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You want a simple Photovore? This very tidy design by Solarbotics' own Grant McKee is based on a technique developed by Mark Tilden - Shok architecture:
Here's video of the test robots being tuned as a 177kB Windows Media Format (WMV) file or as a 168kB RealMedia (RM) file.
ShokPopper V1.0 (click for circuit diagram) - GrantM Aug 2001
Theory of operation:
"Shok" architecture is a technique pioneered by Mark Tilden describing controlled state changes of Bicore style circuits via chip power or enable toggling. When a Bicore circuit is powered on, it will resume a state opposite to what it was when it was powered off, this effect can either be duplicated by pulsing the enable line or by pulsing power to the chip itself. This is called "shoking" the Bicore. The power-on state can also be pre-determined by biasing the voltage across the Bicore capacitors. A photodiode attached directly across the Bicore charge capacitor will pre-bias the shoked output. The addition of tactile sensors is easily implemented by attaching a switch from the input of the Bicore to +Vdd. When the switch is closed, it forces that side high, presetting the state of the Bicore on the next pulse cycle.
Probably one of the simplest photovore circuits to date, the core circuit consists of a 6 part count and a solar-engine. Either 74AC240 or 74HCT240 will work but we recommend using the AC series for better output drive current. The ShokPopper will not work under battery power unless the enable line is pulsed.
Solar Engine to use with Shok:
The best solar-engine to use is the Miller engine. For the ShokPopper Photovore we used a Miller engine consisting of:
The Bicore Circuit Consists of:
The Miller engine switches the ground line of the circuit.
The theory of operating is very similar to that of the shok popper except that the head now only uses one motor, the photo head does not "lock" on but will continually seek for the brightest source of light. Nice effect if you want a continually seeking, dynamic device on a stationary base.
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Solarbotics held a few workshops and lectures at the MAKEr faire April 22/23rd. After giving a workshop, a nice man from Microsoft invited me over to see their BEAM robots. Obviously intregued, I found their display at the Microsoft pavilion where Microsoft encouraged all their engineers with "MAKE"-style hobbies to exhibit, including this squad of […]
Just a quick note to remind everyone that we are closed on Remembrance Day - Wednesday November 11 2015, and will resume responding to phone calls and emails the next day.
Wednesday naturally turns into Thursday, so the links seamlessly migrated from Wednesday to Thursday too... They are not allowed to Friday though, otherwise they will turn into pumpkins. Er, I mean Friday-not-so-cool links. Which will be just unacceptable! Hello World. A sign built from 5,000 rocker switches. An enormous grid made of 5,000 orange rocker […]
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