King of Clever Reads 4-Pin Rotary Encoder with one Analog pin

Rotary encoders are pretty interesting pieces of technology. They’re a solid way to accurately measure rotation including the direction. [David] recently wrote some software to handle these input devices, but unlike everyone else, his application can get by on only one microcontroller pin.

Most people will use three pins to handle a rotary encoder with a microcontroller: one to handle the switch and two to handle the quadrature inputs. With only one pin left available on his project [David] had to look for another solution, and he focused on the principle that the encoder pins behaved in very specific ways when turning the shaft. He designed a circuit that generates an analog voltage based on the state of those pins. He also wrote a program that can recognize the new analog patterns produced by his rotary encoder and his new circuit.

If you’ve been stuck on a project that uses a rotary encoder because you’ve run out of pins, this novel approach may help you get un-stuck. It’s a pretty impressive feat of circuit design to boot. Just think of how many other projects use these types of input devices and could benefit from it!

[via Project Page go give it a Skull!]

Peculiar Radial Mill from Car Parts

Whether 3D printer, lasercutter, or mill, most CNC machines use human-friendly, square-angle Cartesian geometry. This intriguing concept mill instead uses radial axes where motion is derived from scrap Chevy flywheels. It may look and feel weird at first, but it works – sort of.

Cartesian axes are intuitive. If you want to go to the right, increase X. If you want to go to away from you, increase Y. If you want to lift, increase Z. On a manual mill this is easy for making rectangles and blocks, or, with creative clamping, straight lines of any sort. But if you want to carve a circle? As we all learned on an Etch-A-Sketch, you increase your swearing and then throw it in the corner.

HAD - Radial Mill2[Jason] knew that with a CNC machine all geometry problems are reduced to math done by software. With two offset discs, any position is possible by rotating both the correct way. It may look odd that both plates drunkenly meander about just to draw a straight line but the computer is ambivalent. Software can be complicated without penalty and is free once written – more on that later. If a machine is physically simple then it can be built and repaired easily and cheaply. This design does away with almost all the familiar – and [Jason] argues complicated – components of normal hobby CNC machines. No slides, rails, carriages or belts here. His design uses only about a dozen parts.

Because automotive flywheels are made from cast iron the machine is rigid and naturally dampening. Sticking with the junkyard theme he pulled bearings from an F-450 truck, good for a few thousand pounds. Some steppers and a Raspberry Pi and he was done – well, sort of.

[Jason] let us know that his project has sat for long enough that he has become passionate about other things and decided to move on. He documented his progress and submitted the tip in hope to inspire someone else to continue the design further. Any type of CNC is possible, not just a mill. 3D printer perhaps?

Two big caveats: it needs a Z-axis (linear, probably standard) and there appears to be deeper-seated-than-expected G-code demands to chit-chat about rectangles and only rectangles. Nothing insurmountable, just nothing he has solved yet himself.

[Jason] said not to expect any further updates from him but he would love to see what the next person could do with it.

See the video after the break of the mill drawing our skull and wrenches logo, (soft of, without a Z-axis to lift).

Continue reading “Peculiar Radial Mill from Car Parts”

DIY Super Accessory For Your Dremel

Little jobs require little tools and you can’t get much more littler than a Dremel. For his tiny tasks, [sdudley] has built a Dremel-powered base station that features a table saw, drum sander and router table. Overall, it is about one cubic foot in size and is almost entirely made from ‘1 by’ dimensional lumber. The Dremel power plant was actually used to make the base, specifically slowly removing material at the clamping points that hold the rotary tool secure to the base. The Dremel is held in an upright position and pokes out through the center of the table for both the drum sander and router configurations. To use this as a table saw, the Dremel is mounted almost horizontally on the base. A Mini Saw attachment has to be purchased for the table saw configuration but it does a great job at holding a vertically spinning saw blade.

After the break there’s a nice video of this tool’s use and assembly (it’s even worth watching just for the musical accompaniment that takes you on a wild ride through several genres of music). For those who want to make one for themselves, [sdudley] has made his part templates and assembly guide available in PDF format on his Instructables page. If you’re looking for something a little larger, check out this circular saw converted to a table saw.

Continue reading “DIY Super Accessory For Your Dremel”

Rotary Wall Plug from Scrap

Rotary tools such as a Dremel are useful to have around for all sorts of tasks in a workshop, including cutting, polishing, and grinding. [Konstantin] sent us in his home made wall mount rotary tool based off of parts from a blender and an old bench top jigsaw. Unlike a Dremel where the motor is in the hand held part of the tool, this setup hides the blender motor (which provides the power) behind a wall panel, and is controlled via the blender’s speed settings buttons. We could see this configuration allowing for more delicate work due to the reduction of weight in hand, as well as the added bonus of a near impossibility of losing this tool. Overall an excellent re-purposing of leftover parts, be sure to check out [Konstantin]’s blog for more build info and photos.

Rotary display uses VCR head and LEDs

[Daniel Daigle] is developing a rotary display that uses persistence of vision to graph data. The hardware he used includes a spinning head from a VCR, some LEDs, and a timing circuit to display 360 degrees of data. His timing input uses a waveform so this will work with any application where you can generate a PWM signal.

Check out his videos after the break that demonstrate a graph with a single line and another with six display lines.

Continue reading “Rotary display uses VCR head and LEDs”

Lower productivity by using a rotary num pad

[Maximilian Ernestus] sent us a quick little demo that shows him using a rotary phone dial as a num pad. We’re often frustrated when notebooks and netbooks prohibit us from using our mad 10-key skills (alternate key mapping doesn’t count). This makes coding and using GnuCash undesirable on small form factor portables.

Instead of fixing the problem, [Maximilian] made it worse by interfacing a rotary phone as a num pad. An Arduino counts the pulses and feeds them to the computer via a serial connection.  From there it’s just a bit of software handling to issue a keypress.  He mentions that a future version should register as a USB keyboard. This is a great opportunity to ditch the Arduino and use the V-USB library.

Want to dig a bit deeper into this old technology? Don’t miss out on the information available from the Magic Phone hack.

Rotary encoding with your soundcard

[Stefan] sent in this project writeup to show us how he used a stepper motor as a rotary encoder. Using a stepper motor as an encoder isn’t really that new, as [Stefan] points out, we’ve seen it several times before. He wanted to use this in the quickest simplest way with his computer though. Instead of doing any decoding on a separate microprocessor, he’s connected the stepper directly to his sound card and written code to do the rest. You can download that code and see a video of some practical applications on his site.