On Mon, Sep 19, 2016 at 12:52:22AM -0600, James Burkart wrote: > Curious, why are you using an LED as a light sensor? I've done this a time or two, so I'll offer some input. First the seminal paper on th subject by Dietz et. al.: http://math.hws.edu/vaughn/cpsc/336/docs/led-sensor.pdf A search for iDropper LED will pull it up. The basic idea is to use an ultra cheap, already connected sensor for low speed bi-directional communication. I started investigating it when I had a timer based controller that needed to be irregularly reconfigured. The previous iteration had worn out its config button. It already had an indicator LED. With this setup, it could be configured by shining a bright light onto that indicator LED. A $1 LED flashlight worked great. The advantages are that it's cheap, it's touchless, and it offers a modicum of tamper prevention because there is no obvious buttons to mess with. The iDropper concept in the paper offers modulated communication for options such as LED smart keys. The point is that it uses what is likely going to be available as an indicator anyway. It's interesting that you can still use the incoming sensor even if you are using the LED as an output indicator. And the cost is exactly one extra I/O pin for reverse biasing the LED. Hope this gives you some insight... BAJ >=20 > -- > Sincerely, >=20 > James Burkart > *Filmmaker & Documentarian* >=20 > *Burkart Studios* > 415.738.2071 | Phone > 925.226.4910 | Fax >=20 > *Web:* burkartstudios.com > *Facebook:* facebook.com/burkartstudios >=20 > On Mon, Sep 19, 2016 at 12:37 AM, wrote: >=20 > > Try a shielded wire where the shield is connected to the case. > > > > /Ruben > > > > On Sun, 18 Sep 2016 09:17:05 -0400, Gordon Williams > > wrote: > > > Hmm, because the wires are tightly twisted wouldn't any noise be > > > cancelled out? > > > > > > When I touch the case and wires the count goes back to what it is > > > without me touching the wires. > > > > > > Gordon > > > > > > > -- > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > > View/change your membership options at > > http://mailman.mit.edu/mailman/listinfo/piclist > > > --=20 > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 Byron A. Jeff Associate Professor: Department of Computer Science and Information Technol= ogy College of Information and Mathematical Sciences Clayton State University http://faculty.clayton.edu/bjeff --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .