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A project log for Cheap & Easy Digital Readout

A project to enable DIY high-resolution digital readouts inexpensively

Mike LowndsMike Lownds 08/19/2014 at 22:430 Comments

The scales will be made on black and white film stock. A pattern will be printed with a standard consumer printer and then photographed to miniaturize it onto the film.

The readers will be made from a pair of infrared photodiodes and an infrared LED. As the codestrip passes between the LED and photodiode it will block the light and create a changing voltage over the photodiode. We will use two photodiodes and monitor those voltage changes to track the position of the read head on the strip.

The control box and software will consist of a microcontroller to accept the photodiode input and do basic conversion from encoder counts to distance and basic machine safety functions. However, unlike similar commercial offerings, the control box will not have a display, or in fact any inputs or outputs save for a network connection. This connectivity will allow very flexible and feature-rich front ends to be created for the system and run on almost any bit of display hardware possible - from a laptop to a tablet or even a phone. And because the data is being processed by a powerful phone, tablet or laptop processor we will be able to do computationally expensive things that are simply not possible on a microprocessor, such as shape inspection using a probe, lathe workpiece runout inspection and quick vise alignment.

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