Measuring Capacitors Over Their Working Voltage

Ceramic capacitors are small, they don’t leak, they’re convenient, but they are downright strange. Certain types of caps will lose their capacitance depending on the voltage they’re operating at. If you’re using ceramic caps for filters, DC to DC power supplies, bypass caps, or anything where you need an exact capacitance in a circuit, this can be a problem.

[Mathieu] has come up with a tool that’s able to measure the capacitance of a cap over its entire working range. He’s calling it the OpenCVMeter, and although the name might be slightly confusing, the functionality is not. This little box will measure the capacitance of a part over a voltage range from 1.3 to 15.5V.

By attaching the SMD tweezers or test clips to a capacitor, the OpenCVMeter ramps up the voltage and measures the capacitance of the part through the test cycle. This data is then dumped to a Chrome app – a surprisingly popular platform for test equipment apps – and a determination of the cap’s ability will to work in a circuit is displayed on the screen

If you’ve ever tooled around with antique electronic equipment, you’ll know the first thing to go bad in any piece of equipment are caps. Either caps had extremely loose manufacturing tolerances back in the day or the values really were that critical, but a dodgy cap can bring down everything from tube amps to computers. It’s a very neat tool, and something that doesn’t really exist in a single dedicated device.

A Handheld CNC Router

Over the last few years, the state of the art in handheld routers has been tucked away in the back of our minds. It was at SIGGRAPH in 2012 and we caught up to it at Makerfair last year. Now, it’s getting ready for production.

Originally called Taktia, the Shaper router looks a lot like a normal, handheld router. This router is smart, though, with the ability to look at a work piece marked with a tape designed for computer vision and slightly reposition the cutter in response to how the user is moving it. A simple description doesn’t do this tool justice, so check out the video the Shaper team recently uploaded.

With the user moving the Shaper router over a work piece and motors moving the cutter head, this tool is able to make precision cuts – wooden gears and outlines of the United States – quickly, easily, and accurately. Cutting any shape is as easy as loading a file into Shaper, calling that file up on a touch screen display, and turning on the cutter. Move the router around the table, and the Shaper takes care of the rest.

Accuracy, at least in earlier versions, is said to be on the order of a hundredth of an inch. That’s good enough for wood, like this very interesting bit of joinery that would be pretty hard with traditional tools. Video below.

Thanks [martin] for the tip.

Continue reading “A Handheld CNC Router”

Hacking a $100 Signal Generator

Signal generators are a useful piece of kit to have on your electronics bench. The downside is that they tend to be rather expensive. If you have $100 to drop on a new toy, the MHS-5200A is a low cost, two channel, 25 MHz generator that can be found on eBay.

The downside is the software. It’s an ugly Windows interface that’s a pain to use. The good news is that [wd5gnr] reverse engineered the protocol so you don’t have to. This means other software can be developed to control the device.

When connected to a computer, this function generator shows up as a virtual USB serial port. The documentation that [wd5gnr] assembled lists all the serial commands you can send, and what they do. If you aren’t into manually setting waveforms from a serial terminal (who is?) there’s a tool for doing that automatically on Github. This takes in a CSV file describing a waveform, and programs the generator to make it for you.

The software is also compatible with Waveform Manager Plus, a free GUI tool for defining waveforms. Putting this all together, you can have a pretty capable waveform generator for less than $100.

Hacklet 53 – Quick Tool Hacks

They say necessity is the mother of invention. Have you ever been right in the middle of a project, when you realize that you could hack up a simple tool which would make your current task easier? Maybe it’s a coil winder, or a device to hold .100 headers straight in their holes. Faster than you can say “Arabian Nights”, you’re working on a project within a project. It might not be pretty, but it gets the job done. This week’s Hacklet is all about quick tool hacks – little projects that help out around the shop or hackerspace.

lampieWe start with [theonetruestickman] and Magnificent Magnifier LED Coversion. [theonetruestickman] picked up an articulated magnifier lamp at Goodwill for $4. These lamps are a staple of benches everywhere. The only problem was the switch and fluorescent tube were both failing. [theonetruestickman] didn’t feel bad for the lamp though. He pulled out the tube, ballast, and starter, replacing them with LEDs. He used 12 V 3 watt LED modules to replace the tube. Three modules provided plenty of light. An old wall wart donated its transformer to the effort. Since these LED modules are happy running on AC, no bridge rectifier was necessary. The modernized lamp is now happily serving on [theonetruestickman’s] workbench.

toolNext up is [Kwisatz] with Pick Up tool hack. [Kwisatz] is a person of few words. This whole project consists of just two words. Specifically, “syringe” and “spring”. Thankfully [Kwisatz] has provided several pictures to show us exactly what they’ve created. If you’ve ever used one of those cheap pickup tools from China, you know [Kwisatz’s] pain. The tiny piece of surgical tube inside the tool creates a feeble vacuum. These tools only hold parts for a few seconds before the vacuum decays enough to drop the part. [Kwisatz] kept the tip of the tool, but replaced the body with a syringe. A spring is used to create just the right amount of vacuum to hold parts on while they are being placed.

fume[Dylan Bleier] made his shop air a bit safer to breathe with a simple fume extractor for $20. Solder and flux create some nasty smoke when heated. Generally that smoke wafts directly into the face of the hacker peeking at the 0402 resistor they are trying to solder. A bit of smoke once in a while might not be so bad, but over the years, the effects add up. [Dylan] used two 120V AC bathroom fans, some metal ducting, plywood, and a bit of time to make this fume extractor. [Dylan] is the first to say it’s not UL, CE, or ROHS compliant, but it does get the job done. He even added a screen to keep bugs from flying in from the outdoor exhaust port.

helix[ftregan] needed to wind a helical coil for an antenna, so he built Helix Winder. Helices are essentially springs, so that should be easy, right? Turns out that making a nice uniform helix is not the easiest thing in the world. The helix winder is a jig which makes winding these special coils much easier. Holes are drilled at a specific angle in a wooden block. The wire is fed through that block and rolled onto an aluminum tube. Rotating the block on the tube forces the wire into the helix shape. The only downside is that each winder is only good for once dimension of helix.

I’ve noticed that some of these quick hacks don’t get as much love as they deserve over on So if you notice a cool hack like this, drop a comment and give the project a skull. If you want to see more of these hacks, check out our new quick tool hacks list! See a project I might have missed? Don’t be shy, just drop me a message on That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of!

Machine Metal With Electricity: An EDM Attachment For 3D Printers

[SuperUnknown] has revealed a secret project he’s been working on. He’s cooked up an EDM attachment for 3D printers, or any CNC machine for that matter. Electrical Discharge Machining (EDM) is a method of using sparks to machine metal. EDM isn’t a new technology, in fact commercial machines have been around since the 1960’s. If you’ve ever had an arc scar up your multimeter probes, you’ve unwittingly done a bit of EDM.

The theory behind EDM is simple: High voltage between the tool and workpiece causes sparks to jump between them. Each spark erodes the workpiece (and the tool). Big EDM machines perform their magic in a liquid which acts as both a dielectric and a flushing medium. This liquid can be anything from deionzed tap water to specially formulated oil. [SuperUnknown] is using good old-fashioned tap water.

edm-roughAs you can imagine, a single spark won’t erode much metal. EDM machines fire tens of thousands of times per second. The exact frequencies, voltages, and currents are secrets the machine manufacturers keep close to their chests. [SuperUnknown] is zeroing in on 65 volts at 2 amps, running at 35 kHz. He’s made some great progress, gouging into hardened files, removing broken taps from brass, and even eroding the impression of a coin in steel.

While we’d love to say this is a free open source project, [superUnknown] needs to pay the bills. He’s going with crowdsourced funding. No, not another Kickstarter. This project is taking a different route. The videos of the machine will be uploaded to YouTube and visible to [superUnknown’s] Patreon supporters. They will also be available for rent using YouTube’s new rental system. [SuperUnknown] has pledged to figure out a way to make the content available for starving college students and others with limited incomes.

Based upon his previous adventures with lil’ screwy, his homemade 100 ton press, and various other projects on the Arduino verses Evil YouTube channel, we think [superUnkown] has a pretty good chance of making home EDM work. Click past the break to see two videos of the 3D printer EDM toolhead in action. We should mention that [SuperUnknown] is rather colorful with his dialogue, so make sure you’re using headphones if you’re at work.

Continue reading “Machine Metal With Electricity: An EDM Attachment For 3D Printers”

Hackaday Prize Entry: Python Powered Scientific Instrumentation

A common theme in The Hackaday Prize and in general is tools to make more tools. There are a lot of people out there trying to make the next Bus Pirate, and simply measuring things is the first step towards automating a house or creating the next great blinkey invention.

In what is probably the most capable measurement system in the running for this year’s Hackaday Prize, [jithin] is working on a Python Powered Scientific Instrumentation Tool. It’s a microcontroller-powered box containing just about every imaginable benchtop electronics tool, from constant current supplies, LCR meters, waveform generators, frequency counters, and a logic analyzer.

This project is stuffed to the gills with just about every electronic tool imaginable; there are programmable gain amplifiers, voltage references, DACs and constant current sources, opamps and comparators, all connected to a bunch of banana jacks. All of these components are tied up in a nifty Python framework, allowing a bunch of measurements to be taken by a single box.

If that’s not enough, [jithin] is also working on wireless extension nodes for this box to get data from multiple acquisition points where wires would be unfeasible. This feature uses a NRF24L01+ radio module; it’s more than enough bandwidth for a lot of sensors, and there’s enough space all the wireless sensors you would ever need.

The 2015 Hackaday Prize is sponsored by:

Hackaday Prize Entry: The MultiSpork

If you’re working on a mobile project – a robot, something outside, or even your car – you don’t want to bring an oscilloscope, logic analyzer, signal generator, or any other piece of equipment that should stay on the bench. For his Hackaday Prize Entry, [Pierce Nichols] is working on the electronic equivalent of a Leatherman: something small and portable that also does just enough to get by in a pinch.

The MultiSpork, as [Pierce] calls his device, is a single WiFi enabled board that’s completely portable. With the addition of a $50 Android tablet, it’s very close to a complete electronics lab in a box.

The heart of the MultiSpork is a new chip from Maxim, the MAX 11300. This chip has 20 pins that can be used as a 12-bit ADC, a 12-bit DAC, or as GPIOs. it’s a logic analyzer, signal generator, oscilloscope, and a Bus Pirate in a single chip. As far as the rest of the board goes, [Pierce] is forgoing any notion of a hardware freeze and changing the Atmel microcontroller over to a TI CC3200 chip that will be coming out soon.

[Pierce] put together a short video describing the MultiSpork; you can check that out below.

The 2015 Hackaday Prize is sponsored by:

Continue reading “Hackaday Prize Entry: The MultiSpork”