

ATMega328 3D!

Small OLED displays are inexpensive these days–cheap enough that pairing them with an 8-bit micro is economically feasible. But what can you do with a tiny display and not-entirely-powerful processor? If you are [ttsiodras] you can do a real time 3D rendering. You can see the results in the video below. Not bad for an 8-bit, 8 MHz processor.

The code is a “points-only” renderer. The design drives the OLED over the SPI pins and also outputs frame per second information via the serial port.

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GPS Tracker Gets SMS Upgrade

In May of 2000, then-President Bill Clinton signed a directive that would improve the accuracy of GPS for anyone. Before this switch was flipped, this ability was only available to the military. What followed was an onslaught of GPS devices most noticeable in everyday navigation systems. The large amount of new devices on the market also drove the price down to the point where almost anyone can build their own GPS tracking device from scratch.

The GPS tracker that [Vadim] created makes use not just of GPS, but of the GSM network as well. He uses a Neoway M590 GSM module for access to the cellular network and a NEO-6 GPS module. The cell network is used to send SMS messages that detail the location of the unit itself. Everything is controlled with an ATmega328P, and a lithium-ion battery and some capacitors round out the fully integrated build.

[Vadim] goes into great detail about how all of the modules operate, and has step-by-step instructions on their use that go beyond what one would typically find in a mundane datasheet. The pairing of the GSM and GPS modules seems to go match up well together, much like we have seen GPS and APRS pair for a similar purpose: tracking weather balloons.