Back in the 80’s, there used to be a kid’s toy that would allow you to replicate an image by tracing a pre-drawn picture in one panel, while a mechanical arm laid down ink in another. We’d be hard-pressed to remember what the thing was called, but this Electrographic Enlarging Sketchifier would be a wonderful modern day stand-in.
flickr user [Imajilon] constructed this cool motorized pantograph out of tongue depressors, rivets, foam core board, and a handful of electronic components. Despite its bargain basement bill of materials, this thing is pretty darn cool. An optical sensor “views” an image and drives a simple FET circuit, replicating the picture automatically using an electrically driven pen mechanism.
Looking through her flickr stream, we thought the results were quite impressive. She does plan on making a second version of the Sketchifier with a smaller light sensitive area, which should allow her to resolve even smaller features of the source drawing.
[Dmitry Gr.] built a simple circuit to playback digital audio. At the center you can see an 8-pin PIC 12F1840 microcontroller. It’s pulling audio data from a microSD card which is read through a full-sized SD card adapter to which he soldered jumper wires for all of the necessary connections. There is one additional semiconductor, a FET which is used to drive the speaker seen to the left. Unregulated power is provided by a pair of AA batteries (four are seen in the picture above but only two are actually connected to the circuit). He’s planning to post his code package soon, but for now you’ll have to be satisfied with a couple of demo videos and a schematic. Both videos are embedded after the break, and we’ve also included a screenshot of the schematic which is shown in the second video.
This is very similar to the 1-Bit Symphony CD we saw almost a year ago in a links post. That one used a jewel case instead of the protoboard seen here, and had a headphone jack instead of the speaker.
Continue reading “Single-chip digital audio player”
If manufacturing printed circuit boards has become too easy you should try your hand at producing transistors. [Jeri Ellsworth] put together a collection of videos outlining the process. These go way beyond the IC fabrication we saw from her in the past. It doesn’t take much, a 1000 degree oven with steam option, silicone wafers, and a variety of chemicals. We’ve embedded the instructional video as well as two demonstrations of her N-style FET after the break. Continue reading “Transistor fabrication: so simple a child can do it”
[Jeri Ellsworth] is building her own pinball machine. Her build log is delivered in the form of daily videos that walk through the progress. In addition to seeing the intricate ramps, traps, and controllers she outlines her build techniques. These include reproducing parts based on old pinball machines and bending acrylic with a custom tool or a toaster oven.
The driver she’s planning to use is an Altera FPGA with a bunch of FETs to control the heavy-load components. There’s not a ton of info on the actual electronics but we had a heck of a fun time looking at the creative field components. Our favorite by far is the television from Day 7. The screen is translucent with a rear projected image. When the ramp in front of it is raised the pinball can be jumped right through the screen!
We couldn’t find a project page for this but we’ve embedded [Jeri’s] videos after the break. Continue reading “Pinball build throws down the gauntlet”
When I built my LumenLab projector, I used a thermal switch to run the fan. This simple control circuit looks like a nice alternative. The circuit is a simple adjustable temperature triggered Fet. If you know the resistance needed, you can replace the potentiometer with a cheap resistor. (You’ll want to use a DC fan)