Hey guys, lately I have been working on the 555 photovore project. Doing my research, I came across a version that uses photodiodes instead of LDRs. This was my first design but I was talking to a veteran and I was told that this would only work with LDR's is this information accurate?
Sources:
- http://forum.allaboutcircuits.com/showthread.php?t=51695
- https://www.robotshop.com/letsmakerobots/node/33368 (include all comments ;) )
- http://www.instructables.com/answers/555-timer-photovore-light-seeking-robot-is-unbal/
- http://www.instructables.com/id/Simple-light-seeking-robot-with-555-timing-IC/
Thanks guys I appreciate it.
UPDATE: 12/9/2012: LDR's are the only thing that will work (Thanks AndroidMan ;) ) for this circuit unless drastic modifications are taken, at this point the 555 is no longer worth using, but an lm393 should be instituded instead if you wish to to use photodiodes. If you use the lm393, you must use transistors becuase the lm393 will not be able to provide enough current for motors. The moral of this story is use LDRs, they're cheap, they're easy to use and they WORK.
If you plan on using geared motors, I would recommend oddbot's circuit :)
Keep the comments coming :)