Old Chart Recorder becomes Single-Pixel Scanner

With so many ways to capture images from paper, do we really need another one? Especially one that takes 15 minutes to capture a 128×128 pixel image? Probably not, but building a single-pixel RGB scanner is pretty instructive, and good clean fun to boot.

We have to admit that when [Kerry Wong] scored an ancient Hewlett-Packard X-Y chart recorder a while back, we wondered if it would lead to anything useful. One may quibble with the claim that the Lorenz attractor plotter he built with it is useful, and this single pixel scanner is equally suspect, but we like the idea. Using an Arduino to drive the X- and X-axis of the recorder through a raster pattern over the bed and replacing the pen with an RGB sensor board, [Kerry] was able to collect the color data for each pixel and reconstruct the image. It wouldn’t be too hard to replicate this if you don’t have an analog X-Y recorder, which just goes to show that not everything needs to be steppers and digital to get something useful done. Or at least semi-useful.

As for the RGB sensor used, they’ve made appearances here many times before, mostly in M&M sorters but with the occasional synesthesia simulator.

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Smart Phone Camera Turns Laser Cutter into Hi-Res Scanner

Getting decent macro photos always seems to be a chore. Some important detail always seems to be just outside of the depth of field, or you have to be zoomed in so close that you get great detail in one spot but miss the big picture. [Nate B] had such a problem while trying to document some PC boards, and he came up with a nifty hack that uses a laser cutter and a smart phone camera to do the job.

Pv150a-front
Click for detail.

Having first tried scanning the boards with a flat-bed scanner but finding the depth of field unsatisfactory, [Nate B] then went on to his Samsung phone’s camera. Set to panorama mode, he manually scanned across the boards and let the camera stitch the images together. The results were better, but the wobblies got the better of him and the images showed it. He then decided to use a laser cutter — with the laser disabled, of course — as an impromptu X-Y stage to raster his camera above the boards. In a slightly cringe-worthy move, he gingerly clamped the phone to the cutter gantry, started the panorama, and let the cutter move over the board. This results in a rock-solid pictures of his boards with a lot of detail – perfect for his documentation. As a bonus, the honeycomb laser cutter bed makes for an interesting background texture.

Obviously anything could be used to raster a camera and achieve similar results, but full points here for maximizing available resources and not over-complicating a simple job. Yet another reason you can use to justify that laser-cutter purchase.

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Oscilloscope doubles as a serial terminal

PC-based USB oscilloscopes are fast becoming all the rage. [Matt Sarnoff’s] Terminalscope takes the reverse approach, adapting an oscilloscope into a full serial terminal. You may have seen something similar before in the Dutchtronix/SparkFun O-Clock, but [Matt’s] project goes one further by adding a PS/2 keyboard port for full bidirectional serial communication, and with much sharper display resolution to boot.

The mostly VT-100 compatible Terminalscope is built around two AVR microcontrollers: an ATmega328P runs full-tilt to generate the video signal and handle serial I/O, while an ATtiny45 handles keyboard input to avoid interrupting the ’328’s duties. Rather than vector trace each character, a raster-scanning approach is used: the beam follows a fixed X/Y path (like a television), while modulating the Z input (beam intensity) to form an image. The device can be connected to a PC via serial port or USB-to-TTY adapter, or directly to another microcontroller to debug serial output.

We recently showed an oscilloscope being used as a multichannel digital logic display. The Terminalscope provides yet another use for this essential bench tool and could nicely round out a “poor man’s” testing setup. The schematic and full source code are available for download.