Build Your Own Active Load

February 11, 2020 by Lewin Day 29 Comments

When it comes to testing power supplies, it’s useful to have a dummy load to put the gear through its paces. While it’s possible to just use some old heating elements or other big resistors, an active load can provide more control over the process. [Charles Ouweland] found himself in need of just such a piece of gear, and decided to build his own.

Commercial units often pack in a raft of features, operating in different modes from constant resistance, constant power, and constant current. For [Charles]’s needs, just constant current would be fine, and thus the design progressed around this constraint.

The IRFP250 MOSFET specified in the build can dissipate up to 190W, but as it heats up, this is reduced. In this design, cooled by a heatsink and PC fan, [Charles] estimates 120W continous output is a safe limit. It’s combined with an LM358 op-amp and TL431A reference voltage source to act as a current sink, controllable between 0 and 10 amps.

We’re sure that the new hardware makes testing power supplies a cinch for [Charles], and it’s always good to have a strong understanding of the workings of your own test gear. We’ve seen open-source designs in this space, too!

Recreating Fast Oscilloscopes Is A Slow Process

February 10, 2020 by Kristina Panos 20 Comments

If you want to do something you’ve never done before, there are two broadly-defined ways of approaching it: either you learn everything you can about it and try to do it right the first time, or you get in there and get your hands dirty, and work out the details along the way. There’s a lot to be said for living life by the seat of your pants. Just ask anyone who found inspiration in the 11th hour of a deadline, simply because they had no other choice.

Ted Yapo didn’t have a lot of high-speed design knowledge when he set out to build an open-source multi-GHz sampling oscilloscope, but he didn’t let that stop him. Fast forward a year or so, and Ted’s ready to build his third prototype armed with all the hands-on practical knowledge he’s gained from building the first two.

At the 2019 Hackaday Superconference, Ted gave a talk about his journey into the high-stakes world of high-speed design. It’s an inspiring talk, and Ted gives a good look into everything he’s learned in trying to build a sampling ‘scope. We think you’ll appreciate not only Ted’s work, but also the ease with which he explains it all.

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Building A Sound Activated Shop Fan With Arduino

February 10, 2020 by Tom Nardi 12 Comments

Whether you’re using a soldering iron or a table saw, ventilation in the shop is important. Which is why [Atomic Dairy] built a monster air cleaner called the Fanboy that looks like it should be mounted under the wing of an F-15. Realizing a simple switch on the wall wouldn’t do this potent air mover justice, they decided to build a sound activated controller for it.

It’s certainly an elegant idea. The sound created once they kick on their woodworking tools would be difficult to miss by even the most rudimentary of sound-detection hardware. At the most basic level, all they needed was a way for an Arduino to throw a relay once the noise level in the room reached a specific threshold.

Of course it ended up getting a bit more complicated than that, as tends to happen with these kinds of projects. For one, the sound doesn’t directly control the solid state relay used in the fan controller. When the microphone equipped Arduino detects enough noise, it will start a timer that keeps the fan running for two hours. If the tool keeps running, then more time gets added to the clock. This ensures that the air in the room is well circulated even after the cutting and sanding is done.

[Atomic Dairy] also added a few additional features so they could have more direct control over the fan. There’s a button to manually add more time to the clock, and another button to shut it down. There’s even support for a little wireless remote control, so the fan can be operated without having to walk over to the control panel.

We’ve seen some impressive air circulation and dust collection systems over the years, but finding a way to elegantly switch them on and off has always been a problem given the wide array of tools that could be in use at any given time. Sound activation isn’t a perfect solution, but it’s certainly one we’d consider for our own shop.

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Automatic Component Tape Cutter For When Your Electronics Kit Hits The Big Time

February 7, 2020 by Danie Conradie 4 Comments

Even for the simplest of products, production at scale can be big challenge. For example, you might find yourself spending many hours manually counting and cutting strips of component tape to go with the DIY electronics kit your selling on Tindie. [Tom Keddie] found himself in similar position some time ago, and built himself an automated component counter and tape cutter.

[Tom] posted the video of his old machine (see it after the break) after a call for help from another Twitter user who found himself with a lot of component strips to cut. The frame of the machine is made from 20×20 aluminium extrusions and laser cut plexiglass. The tape is pulled off the reel by a stepper motor using a 3D printed sprocket, with the tape held on by Lego wheel and tension spring. A second idler sprocket with tensioner is used to guide the tape through two photo-interrupters that can count holes in opaque tape or the components in clear tape. The cutter itself it an Exacto blade mounted on a wooden block in a guillotine-like arrangement, driven by another stepper motor and a threaded rod as lead screw. Everything is of course controlled by an Arduino. Although not used any more, [Tom] says it worked very well in its day.

The availability of cheap laser cutting, 3D printing and components like aluminium extrusions and stepper motors have really made it possible for anyone to add some automation to production in the home workshop. You won’t be surprised that we’ve seen something like this before, but we’ve also seen similar machines for wiring prep and through-hole resistors. Let us hear your production hacks in the comments, or drop us a tip if you’ve documented it!

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Hoverboard Grows Up, Becomes Magnetic Drill Press

February 4, 2020 by Kristina Panos 11 Comments

If you need to drill metal in tight places, the magnetic drill press, or mag drill is your BFF. The idea here is that a drill press with an electromagnetic base can go anywhere, and even drill horizontally if need be. If you don’t need to use one often, but want one anyway, why not build one out of e-waste?

[DIY KING 00] built this mag drill starting with the motor from a hoverboard. While these three-phase brushless motors have a lot of torque to offer reuse projects like this, they’re not designed to be particularly fast.

He was able to make it about three times faster by cutting the windings apart and reconnecting them in parallel instead of series. He designed a simple PCB to neatly tie all the connections back together and added an electronic speed control (ESC) from an R/C car.

Reluctant to give up the crown, he made his own three-coil electromagnetic base, using a drill to wind magnet wire around temporary chuck-able cores. The coils are then potted in epoxy to keep out dust and drilling debris. Everything runs from two large LiPo batteries, and he can get about 15 minutes of high-torque drilling done before they’re dead. Can you feel the electromagnet pulling you past the break to check out the build and demo video?

Depending on what you’re doing, you might get away with a magnetic vise instead.

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Slice Through Your Problems With A Shukran

February 4, 2020 by Kerry Scharfglass 38 Comments

We’d wager most hackers are familiar with FTDI as the manufacturer of the gold standard USB-UART interfaces. Before parts like the ultra cheap CH340 and CP2102 became common, if you needed to turn a USB cable into a TTL UART device, “an FTDI” (probably an FT232RL) was the way to make that happen. But some of the parts in the FT232* family are capable of much more. Wanting to get at more than a UART, [linker3000] designed the Shukran to unlock the full potential of the FT232H.

The FT232H is interesting because it’s an exceptionally general purpose interface device. Depending on configuration it can turn USB into UART, JTAG, SPI, I2C, and GPIO. Want to prototype the driver for a new sensor? Why bother flashing your Teensy when you can drive it directly from the development machine with an FT232H and the appropriate libraries?

The Shukran is actually a breakout for the “CJMCU FT232H” module available from many fine internet retailers. This board is a breakout that exposes a USB-A connecter on one side and standard 0.1″ headers on the other, with a QFN FT232H and all the passives in the middle. But bare 0.1″ headers (in a square!) require either further breadboarding or a nest of jumper wires to be useful. Enter the Shukran. In this arrangement, the CJMCU board is cheap and handles the SMT components, and the Shukran is easy to assemble and makes it simple to use.

The Shukran gives you LEDs, buttons and switches, and a bunch of pull up resistors (for instance, for I2C) on nicely grouped and labeled headers. But most importantly it provides a fused power supply. Ever killed the USB controller in your computer because you forgot to inline a sacrificial USB hub? This fuse should take care of that risk. If you’re interested in building one of these handy tools, sources and detailed BOM as well as usage instructions are available in the GitHub repo linked at the top.

Review: SanErYiGo SH72 Soldering Iron

January 27, 2020 by Jenny List 34 Comments

When the Miniware TS100 first emerged from China nearly three years ago, it redefined what we could expect from a soldering iron at an affordable price. The lightweight DC-powered temperature controlled iron brought usable power and advanced features in a diminutive package that was easy in the hand, a combination only previously found in much more expensive soldering stations. All this plus its hackability and accessible hardware made it an immediate hit within our community, and many of us have adopted it as our iron of choice.

A surprise has been that it has attracted no serious competitors of a similar type, with the only iron mentioned in the same breath as the TS100 being Miniware’s own USB-C powered TS80. Perhaps that is about to change though, as before Christmas I noticed a new Chinese iron with a very similar outline to the TS100. Has the favourite finally generated a knock-off product? I bought one to find out. Continue reading “Review: SanErYiGo SH72 Soldering Iron” →