A Table Saw To Cut Solar Panels

February 13, 2013 by Brian Benchoff 18 Comments

saw

Steampunker extraordinaire [Jake von Slatt] loves the idea of solar-powered garden lights soaking up the sun’s rays during the day and powering a LED in the evening. Commercially available solar lanterns, as [Jake], you, me, and everyone else on the planet have discovered, are universally terrible and either don’t have solar panels large enough to charge a battery, or only last a year or so. [Jake]’s solution was to make his own solar lanterns and in the process he came up with a great way of cutting his own solar panels.

[Jake] turned to ebay to source 100 3″ x 6″ solar panels for about $30. These are broken panels, factory rejects, but still are able to produce the 0.5 Volts they should. Since these are rather large panels for a solar lantern, [Jake] needed a way to cut these panels into manageable sizes.

To cut the panels, [Jake] made a box to fit a Dremel with a right angle attachment and a port for a vacuum cleaner. There’s a sled for the panels with markings at 40, 80, 75, and 150 mm so the panels can be quickly cut to size with a diamond cutting wheel.

After the boards are cut, [Jake] checks them out with a multimeter to be sure they’re producing the half volt they should. After that, it’s a simple matter of soldering them together and adding them to his solar lanterns.

DIY Forklift For The Home Shop

February 13, 2013 by Brian Benchoff 21 Comments

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[Robert] does a fair bit of metal casting, and of course that means carrying around hundreds of pounds of sand, scrap, and other materials. He came up with a great solution to the inevitable back pain: a small, workshop-sized forklift able to carry around a half ton pallet.

In the actual build thread for this forklift, [Robert] goes over the design. The lift is designed to fit inside a 30″ x 7′ door frame, but is more than capable of hoisting hundreds of pounds over the operator’s head. It’s driven by two electric wheelchair motors with power provided by two car batteries. There’s also a clever bit of engineering that went into tipping the forks: instead of a hinge on the mast, [Robert] used a linear actuator on the rear wheels to put the forks at an angle.

It’s a great build, and since [Robert] does metal casting, there’s a whole bunch of custom metalwork that really adds to the build. After the break you can see a video of [Robert]’s forklift transferring a pallet weighed down with 5 gallon buckets from one really high shelf to another. The job doesn’t take long and doesn’t require any lifting, so we’ve got to hand it to [Robert] for this build.

Continue reading “DIY Forklift For The Home Shop” →

Reflow Oven Courtesy Of Hurricane Sandy

February 10, 2013 by Brian Benchoff 7 Comments

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The Makerbar, Hoboken’s Hackerspace, was in desperate need of a reflow oven. Hurricane Sandy did a number on a whole bunch of household appliances, so when [Kush] saw a neighbor throw out a broken toaster oven, the Makerbar crew sprung into action.

The storm waters shorted the electronics board, fried the existing controls, and basically turned the oven into a metal shell with heating elements. It was the perfect platform for a toaster oven – every part that was going to be thrown out was already destroyed.

[Zach] over at the Makerbar ordered the Sparkfun reflow toaster conversion kit along with a few arcade buttons and set to work. After plugging the heating elements into the mains power to make sure they still worked, [Zach] attached these elements to the relay on board the controller. Three arcade buttons were wired up to the controller, and a whole bunch of code was written.

With the included thermocouple, [Zach], [Kush], and the rest of the Makerbar gang now have a very accurate and reliable reflow oven. There’s also settings for Sculpey clay and shrinky dinks, just in case anyone at Makerbar is feeling a bit creative.

Building A Tool To Measure Melting Point

February 8, 2013 by Mike Szczys 5 Comments

melting-point-apparatus

When working with chemical reactions it may be necessary to test the purity of the components you’re using. This is especially true with hobby chemists as they often acquire their raw materials from the hardware store, garden center, or pool supply. [Ken] figured out how to get around the $500 price tag of a commercial unit by building this DIY melting point test apparatus.

In this image he’s using a thermocouple to monitor the temperature of the melting surface, but mentions that you can do this with an inexpensive dial thermometer and will still have great results. That melting surface is the hexagonal head of a bolt which he drilled out to provide a concave surface for the test compound. Inside the PVC pipe is the heating element from a 40W hot glue gun. He wrapped it in fiberglass fabric which is sold in the plumbing supply to protect the area around pipe joints during soldering. The rotary light dimmer feeds the electricity to the element, allowing for adjustments to the ramping speed.

A Constant Resistance Dummy Load Design

February 8, 2013 by Mike Szczys 21 Comments

constant-resistance-dummy-load

This constant resistance dummy load has not yet been tested in the real world. [YS] was inspired to come up with the circuit after reading Wednesday’s Re:load dummy load post. That was a constant current load, not a constant resistance load. [YS] started with the schematic for the Re:load and made his changes to arrive at this.

For him the exercise was just to alter the design to achieve constant resistance. He didn’t actually build and test the hardware because he doesn’t really have a need for it. This image was exported from Proteus, which includes a ProSPICE circuit emulator. His slides run through test voltages from 5V to 50V, maintaining a constant 10 Ohm resistance.

When studying this project we needed a little refresher on the different varieties of dummy loads. We found this post very informative about the differences and uses of Constant Current, Constant Power, and Constant Resistance (Impedance) loads.

PCB Production Workshop Means Everyone Gets An Arduino

February 7, 2013 by Brian Benchoff 3 Comments

nano

Over at the LVL1 hackerspace in Lousiville, [Brad] is putting together a workshop on etching PCBs at home. [Brad] wanted all the participants to take home something cool, so he settled on an Arduino clone as the workshop’s project.

The clone [Brad] used is the Nanino, a single-sided board we’ve seen before. Unfortunately, there aren’t any CAD files for the Nanino and doing a toner transfer with the existing PDFs was a pain. This led [Brad] to redraw the Nanino in Diptrace and put the files up for everyone to grab.

In his workshop, [Brad] is going to be using a laser printer, hydrogen peroxide, and HCl. one of the most common setups for home etching. If you’re in the Louisville area, you can make your own Nanino with a home etching workshop on March 16th. Be careful, though: those LVL1 guys are pretty weird; they have a moat and are building a homicidal AI.

Re:load, An Open Source Dummy Load

February 6, 2013 by Eric Evenchick 14 Comments

When testing power supplies or LEDs, a constant current dummy load is needed. These devices will draw a constant amount of current, regardless of the voltage at the input terminals.

[Nick] was looking for a load to test out a power supply, and found commercial offerings to be too large, too powerful, and most importantly, too expensive. This lead to the design of the Re:load, his open source alternative.

Like other constant current sources, the Re:load uses an opamp to control a pass element. While most constant current loads will just use a transistor, [Nick] opted for a BTS117 smart low side switch IC. This device has a built in current limiter, over-voltage protection, over-temperature protection, and short circuit protection, which makes it much safer. The project write up goes into detail on how the device works.

If you need a constant current load, [Nick] is selling kits on Tindie. All the design files are available on Github so that you can build your own.