DIY Spot Welder Makes Metalwork Easy

At Hackaday, we’ve seen enclosures built out of just about every material. From wood, glass, epoxy resin, plastic, and even paper, all these different types of enclosures provide some interesting properties. Sometimes, though, you need an enclosure made out of metal and welding together steel cases isn’t exactly easy or cheap. [manekinen] came up with a really great solution to the problem of welding together sheet metal. It’s a very easy to build spot welder perfect for fabbing steel cases.

The core of the build is a transformer pulled from a Technics stereo amplifier. [manekinen] removed the stock secondary winding and rewound the transformer four turns of 35mm ² wire (about 2 AWG). This made the transformer put out 2.6 Volts a 1 kA – more than enough to weld 22 ga sheet.

For the control mechanism, [manekinen] put a limit switch on the electrode arm and wired that to a timer. A knob on the front of the welder allows him to vary the time the welder is on from 0 seconds to 4 seconds.

The results are fantastic – trying to rip apart a weld only results in the metal itself tearing; exactly what you want to see in a welder. It’s a great build made even more fantastic by the welder building its own enclosure.

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Semi-professional Board Assembly For Your Workshop

[Zach Hoeken] has the answer to assembling multiple surface mount PCBs in the home workshop. It’s certainly not for everyone. But if you’ve ever thought of marketing your own small runs he has the equipment and methodology you need.

He had tried using hacked together equipment, but after encountering a range of issues he finds the investment in a few key items saves time and money in the long run. The first is a precision tooling fixture block; that metal plate with a grid of holes that makes up the background of the image above. It comes with machined pegs which fit the holes perfectly, and as you can see, his panel of 16 boards include tooling holes that line up with the fixture. Once in place, a steel solder stencil is aligned with the board using its own tooling holes. The alignment of the stencil and its uniformed thickness ensure that the perfect amount of solder paste is easy to apply with a squeegee. [Zach] hand places his components but he did invest in a proper reflow oven to make the soldering a set and forget process.

DIY Pick And Place Builds Boards, Is Awesome

In what can probably be attributed to the pains of placing a lot of SMD components, [gravelrash] built his own home-made pick and place machine.

Instead of being frustrated with tweezers, stereo microscopes, and having an inordinate amount of concentration, [gravelrash] built a pick and place machine from a Chinese CNC router. The build doesn’t use automated feeders for its reels of parts. Instead,[gravelrash] picked up five manual feeders from eBay, allowing his pick and place to hold 25 different reels of components.

There is, of course, a vacuum pump for sucking up SMD parts and a two-axis gantry capable of moving components from reel to board. The software is Mach3, a program normally used with spinning cutters to mill away wood, metal and plastic. [gravelrash] replaced this motor with a few vacuum controlled needles to pick up, move, and drop components onto the board.

While the build may not be as fast as some other pick and place machines we’ve seen, it’s almost as fast as hand-placing components with the added bonus of not tearing your hair out over very tiny parts.

Tip ‘o the hat to [Alexander] for sending this one in.

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Tiny OLED Oscilloscope Gets A Fancy Case

[Gabriel Anzziani] has just unleashed a newer, more convenient version of his Xprotolab portable oscilloscope, logic analyzer, and function generator. It’s up on Kickstarter, and the price is actually very nice for a tool of this caliber.

We first saw the Xprotolab early last year and ran into [Gabriel] at this year’s World Maker Faire in New York. On both occasions we were impressed with the size and capability of this very, very small OLED-display oscilloscope and general breadboarding Swiss army knife.

The Xprotolab features a two-channel, 200 kHz oscilloscope, 8-input logic analyzer, and an arbitrary waveform generator that should be good enough for all your breadboarding adventures. On top of that, the Xprotolab can sniff SPI, I2C, and UART protocols, and even has a small spectrum analyzer tucked away in a device small enough to lose in your pocket.

The updated-for-Kickstarter Xprotolab features an enclosure with a LiPo battery good for 12 hours of use per charge. Sure, it’s not a bench full of old HP and Tektronix gear, but for the budding maker, this seems like a very useful tool indeed.

Repairing A Junked Signal Generator

We must be walking past the wrong dumpsters because we certainly haven’t encountered equipment like this just waiting to be salvaged. [Shahriar] found an HP 8648C Synthesized Signal Generator while he was ‘dumpster diving’ and set out to fix the malfunctioning lab equipment. He posted a 1-hour video on the project, which you can find embedded after the break. The actual fix happens in the first half, the rest of the video is spent testing the resurrected device.

The back corner of the case has been dented, which may be the reason this has been thrown out. When it is first powered it emits an unpleasant screeching noise and the user interface doesn’t do anything. [Shahriar] says he recognizes the sound as a malfunctioning switch-mode power supply. Sure enough, when disconnected from the main board it still makes the noise. It turns out there’s a huge electrolytic capacitor the size of a stack of poker chips which has come loose from the PSU board. When it’s resoldered the device fires up as expected.

Now how are we going to find a digital capture oscilloscope that just needs to have its PSU reassembled?

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Giving The Rigol DS1052E ‘scope A Spectrum Analyzer

Like a lot of hardware tinkerers, [dexter2048] has a Rigol DS1052E oscilloscope sitting on his bench. One day when trying to coax some information out of the FFT setting, [dexter] threw his hands up in frustration and decided to write a file viewer with FFT spectrum analysis. The resulting viewer gives this very capable and inexpensive oscilloscope a spectrum analyzer.

[dexter2048]’s app is able to capture signals from 0 Hz to 500 MHz and demonstrated this fact by sticking a piece of wire into one of the Rigol’s inputs. The resulting waveform is then sent to a computer where [dexter] got a nice picture of the radio spectrum between 82MHz and 114MHz. In his graph, you can clearly see the FM radio stations that can be picked up in [dexter]’s lab.

This small modification to the Rigol DS1052E oscilloscope it the latest in a long line of hacks that give this wonderful, inexpensive scope double the bandwidth, data collection via Python, and even a homebrew version of Pong. Anything that provides new functionality for old gear is great news to us, and we look forward to many, many more 1052E hacks in the future.

Tip ‘o the hat to [Murlidhar] for sending this in.

Oscilloscope VFD Repair Like Doing Brain Surgery On Yourself

[Jerry Pommer] has an old Tektronix 2236 that is having some issues. Just to the right of the top corner of the screen is a VFD display that is used to show various numerical measurements. Unfortunately this has stopped working, so he made the oscilloscope probe itself in order to trouble-shoot the situation.

The entire repair process was filmed and you can see the 42-minute job embedded after the break. There’s a lot of stuff crammed inside that oscilloscope, and we see a tour of it all at the beginning of the video. Once [Jerry] gets down to business he traces the problem to a JK Flip-Flop used to feed the display. The output appears correct at first, but the clock signal is not functioning as expected. His solution is to use an MSP430 chip to replace the Flip-Flop functions.

The confidence to try this repair was sparked by [Todd Harrington’s] car-stereo VFD repair video.

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