Review: Pine64 Pinecil Soldering Iron

There was a time when decent quality soldering irons were substantial affairs, soldering stations with a chunky base unit containing the electronics and a lightweight handheld iron for the work. That has changed with the arrival of a new breed of microprocessor controlled lightweight handheld irons. There’s a new kid on the block from a company we associate more with open-source phones, laptops, and single board computers, Pine64 have produced the Pinecil. It’s a lightweight handheld iron with some innovative features at an attractive price, but does it raise the bar sufficiently to take on the competition?

I put the Pinecil through its paces, and and although the device is fully open source, give it a teardown for good measure. Spoiler: it’s my new favorite.
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Simple AC Current Detector Built On A 9 Volt

When working around mains voltages, it can be useful to know whether a given circuit is live or not. While this can be done by direct connection with a multimeter, non-contact methods are available too. A great example is this simple wireless AC current detector from [NEW PEW].

The circuit is a simple one, and a classic. The spring from a ballpoint pen is soldered to the base of a BC547 transistor, and when held close enough to a conductor carrying AC power, a current is induced in the spring which is sufficient to turn the transistor on. The transistor then switches on a second BC547, which lights an LED. The whole circuit is built on top of a battery clip so it can be run straight from the top of a standard 9 volt battery.

It’s a circuit you’ll find all over the place, even built into many modern multimeters. It can be particularly useful to help avoid drilling through mains wires embedded in the walls of your home. Of course, if you’d like even more information about what’s lurking within your walls, consider this capacitive imaging hack. Video after the break.

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Unbricking A SEGGER J-Link V9 Debug Probe

Last year [Emil] found themselves in the situation where a SEGGER J-link debug probe suddenly just stopped working. This was awkward not only because in-circuit debuggers are vital pieces of equipment in embedded firmware development, but also because they’re not that cheap. This led [Emil] to take the device apart to figure out what was wrong with it.

After checking voltages on the PCB, nothing obvious seemed wrong. The Tag-Connect style JTAG header on the PCB appeared to be a good second stop, requiring only a bit of work to reverse-engineer the exact pinout and hook up an ST-Link V2 in-circuit debugger to talk with the STM32F205RC MCU on the PCB. This led to the interesting discovery that apparently the MCU’s Flash ROM had seemingly lost the firmware data.

Fortunately [Emil] was able to flash back a version of the firmware which was available on the internet, allowing the J-Link device to work again. This was not the end of the story, however, as after this the SEGGER software was unable to update the firmware on the device, due to a missing bootloader that was not part of the firmware image.

Digging further into this, [Emil] found out a whole host of fascinating details about not only these SEGGER J-Link devices, but also the many clones that are out there, as well as the interesting ways that SEGGER makes people buy new versions of their debug probes.

(Thanks Zelea for the tip)

Magnetic Motorized Plasma Cutter Track

Affordable plasma cutters are becoming a popular step up from an angle grinder for cutting sheet metal in the home workshop, but cutting long straight lines can be laborious and less than accurate. [Workshop From Scratch] was faced with this problem, so he built a motorized magnetic track for his plasma cutter.

Thanks to a pair of repurposed electromagnetic door looks and adjustable base width, the track can be mounted on any piece of magnetic steel. The track itself consists of a pair of linear rods, with the torch mounts sliding along on linear bearings. A lead screw sits between the two linear rods, and is powered by an old cordless drill with the handle cut off. Its trigger switch was replaced by a speed controller and two-way switch for direction control, and a power supply took the place of the battery. The mounting bracket for the plasma torch is adjustable, allowing the edge of the steel to be cut at an angle if required.

While limit switches on the end of the track might be a preferable option to prevent sliding base to hit the ends of the tracks, the clutch in the electric drill should be good enough to prevent damage if the operator is distracted.

[Workshop From Scratch] is really living up to the name of his YouTube channel, having built many of the other tools used in the video himself. Just a few examples are the XY-table, hydraulic adjustable workbench and  hydraulic shop crane. Continue reading “Magnetic Motorized Plasma Cutter Track”

Put A Hardened Edge On Mild Steel With Just A Drill Bit. Sort Of.

People have been working metal for so long that the list of tips and tricks is now nearly infinite. So it’s always a joy to pick up a new trick, especially one as simple as putting a hardened edge on mild steel using a drill bit as a filler rod.

This tip comes to us by way of [Jody], aka “The Weldmonger” on YouTube. Subscribing to his channel is a sure way to keep your welding ego in check; you may be good, but [Jody] is better, and he’s willing to share as much of his experience in video format as possible. For this tip, he starts with a cheap chipping hammer, the universal welder’s tool that helps remove the glass-like slag that forms during shielded-metal arc welding, or what’s commonly known as stick welding. The mild steel of the hammer makes it hard to keep an edge, so [Jody] pulled out his TIG welder and laid down a bead on the cutting edge using an old drill bit as a fill rod. The video below shows the process in all its simplicity.

The tool steel of the drill bit is far harder than the mild steel of the hammer, but still soft enough to take an edge, and the resulting tool is much improved. We’ve seen something similar to this before, when hard-facing filler rod was built up on the edge of a mild steel slug to make a cutter for internal weld seams. We liked that hack, but knowing the same thing can be done with something we’ve all likely got in abundance in the shop is a neat trick. Thanks, [Jody]!

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Dead Simple Time-Domain Reflectometry With Just A Battery And An Oscilloscope

“Time-domain reflectometry” sure sounds like something that needs racks of expensive equipment to accomplish. In reality, TDR is just measuring the time between injecting a pulse into a cable and receiving its echo, either from the other end of the cable or from some fault or defect along the way. It’s a useful technique, and as [Allen Wolke (W2AEW)] shows us, it can be accomplished with little more than a battery, a resistor, and an oscilloscope. And a little math, of course.

There are, of course, dedicated time-domain reflectometers, but all of them are really just elaborations of the basic principles [W2AEW] demonstrates with his simple setup. The oscilloscope is set up with a tee connector on one channel; one side of the tee is connected to the cable under test, while the shield conductor of the other side is connected to the negative terminal of a 9V battery. A resistor connected to the center conductor is used to complete the circuit, which sends a brief pulse down the test cable. The scope is set up to capture the outgoing pulse as well as the return pulse, allowing the time between the two to be measured. Some simple math gives the length of the cable, the distance to a fault, or with a little rearrangement, the velocity factor of the cable.

The video below shows the simple method at work on coax and Cat 5e Ethernet cable. It even worked on a roll of zip cable, which was a little surprising. If this technique is too simple, you can always elaborate a bit and roll your own TDR tester. Googly eyes optional, of course, but recommended.

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Railroad Rail Transformed Into Blacksmith’s Anvil With The Simplest Of Tools

One of the biggest challenges facing the aspiring blacksmith is procuring the tools of the trade. And that means tackling the unenviable task of finding a decent anvil. Sure, one can buy an ASO — anvil-shaped object — at Harbor Freight, but a real anvil is much harder to come by. So perhaps the beginner smith’s first build should be this railroad rail to anvil conversion.

Repurposing sections of rail into anvils is hardly a new game, but [The Other Finnish Guy]’s build shows us just how little is needed in terms of specialized tooling to pull this off. Other than a file, the bulk of the work is done by angle grinders, which are used to cut off the curved crown of the rail section, cut the shape of the heel, and rough out the horn. Removing that much metal will not be a walk in the park, so patience — and a steady supply of cutting wheels and sanding discs — is surely required. But with time and skill, the anvil hidden inside the rail can be revealed and put to use.

We have questions about the final result, like its lack of a hardy hole and the fact that the face isn’t hardened. We wonder if some kind of induction heating could be used to solve the latter problem, or if perhaps a hardened plate could be welded into the top to make a composite anvil. Still, any anvil is better than no anvil. More on the anatomy and physiology of these tools can be had in [Jenny List]’s article on anvils, and her whole excellent series on blacksmithing is highly recommended. [Jenny]’s not the only smith we have on staff, though — [Bil Herd] has been known to smite a bit too.

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