Matthias Builds A Belt Sander

[Matthias Wandel] is the preeminent YouTube woodworker, with dozens of machines constructed from wooden gears, amazing machines that produce perfect mortise and tenons, and home-built table saws and jointers. Actually building something instead of buying it is a hallmark of [Matthias]’ channel, and he’s at it again, building his own woodworking machines. This time it’s a 1″ wide belt sander. Of course anyone can go out and simply buy one of these sanders for under $100, but what’s the point in that when you can build one out of plywood and a motor you picked out of the trash?

The design of this belt sander – just like the commercial version he’s improving upon – uses three wheels to guide the 42″ long strip of sandpaper around its course. [Matthias] is using rollerblade wheels for the front wheels. Rollerblade wheels aren’t the best shape for bearings, this can be fixed by using a table saw as a lathe. Yes, [Matthias] lathes with a table saw. He’s just that good.

The rest of the frame was carefully constructed out of plywood and powered by a 1/3 horsepower furnace fan motor pulled from the trash. There are a few interesting features that make this belt sander exceptionally useful: a rounded platen behind the belt makes sanding interior corners very easy, and is something that isn’t usually found on commercial belt sanders.

You can check out [Matthias]’ video below.

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Easy Power Supply Mod Takes Control

Inexpensive bench top power supplies are great for the home hobbyist, featuring wide voltage range and current limiting for a low price. What’s not to love? The controls; most have a single-turn pot that is typically very fidgety, especially at low voltage.

The solution is to replace the factory pots with nice wire-wound 10 turn units in order to gain 10x the precision. Of course nothing is ever drop in, the new pots didn’t fit the old holes, but that is nothing a few moments with a drill can’t fix. Also the original knobs no longer fit, but that’s just an opportunity for a knob upgrade.

The end result is still a power supply with fidgety controls, but instead of holding your breath, tippy tapping knobs to get within 100mV of your target, you can dial right in to within 10mV of your target. That makes life much easier, especially on low voltage projects that may not have power regulation quite yet.

Join us after the break for a video with all the info.

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The Grid Dip Meter: Forgotten Instrument

It used to be a major rite of passage for a hardware hacker to acquire an oscilloscope. Until recently, new instruments were rarely in normal people’s budgets, so you probably made do with a used scope. Now, there are lots of inexpensive options, especially if you include low-end PC scopes and “scope meters.” Digital meters are also now inexpensive (often free at some major stores), along with signal generators, frequency counters, and even logic analyzers.

But there is one piece of test equipment you don’t see as often as you used to and its a shame, because it is a very versatile piece of kit. Admittedly, if you aren’t doing wireless work, it might not be high on your wish list, but if you do anything with RF, it is not only a versatile tool, but a good value, too. What’s it called? That depends. Historically, they went by the name “Grid Dip Oscillator” or GDO. Sometimes you’d hear it called a “Grid Dip Meter” instead. However, modern versions don’t have tubes (and, thus, no grid) so sometimes you hear them now called dip meters or maybe just dippers.

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Automated Picasso Coming To A Ceiling Near You

It’s not a day too late to switch your career from engineering to art or vice-versa! While some of us tend far towards one end or the other, some like [Chris] show us just how cool it is to walk the line… er, ceiling in this case. [Chris] took a cue from his fiancée’s latest mural project to create an automated painting jig he calls ARTbOT.

Spraying the ceiling with ARTbOT sounds like fun, but it’s a dream [Chris] needed to realize with only his spare time and small budget. Constraints aside, he’s pulled it off elegantly with a cluster of extruded aluminum tubing, a few paint sprayers, and a LabView-driven Fet triggered by encoder ticks on the drop wheel. To pain the image, it’s first binarized and scaled to accommodate ARTbOT’s 8-inch pixel size. ARTbOT then gets a boost from a scissor-lift where it can then track it’s linear position with the drop wheel to spray the pixel-pattern correctly.

[Chris] pulled this rig together to help his fiancée and her art company tackle huge canvases, in this case, large freeway underpasses. With preliminary studio tests running smoothly with ARTbOT proudly printing its name, we can’t wait to see the final piece. In the meantime, have a look at this edgy handheld alternative. Watch out mural artists! There’s an 8-bit contender in the ring these days.

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The Internet Of Reflow Ovens

Using a toaster oven to reflow solder isn’t a new idea. But [Sukasa] wanted something that had more features and improved appearace. So he married a Netduino, a toaster oven, and some solid state relays to made a clean-looking reflow oven. His goal was to have nothing look like an overt modification to a casual observer. Inside, however, the oven now has a network connection for system status via a Web browser or JSON.

The new brains of the oven are a Netduino Plus 2 and an I2C port expander that connects to a few extra I/O devices. The challenging I/O, though, is the heaters. When cold, the oven can draw over 16 amps, so a pair of 12A solid state relays in parallel handle that load. There are also two fans: one to keep the electronics cool and another on software control. An IGBT allows the controller to pulse width modulate the fan’s output. A pair of MAX31855s read the thermocouples that report the temperature.

lcdThe controller was a mashup of the existing oven’s keypad and an add-on LCD display (see right). One thing we didn’t see was a schematic. Of course, you can read the code and figure out how it is all connected and (unless you use the exact same oven) you are probably going to need to modify things to suit your particular setup, anyway.

We’ve seen other good looking reflow oven and controller builds in the past, including one with a touchscreen. It is also worth noting that you can find reflow ovens at relatively low prices now if you don’t feel like rolling your own.

Easier PCB Vias With Drill Trick And Conductive Ink

If you’ve ever made double-sided PCBs without professional equipment, you had to deal with connecting one side of the board to the other. You have a few obvious choices: 1) Rely on component leads to connect both sides (and solder both sides); 2) Create vias and solder wire to both sides of the board; or 3) Use through hole rivets. [Diyouware] had a different idea: use conductive ink. After a few false starts, they found a technique that seemed to work well.

This isn’t the first time we’ve heard of people trying conductive ink with varying degrees of success. The biggest problem, usually, is that the ink wants to run out of the hole. [Diyouware] has an interesting solution for this problem: Don’t drill the hole all the way thorough.

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GNU Radio Drives Oscilloscope

These days we are spoiled with a lot of cheap test equipment. However, you can do a lot of measurements with nothing more than an oscilloscope. Add something like a signal generator and you can do even more. One classic technique for frequency measurement, for example, is using a scope to display a Lissajous pattern. [Franz Schaefer] has a video showing how to generate these useful curves with GNU Radio.

As we pointed out earlier, GNU Radio doesn’t have to be about radio–it is really just a Python-based signal processing laboratory. [Franz] uses GNU Radio Companion to create blocks which in turn create the patterns on an old analog scope.

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