Another Neat General Purpose Soldering Iron Driver

January 31, 2022 by Dave Rowntree 26 Comments

Over on Hackaday.io, user [Tomasz Jastrzebski] has designed a tidy-looking custom controller for driving temperature-controlled soldering irons. The design is intended to be general purpose, capable of operating with irons rated for different voltages and probe type, be they thermocouple- or thermistor-based. Rather than integrating a power supply, this is handled by an external unit, giving the possibility of feeding this from a variety of sources that are not necessarily tied to the grid.

Hardware-wise, we’ve got the ubiquitous STM32 microcontroller in charge of the show, with a nice front end based on the INA823 instrumentation amplifier, referenced to a REF2030 precision voltage source. The input stage is configured as a versatile Wheatstone bridge input circuit, giving plenty of scope for tweaking.

There are a few extra features in the design that aren’t necessarily needed for a soldering iron driver, such as RTC support, complete with supercapacitor backup, but then this doesn’t have to drive a soldering iron, it could drive any DC heater with temperature feedback. With a change in firmware, this could serve other tasks. One potential feature that springs to mind — have the unit automatically power down at a certain time of day in case it was left on accidentally.

The schematic has a lot of relevant detail — in that many parts have a good list of alternatives, presumably because of the semiconductor shortages — which is a good habit to get into if you ask us. Many of us involved with manufacturing have been doing this for years, as it makes sense to give the assembly house the extra options, but this really is basically mandatory practice now.

Firmware for the STM32G0 series microcontroller is based on the STM32 HAL, keeping it simple, with a Visual Studio Code project provided for your convenience. All hardware (KiCAD) and firmware can be found on the project GitHub.

We’ve seen a few projects like this over the years, like this Really Universal Soldering Controller, a custom controller for JBC irons, and this great portable Arduino-based unit.

Blast Chips With This BBQ Lighter Fault Injection Tool

January 29, 2022 by Dan Maloney 16 Comments

Looking to get into fault injection for your reverse engineering projects, but don’t have the cash to lay out for the necessary hardware? Fear not, for the tools to glitch a chip may be as close as the nearest barbecue grill.

If you don’t know what chip glitching is, perhaps a primer is in order. Glitching, more formally known as electromagnetic fault injection (EMFI), or simply fault injection, is a technique that uses a pulse of electromagnetic energy to induce a fault in a running microcontroller or microprocessor. If the pulse occurs at just the right time, it may force the processor to skip an instruction, leaving the system in a potentially exploitable state.

EMFI tools are commercially available — we even recently featured a kit to build your own — but [rqu]’s homebrew version is decidedly simpler and cheaper than just about anything else. It consists of a piezoelectric gas grill igniter, a little bit of enameled magnet wire, and half of a small toroidal ferrite core. The core fragment gets a few turns of wire, which then gets soldered to the terminals on the igniter. Pressing the button generates a high-voltage pulse, which gets turned into an electromagnetic pulse by the coil. There’s a video of the tool in use in the Twitter thread, showing it easily glitching a PIC running a simple loop program.

To be sure, a tool as simple as this won’t do the trick in every situation, but it’s a cheap way to start exploring the potential of fault injection.

Thanks to [Jonas] for the tip.

3D Printed Jig Makes Custom Springs A Snap

January 28, 2022 by Tom Nardi 13 Comments

We’ve often heard it said that springs come in in all shapes and sizes…except for the one you need. In light of this, the hardware hacker would do well to keep the tools and knowledge required to make a custom spring close at hand when building something that moves. Luckily, all it really take is some stiff metal wire, a rod, and patience.

Unless you’ve got a 3D printer, that is. In which case, we’d suggest you print out this very clever “Spring Factory” designed by [Vincent Baillet]. The simple tool, consisting of just two parts, makes it easier and faster to make consistent DIY springs when compared to traditional methods. Rather than trying to eyeball the spacing of the coil as you wind the wire around the mandrel, this design does it for you.

As seen in the video, springs made with this tool look very professional. Not only does the threaded mandrel keep the spacing between coils even, it also makes sure all the springs you produce are identical. This can be especially important with projects that need to use multiple matching springs. [Vincent] says his handy tool works with piano wire from 0.8 to 1.2 mm, and slightly thicker if plain steel.

Of course, the obvious flaw in a tool like this is that it can only be used to make springs of a specific diameter. Changing the length is easy enough, just use more or less wire. But to make a thinner or thicker spring, you’d need a different size of mandrel. It seems that [Vincent] has only released the gadget in this approximately 9 mm diameter so far, but here’s hoping a few more sizes get added to the mix before too long.

Looking for something a bit more advanced? This Arduino-powered wire bender is capable of making some very impressive custom springs, among other things.

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Laser Z-Axis Table Comes Into Focus

January 25, 2022 by Bryan Cockfield 2 Comments

Laser cutters and 3D printers are game-changing tools to have in the workshop. They make rapid prototyping or repairs to existing projects a breeze as they can churn out new parts with high precision in a very short amount of time. The flip side of that, though, is that they can require quite a bit of maintenance. [Timo] has learned this lesson over his years-long saga owning a laser cutter, although he has attempted to remedy most of the problems on his own, this time by building a Z-axis table on his own rather than buying an expensive commercial offering.

The Z-axis table is especially important for lasers because a precise distance from the lens to the workpiece is needed to ensure the beams’s focal point is correctly positioned. Ensuring this distance is uniform over the entire bed can be a project all on its own. For this build, [Timo] started by building a simple table that allowed all four corners to be adjusted, but quickly moved on to a belt-driven solution that uses a stepper motor in order to adjust the entire workspace. The key to the build was learning about his specific laser’s focal distance which he found experimentally by cutting a slot in an angled piece of wood and measuring the height where the cut was the cleanest.

After everything was built, [Timo] ended up with a Z-axis table that is easily adjustable to the specific height required by his laser. Having a laser cutter on hand to bootstrap this project definitely helped, and it also seems to be an improvement on any of the commercial offerings as well. This also illustrates a specific example of how a laser cutter may be among the best tools for prototyping parts and building one-off or custom tools of any sort.

Tiny Homemade Injection Molder

January 24, 2022 by Matthew Carlson 17 Comments

With 3D printing continually gaining ground, some hackers might not see the need for traditional injection molding. After all, you can tweak the code or the model and print dozens of different iterations with fairly minimal lead time. Things get trickier when you need to print hundreds or thousands of the same thing and that ten-hour print time adds up quickly. [Actionbox] built a tiny injection molder they dubbed INJEKTO to speed up their manufacturing.

The design was optimized to be accessible as it is held together with brackets and cheap aluminum flat stock. The hardest part to source is the heating chamber, as it is a piece of turned aluminum. A PID controller keeps the temperature relatively stable and heats the plastic pellets you can dump in the top. Next, you’ll need an external air compressor to power the dual 2″ pneumatic pistons. The pistons push the plastic out of the spring-loaded extruder nozzle. [Actionbox] is already planning on a second version with 4″ pistons that provide significantly more force to extrude larger amounts of plastic as the current version tops out at about 27 grams.

Injection molding still needs a heavy-duty mold to inject into, which can be hard to machine. So until we can 3D print an injection mold, this multi-head 3D printer is something in between a 3D printer and an injection molder, as it can print a dozen of the same thing, speeding up that print time.

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Hacked DSP5005 unit showing amp-hours screen

Another DPS5005 Alternative Firmware

January 22, 2022 by Dave Rowntree 9 Comments

These cheap Chinese-built programmable power supplies are nothing new, we’ve been using them for years. They’re not particularly good power supplies, since current feedback is in software, but for some tasks they’re a great fit and you can’t argue with the price. Alternative firmware projects have also been a thing for a while too, but none we’ve seen have been quite as capable and polished as this latest DPS firmware project by [Profi-max.] We’ve not come across the source code yet, but at least the binary image is freely downloadable.

The firmware has some interesting features, such as programmable pre-sets intended for battery charging applications. In fact, there is a dedicated battery charge mode screen. We want to warn, however, that charging lithium ion batteries with this might not be at all wise, not in the least because of a lack of protection hardware in place. It would be very easy to destroy the unit or overheat a battery this way! However, if you must do this, there are a few features to help you out, such as a handy ‘counters’ screen showing approximate charge delivered.

Remote programmability is, as usual, via the easily hacked in serial port, with firmware support for Bluetooth serial modules if wired USB serial doesn’t suit. For those who like to mount things differently, the screen can be rotated by holding a key on power-up, or if you hook up a MPU6050 accelerometer/gyro module it will even do it automatically!

To update a stock DPS unit, the only requirements are access to an ST-Link compatible programmer dongle, to target the STM32 SWD programming interface, and the STM32CubeProgrammer utility. Open source alternatives to that are also available, stlink comes to mind as a good option. Once you have the module PCB popped out of its plastic casing, only three wires need tacking onto a handy set of pads to complete the connection to the programmer dongle. Pretty simple stuff.

If you’re looking for a similar project, with source immediately available, then checkout the OpenDPS project we covered a few years ago, and if you’re thinking of going crazy, building a DIY open source electronics lab, we got you covered.

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Ultra Cheap PCB Wrenches Make Perfect Kit Accessory

January 18, 2022 by Tom Nardi 43 Comments

Let’s make one thing abundantly clear. We do not, under any circumstances, recommend you replace your existing collection of wrenches with ones made out of PCBs. However, as creator [Ben Nyx] explains, they do make for an extremely cheap and lightweight temporary tool that would be perfect for distributing with DIY kits.

This clever open hardware project was spawned by [Ben]’s desire to pack an M3 wrench in with the kits for an ESP32-based kiln controller he’s developing. He was able to find dirt cheap screwdrivers from the usual import sites, but nobody seemed to stock a similarly affordable wrench. He experimented with 3D printing them, but in the end, found the plastic just wasn’t up to the task. Then he wondered how well a tiny wrench cut from a PCB would fare.

The answer, somewhat surprisingly, is pretty well. We wouldn’t advise you try to crank your lug nuts down with one, but for snugging up a couple nuts that hold down a control board, they work a treat. [Ben] came up with a panelized design in KiCad that allows 18 of the little wrenches to get packed into a 100 x 100 mm PCB suitable for production from popular online board houses. Manufactured from standard 1.6 mm FR4, they come out to approximately 10 cents a pop.

Since [Ben] has been kind enough to release his design under the MIT license, you’re free to spin up some of these wrenches either for your own kits or just to toss in the tool bag for emergencies. We’d love to see somebody adapt the design for additional sizes of nuts, or maybe figure out some way to nest them to sneak out a couple extra wrenches per board.

We’ve seen plenty of folks make cheap tools for themselves in the past, but projects that can produce cheap tools in mass quantities is uniquely exciting for a community like ours.

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