Simple Touch Sensor And Other Lessons

February 3, 2011 by Caleb Kraft 21 Comments

[HankDavis] sent along this link to a video showing a tutorial on how to make touch sensors using a “darlington pair”. In the video we are taken through the idea and how we’re going to construct it. [Thad]explains in detail how this works in simple terms and illustrates it clearly. Unfortunately they don’t show an actual constructed system, but this is so simple you could toss it together quickly and see for yourself. This is a great lesson on how to get a simple touch sensor into your projects. This video appears to be one of a series of class visuals, and you can find several others on youtube under this account.

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STK200 Pocket Change Programmer

February 3, 2011 by Jake W 48 Comments

A common complaints of beginners to microcontroller programming is the availability of DIY tools that do not require a parallel port. Using not much more than a couple of 74xx series chips and some protoboard, [Rue] was able to create an AVR programmer for less than the cost of some chips it can program – giving parallel programmers a run for thier money. [Rue] used Linux treat the ubiquitous PATA/IDE port as a parallel port. By having avrdude treat the programmer as an Atmel STK200, [Rue] was able to upload a blinky program to his AVR microcontroller through ISP. If anybody can think of an even lower cost unconventional solution give us a shout.

Digital Measuring Tape

February 2, 2011 by Mike Szczys 17 Comments

You’ll never come up short with this measuring tape. That’s because there isn’t actually any tape in the device; it measures distance based on the rotation of a wheel. Roll it across the room and you’ll get an accurate measurement of the distance the little bugger traveled. Like the Etch-a-Sketch from Monday this uses the encoder wheel from a mouse as the input. The IR emitter and sensor from the ubiquitous peripheral find a new home on the PCB that hosts the PIC 16F819. It monitors the rotation, turns it into inches, then spits that number out on a 7 segment display. Handy, and cheap!

Printable Wax As PCB Etch Resist

January 31, 2011 by Mike Szczys 28 Comments

What if there were only two steps for making your own printed circuit board; print, etch? That’s what [Jeff Gough] has been working on and he presented the process in his talk at 27C3. In the first portion of the video after the break [Jeff] talks about various industrial PCB manufacturing processes in a depth you may not have heard before. We found it to be interesting but at about thirty minutes into the clip he begins the presentation of his modified printer. It’s an inkjet that can print wax onto copper clad board. The wax acts as a resist for chemical etchants, and provides very high resolution. He’s using a heavily modified print head, which brings to mind that diy piezo inkjet head which also has wax printing in its future plans. This certainly seems promising and if the process can be simplified it might do away with the toner transfer method.

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Make Presents: The Multimeter

January 26, 2011 by Caleb Kraft 17 Comments

This video falls under the category of things we want to send people when they ask “how do I get started with electronics”, and we get asked that a lot. For those of you who have been working with electronics ~~for years~~ at all, you can skip this entire video. That is, unless you really want to watch an instructional video on multimeters. In the video, which we’ve included after the break, they talk about the differences between different meters, the common uses and how to actually use the meter to get the results you need. Stuffed full of useful information, this video will get those of you who are still reading up to snuff pretty quickly. Now go use your multimeter to do some hacking!

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Magnetic Digital Scale

January 21, 2011 by Mike Szczys 20 Comments

Above you see a solenoid being used as a digital scale. The magnetic field from the coil in the base levitates the platform above, where a load to be measured is place. This floating platform has a permanent magnet in it, hovering above a hall effect sensor in the base. As the distance between that magnet and the sensor changes, the measurable magnetic field changes as well. The hall effect sensor is linear so the measured value can easily be correlated with a weight. In the video after the break [Vsergeev] demonstrates the device using test weights to show off its 0.5 gram resolution. He thinks that with a few hardware improvements he could easily achieve 0.1g accuracy.

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Make Your Own Odometer From Scraps

January 19, 2011 by Greg R. Jacobs 11 Comments

For those out there who would enjoy a quick and interesting weekend project, this odometer made by [PeckLauros] is for you. Featured on Instructables it is made from the simplest of materials including some cardboard, a calculator, wires, glue, hot glue, magnetic drive key, an old CD and a reader, and a rubber band. The magnets, when attached to the CD work in a calculation to add 0.11m to the calculator when a magnet closes the circuit. [PeckLauros] points out that since it is a homebrewed device, it does have flaws such as adding 0.11m twice when the CD is rotated too slowly. It is easily fixed by simply running faster. The video is below the break.

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