Programmable Scientific Calculator Watch

January 19, 2009 by Nick Caiello 17 Comments

When the band support on [David]’s Casio CFX-400 Scientific Calculator Watch finally broke after 10 years of use, he found it almost impossible to find another watch with the same functionality. Like any good engineer, [David] decided to design a watch to meet his needs. The result of his endeavors was the µWatch, a programmable watch based on a PIC24 with both RPN and Algebraic calculation modes. The watch runs open source software and is expandable thanks to a serial port, an ICSP programming port, and a spot for an infrared LED on the board. On his site, [David] shows how he made the first µWatch and offers kits for anyone who wants to build their own. We’ve been told that the next batch of kits will be made available in 1-2 weeks and are expected to sell out fast.

[Thanks Tomesz]

High Frequency Start Box

January 19, 2009 by Caleb Kraft 52 Comments

start_box

When welding with an AC arc welder, it is often necessary to “scratch start” them to get the arc going. For those unfamiliar, it is just like it sounds. You drag the head across something just like a giant match. There are some that come with an arc stabilizer or “high frequency starter”. This is preferred, but they can be hard to find. [Bill] shows us how to make one of our own. Though you may have an easy enough time finding a big transformer, you might run into some difficulty finding the capacitors, and tungsten spark gaps. If you manage to get your hands on them, you can follow [Bill]’s schematic and build one of these starters for yourself.

ATtiny Breadboard Headers

January 18, 2009 by Eliot 22 Comments

attiny

[Alex] was frustrated by the amount of time it took to start prototyping with an AVR ATtiny. To make things easier, he built headers that carry the 8 and 20 pin chips and plug directly into breadboards. The boards include a 6pin ISP header, resonator, pull-up resistor, reset, and blocking caps. The ATtiny2313 version also has a serial connection header. This is a prototype though, and he forgot to route one of the connections. He plans on having a large batch of boards ready for next month.

RepRap Pinch Wheel Extruder

January 17, 2009 by Eliot 3 Comments

pinchwheel

What you see above is the culmination of [Zach Smith]’s work building a pinch wheel style extruder for the RepRap. The current RepRap 3D printer uses a screw mechanism to push 3mm polymer filament into a heating barrel where it is melted and then extruded through a fine nozzle. [Zach]’s new version uses a drive gear from SDP/SI mounted directly to the DC motor we saw him teardown earlier. He’s redesigned the carrier for the extruder as well. It’s now much lighter and has provisions for mounting current and future controller electronics along with a magnetic rotary encoder. In the last two days, he’s been doing real world testing. It’s been doing well, but he’s learning to do things like always using a full spool and not trying to run short lengths back to back.

PID SMD Reflow Hot Plate

January 16, 2009 by Eliot 15 Comments

[mightyohm] put together a nice piece of lab kit. It’s a PID controlled hot plate. The plate is capable of reaching 500F, hot enough to do SMD reflow soldering. The large chunk of metal has a hole drilled through the center to contain a cartridge heater. A thermocouple is used to monitor the temperature of the plate. Ceramic standoffs separate the plate from the rest of the device, but he still needs to come up with a way to stop the radiant heating. The control box houses the surplus PID controller along with the power switch and solid state relay (SSR).

Tape Measure Generator

January 15, 2009 by Caleb Kraft 39 Comments

generator

[Dr. West] wanted to do his small part to help save the planet. He has built a small generator from a stepper motor and a tape measure. The tape part of the tape measure was replaced with some cord. The spring loading mechanism makes the string re-wind automatically, which is nice. He shows it attached to one leg, with the string tied to the other, generating power while he walks. This is cumbersome, but seems fairly effective. You can see him waking around in a video after the break. Would this benefit from a flywheel or friction drive to keep the motor spinning after each pull? How can he rig it to feed off of the motion of only one leg to avoid tripping hazards?

Continue reading “Tape Measure Generator” →

Oomlout’s Guide To Kitting

January 14, 2009 by Eliot 14 Comments

oomlout

The team at oomlout has continued to post all the methods they use in their manufacturing process. This time around it’s the kitting process: how they actually packaged 30 identical SERB kits in an efficient fashion. We covered their wire cutting bot before, but they’ve got other dedicated machines like a sticker cutter. The stickers are used to remove all the cut acrylic pieces from the laser cutter as one unit. They’ve got some other tricks like using a scale to count bolt quantities, and an egg timer to keep track of the laser cutting. All of their envelopes are printed using a parallel port inkjet that has been modified to work with any thickness paper.

We love when hackers bother to post this much detail about their process. One of our favorites is [ladyada]’s full rundown of how the Minty Boost was created.