Squeezing The Juice Out Of Some AA Batteries

February 27, 2012 by Mike Szczys 75 Comments

[Ray’s] breadboard power supply lets you drain the last traces of power from ‘dead’ AA batteries. Electronics that are powered off of disposable alkaline batteries have a cutoff voltage that usually leaves a fair amount of potential within. Since many municipal recycling programs don’t take the disposables (you’re just supposed to throw them in the trash!) we love the idea of squeezing them for prototyping use.

His design uses just one IC, the MCP1640, along with a handful of passive components. The chip is a boost converter with a startup voltage of just 0.65V, which means the batteries themselves – normally starting life above 1.5V – can be used until they drop to about 0.3V each.

Above you can see the kit he is selling. But it’s an open source project and the circuit is so simple we’re sure you can build your own. Add that boost converter chip to your next parts order for around $0.40.

[Ray] made a nice demo video for the device which you can see embedded after the break.

Continue reading “Squeezing The Juice Out Of Some AA Batteries” →

Cheap And Easy Logic Signal Generator

February 27, 2012 by Brian Benchoff 8 Comments

While function generators or analog signal generators are ubiquitous in their utility, we haven’t seen much of logic function generators on Hack a Day. Luckily, [Dilshan] sent in a really neat 8-channel signal injector that is amazingly simple to build and comes with a great front end for editing patterns from your computer.

The hardware portion of the build is kept to a minimum with a PIC18F chip, USB socket, and header pins as the only major components. This board serves as the hardware output for the Kidogo software. This software provides a very nice interface to generate 5 volt logic signals on eight separate channels that will immensely help exploring your digital world.

With a great interface and very easy to build hardware, we can easily see the Kidogo hardware finding its way onto workbenches around the world. We’re tempted to build our own version using an AVR, but we would hate to ruin such a simple but useful tool.

Heatless Compressed Air Dryer

February 22, 2012 by Mike Szczys 25 Comments

The pressurized air from a standard air compressor is fine for most uses. But some applications like plasma cutting call for low-humidity air and the hardware available to facilitate this can cost a bundle. [Roland] and his cohorts at TX/RX Labs (a Houston, Texas Hackerspace) just built this air drying system.

It works using a desiccant; a substance that sequesters moister. It’s the stuff in those little packets you find in shoe boxes and the like with a warning that you shouldn’t eat it. The image above shows two chambers which house the desiccant. Only one is used at a time, so that as it’s ability to remove moisture drops, the system can switch over to the other chamber. There’s even an automatic recharging system built in that uses a portion of the dried air to remove the humidity from the unused desiccant chamber.

There’s a functional diagram at the link above. It’s resolution is low enough that the text is almost unreadable but we’ve asked [Roland] if he can repost the image. This seems like a build in which other hackerspaces will be interested.

Tired Of The Normal Use For Your Toothbrush? Why Not An Engraving Tool?

February 21, 2012 by Jeremy Cook 10 Comments

Hardware hackers and makers like us may not be well known for our excellent hygiene habits, but after [Dan]’s creation, no one can claim he doesn’t know how to use one! Either out of a total disdain for tooth care, or hopefully, after using one properly for many months, [Dan] decided to turn his electric toothbrush into an engraving tool!

At around $4 and meant for cleaning plaque off teeth, this tool isn’t the most powerful engraver on the block, but is capable of good work on softer material such as acrylic. Be sure to check out the heart that was made with this improvised tool that introduced us to [Dan]’s work.

This is really a clever use of your resources, and the article gives a nice account of how the toothbrush was modified with pictorial directions. Besides it’s use as an engraving tool, this might give someone other ideas for alternate toothbrush uses. For another neat alternate home-item use, why not check out how to repurpose an air freshener as a camera trigger?

Kicad Symbol Generating Script Shows Promise

February 17, 2012 by Mike Szczys 17 Comments

Kicad is a fantastic PCB layout tool. We think creating a part for use with Kicad is in many ways easier than in Eagle, but it never hurts to have a few shortcuts. Here’s a new way to quickly get your parts into the schematic editor. It’s a Python script that generates symbols from an XML input file. You create the XML file with a list of all the pins on your part and the function they will serve. The Python script will then format that as a library file which can be imported by Kicad.

It’s a little bit clunky due to the number of steps in the process. But it is possible to use a CSV file generated in a spreadsheet program to create the XML needed by the script. We’ve used the online component builder ourselves, and appreciate the possibility of mass pin assignments instead of the drop-box for every pin as used by the web interface. One time we were 20 pins into the naming process and accidentally refreshed the page… ugh!

The code is available in their git repository, with a description of the XML format, and a wiki tutorial outlining the component building process. After you give it a try we’d love to hear what you think in the comments.

Let There Be Light Inside Your Epilog Laser Cutter

February 14, 2012 by Mike Szczys 15 Comments

[Bradley Gawthrop’s] biggest gripe about his laser cutter is the lack of Mac support. We don’t think we’d have any gripes if we owned one of these (yeah, that’s a lie…) but we can understand his second biggest issue which is the inability to see the work piece once it’s inside the machine. He figured out a very easy way to light the area as the cutter gets to work.

It occured to him that the optical head is always directly above the part of the work piece he was interested in seeing. He had been using a flashlight to shed some light, but what if he just added lighting to that head? The circuit is certainly nothing hard; some LEDs, resistors and a power source will do the trick. But routing the power is where things get more difficult. You need flexible wiring strung just right so as not to restrict motion on the X/Y axes. Most of his time was spent routing some 14 gauge stranded speaker wire for this task. He added his own 5V DC supply to power the adhesive LED strip which enjoys a resting place on the bottom rail of the head unit. Boom, problem solved.

Take A Picture Of A Bang With A Camera Sound Trigger

February 14, 2012 by Brian Benchoff 6 Comments

We’ve featured dozens of digital camera triggers over the years. Very rarely do we come across one as well designed as [Viktor]’s ‘lil bang sound trigger that snaps a picture whenever a microphone picks up a loud noise.

[Viktor]’s build is based around a PIC16F microcontroller with an LM386 amp connected to a microphone. On the front of the device, the right knob controls the sensitivity of the microphone and the left knob sets the delay between detection and the trigger.

The ‘lil bang trigger connects to the camera through an opto-isolated 3.5 mm jack that is compatible with all the fancy Canon and Nikon DSLRs. The delay between sound detection can be changed from 0 to 255 ms, allowing for precise control over a high-speed photography rig.

All this work comes after the light-activated trigger [Viktor] built for taking pictures of lightning. The sound-activated version wouldn’t work for lightning pics, but he thinks it could be useful for collision or explosion photographic studies. Check out the video of [Viktor]’s ‘lil Bang in action after the break.

Continue reading “Take A Picture Of A Bang With A Camera Sound Trigger” →