Mains Rated Solid State Relay Test Box

December 20, 2012 by Mike Szczys 30 Comments

building-a-mains-solid-state-relay-test-box

We like our nice, safe, 5V prototyping projects where the only thing that might get fried is a chip. But there are times when you want to switch appliances for one reason or another and then you’re going to want a mains rated relay. [Viktor] got tired of having exposed high voltage on the bench during the prototyping stage of these projects so he recently built a solid state relay test box.

The only thing he bought for the project was the SSR itself. To act as an enclosure he used the brick from an old laptop power supply. This is perfect for a couple of reasons. First off, it’s designed to contain high voltage if there is ever a short or other problem. Second, it’s already setup for incoming and outgoing power. He just needed to remove the guts and mount the relay. Notice that it comes with a clear plastic shield that physically separates the high voltage side from the low voltage control end. This, along with the cable routing, keeps the dangerous stuff on one side to ensure you won’t get an arc to the low voltage portion of the project.

Automated PCB Panelization

December 17, 2012 by Brian Benchoff 13 Comments

panel

Some PCB production houses – Seeed Studio and itead studio, especially – allow you to upload a gerber file and receive a printed circuit board very inexpensively. The pricing structure for these board houses is based on predesignated board sizes – 5cm square or 5×10 cm – and sometimes a project is just too small to justify buying a full 25 square centimeters of board. This is where panelizing comes in: by putting multiple copies of a circuit board on one of the available sizes you can get more boards for the same amount of money. But how to panelize your boards without the (sometimes) hassle of cutting and pasting?

[Martin] came up with a way of panelizing PCBs with just a Python script. By creating one copy of a circuit board in KiCAD, he can fire up his script and tell the computer exactly how to duplicate his circuit to fit any size board.

By his own admission, [Martin]’s script is still a little clunky, but it does allow him to edit the panelized board in KiCAD and also copies the nets so the ratsnest doesn’t go between boards.

Adventures In Mold Making And Making Your Own Enclosures

December 15, 2012 by Brian Benchoff 16 Comments

case

The folks at SC-3000 survivors have been working on a cartridge capable of storing dozens of games for the ancient Sega SC-3000 computer. The PCB works beautifully, but making a case for their cartridge left them with few options. They could use a 3D printer or simply collect a whole bunch of used cartridge cases, but making their own mold for a cartridge case was the best solution.

To create the mold for their multicart enclosure, the SC-3000 survivors first took an old, used case and made a silicone mold. While the first attempt at mold making was encouraging, several problems began to crop up due to the lack of vent holes and wiggling the mold before the resin had set. Before long, a proper technique to make resin casts was developed: use lots of resin, and don’t apply pressure or rubber bands to a curing mold.

We’re always impressed by what can be done with a few sheets of plastic, some Bondo, and the inordinate amounts of patience and sandpaper we see with other case mods and enclosure builds. the SC-3000 survivors put together an enclosure that rivals any Bondo build, and we’re happy they put out this tutorial.

Converting A Chinese Laser Cutter To Work With Mach3

December 13, 2012 by Brian Benchoff 38 Comments

laser

Like most of us, [Chris] has pined over the very, very inexpensive Chinese laser cutters available on eBay for a while now. When most of us disregarded these machines due to their inability to work with the file formats commonly used with laser cutters, [Chris] took the plunge. He was a might disappointed the included software didn’t allow him to use his machine with Mach3 CNC software, so he replaced the included electronics board with one of his own design, giving him all the features of a more expensive laser cutter at a low, low Chinese eBay auction price.

The laser cutter [Chris] bought came with the moshidraw software and controller board that according to one auction can only use BMP, JPEG, WMF, EMF, and PLT files.Wanting a board that can use more common file formats such as PDF and DWG, [Chris] built his own board to communicate with his Mach3 software.

From what we can tell, the new board works with off-the-shelf Pololu stepper drivers and is a complete drop in replacement for the moshidraw board. He’s still finalizing the design, but when the layout, BOM, and schematic are finalized, [Chris] will be putting the files up for everyone to copy. Wonderful piece of work, [Chris].

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Backyard Zamboni Keeps The Best Diy Ice Rink In Town

December 6, 2012 by Mike Szczys 15 Comments

backyard-zamboni

We’ve known people to put down a small ice rink in their back yard during the winter. But a machine to resurface these diy rinks is unheard of until now. The big name in rink resurfacing is Zamboni, the person who invented this method of keeping the ice pristine.

This has almost everything you would find on a commercial model. The tires are studded with stainless steel screws for traction. The riding lawnmower has had its grass cutting blades replaced with a single steel blade that skims the surface of the ice. There’s even a tank of water which is distributed by a copper pipe with many holes and a squeegee which drags behind the machine. The only thing this is missing is a collection system for the slush which is generated by that skimmer blade. But as you can see in the clip after the break, it does just fine without it.

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Voltage Logger Does It The Right Way

December 6, 2012 by Brian Benchoff 6 Comments

testing

The folks over at Adafruit have been busy designing an LED matrix wristwatch for a while now. The circuit works great, but since this watch is powered by a coin cell battery, they’d really like to get the power consumption as low as possible. This means they needed a test rig to measure the consumption of each firmware revision, but how exactly do you build a voltage logger that works with voltages and currents this small? It turned out to be a very interesting project, with plenty of info on how to build an accurate voltage logger for really small projects.

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An Inexpensive Manual Pick-and-Place Machine

November 24, 2012 by Jeremy Cook 20 Comments

When dealing with surface mount components, a manual pick-and-place machine is certainly a helpful device to have. Unfortunately, they can be quite expensive, so [Vassilis] came up with his own solution.

While commercial setups can cost upwards of a thousand dollars, this setup was made for less than a tenth of this cost. This one uses a simple setup of sliders and bearings available from a local hardware store. A cheap vacuum pen is used to lift the components, using an aquarium pump in reverse to generate suction. Finally, a USB microscope is used to make sure everything is placed in the correct position.

Plans are available on the site in DXF format, so you can build your own. The setup is reminiscent of a DIY CNC router, like this one that we featured a while ago. We could even see something like this serving a dual role with interchangeable heads for whatever you happen to be making that day!

Update: [Vassilis] published an video demonstration. See it after the break.

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