A Ham Radio Receiver, Manhattan Style

September 4, 2011 by Mike Nathan 3 Comments

If you’ve never heard of “Manhattan Style” circuit construction, you’re not alone. Popular in ham radio circles, the process looks nicer than straight dead bug style circuit building, but not as involved as etching your own PCB – consider it a nice middle of the road solution.

This type of construction is often used to build circuits inside enclosures that are made of copper clad, which is a somewhat common practice among ham radio operators. Manhattan Style circuits are built using glued-on metal pads to which components are mounted. One might think that the large pads you see in the image above would limit you to through-hole components, but that’s definitely not the case. A wide array of SMD pads are available in common pin configurations as well, allowing you to use pretty much any type of component you prefer.

While it might not be appropriate for every project you work on, Manhattan Style circuits and copper clad boxes definitely add a nice touch to certain items, like the Wheatstone Bridge Regenerative Receiver you see above.

[via Make]

Delta Robot 3D Printer

September 4, 2011 by Brian Benchoff 22 Comments

Sometimes, not all our builds work out the way we hoped. That’s what happened to [Rob] and his attempt at a Delta robot that does stereo lithography. A Delta robot is capable of very fast and precise movements, so [Rob] slapped a laser module on the end of the arms. After putting some UV curing resin in front of the laser, he was left with a blob of goo and we’re trying to figure out why.

[Rob] thinks the admittedly terrible print quality was due to diffraction and the reflective build plate. If this were the case, we’d agree with the assessment that adding some dye to the resin would help. Some commentors on [Rob]’s blog have suggested that he’s running the laser too slowly. It’s a shame [Rob] scrapped his build and turned it into a plain-jane X & Y axis build. Delta robots can be really damn fast, and adding a printer to one might mean prints that take minutes instead of hours. There are a few people working to get a Delta RepRap off the ground, but this project still has another prototype or two before that happens. Check out [Rob]’s attempt at Delta robot stereolithography after the break.

Thanks to [techartisan] for sending this one in.

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Engine Hacks: Homebuilt Solid State Ignition Module

September 4, 2011 by Nick Schulze 66 Comments

[Dan] wanted to learn a bit about solid state ignition in engines; to get started he needed a test subject, so he decided he would upgrade his old 12 horsepower lawnmower.

Originally the lawnmower engine used a magneto coil ignition system, magnetos are simple and very common in lawnmowers. The magneto is designed to produce a high voltage spike when influenced by a magnetic field. A magnet is attached to the engine’s crankshaft to time the voltage spikes, these spikes are fed directly into the spark plugs to cause ignition, this is why you don’t need a battery. [Dan] explains how the solid state ignition works on his site as he goes through the build details. Essentially it uses a hall effect sensor to detect a spinning magnet on the crankshaft for timing, and a transistor and battery to fire the spark plugs for ignition.

Once he got his circuit up and running on a breadboard, he fitted the entire system into a neat plastic box and fixed it to the front of the lawnmower, as if it was meant to be there all along.

PIC-based Voice Recorder

September 3, 2011 by Mike Szczys 34 Comments

[Vinod] just finished building a voice recorder and it turned out even better than he thought it would. The video after the break shows him recording what is surely one of your favorite songs from his cellphone and then playing it back. The audio quality does sound quite good for a project with very few components.

A PIC 16F877A makes up the majority of the build. Its ADC is used to capture the incoming line from an amplified microphone input (you’ll find that amp schematic half way through his post). He’s storing the data on an MMC card, which was a bit of a hack since the PIC has limited RAM to manage that overhead. The stored data is in a raw format, as the card is not accessed using a file system. This makes it easy to record at a high bit rate, leading to better audio quality. Playback consists of connecting a speaker via a low-pass filter and amplifier circuit to the hardware PWM output on the PIC.

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Weekly Roundup 09/03/11

September 3, 2011 by Jack Buffington No comments

In case you missed them the first time, here are our most popular posts from this past week.

Our most popular post was about a ‘flashlight’ build. We are using the word flashlight loosely since this monster can draw up to 500 Watts!

Our next most popular post was about another [Jörg Sprave] project where he has built a very large slingshot that can shoot shot puts. He then proceeds to destroy a car with it.

This post describes an open-source Segway. It is built around an ATmega644 has a nice professional look to it.

If you live out in the country and have a problem with rats, this post could be for you. In this post, we look at [Snypercat’s] build where she has mounted a camcorder onto the scope for her pellet gun and also attached an infrared light source so that she can snipe rats at night.

Finally, we have a post about a custom V-12 Kawaskai Voyager. If you are looking for a great way to draw attention at your next motorcycle rally, this post might give you some inspiration.

Engine Hacks: Convert Your Yard Tools To Run On Steam!

September 3, 2011 by Jack Buffington 45 Comments

Engine Hacks Theme banner

Are you tired of doing things the efficient way when using your lawn equipment? Look no farther. Here are some engine hacks where regular internal combustion engines have been modified to work on steam or compressed air. Surprisingly, all it takes to do this is to remove the carburetor and replace it with a steam line and to modify the valve timing.

First up is a lawn mower that runs on steam posted by [dquad]. This one is pretty great because it just looks so wrong. In [dquad’s] own words: “I am surprised by the fact that nothing at all failed during this test – other than a wheel catching fire!”

http://youtu.be/7qGI6Ogiasg

Check out some other examples of engines converted to run on air or steam after the break…
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POV Keychain From Prototype To SMD Board

September 2, 2011 by Mike Szczys 9 Comments

[Augusto] wrote in to tell us about his keychain-sized persistence of vision project. He built the original prototype on some protoboard, using a PIC 16F627 to drive eight LEDs. Synchronization is managed by a tilt sensor on the board that starts the strobing to match the direction the board is traveling. This is a similar setup as the POV device that used an accelerometer, but it should be quite a bit easier to code for the tilt switch.

Once [Augusto] had the hardware dialed in he set to work laying out a surface mount design. The two AAA batteries were traded for a single 3V coin cell, which is on the back side of the board you see above. This is his first attempt at working with surface mount components and we think he did a great job. Check out the POV in action in the video after the break.

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