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York Jong

Maxibug, Minibug, Microbug - 0 views

home.wanadoo.nl/...maxibug.htm

5star 74x14 beam circuit diy electronics maxibug photopopper phototrope photovore robot tutorial

shared by York Jong on 27 May 07 - Cached
  • It is powered with two 3.3F Goldcaps. They can be charged in a few seconds. When they are charged, MAXIBUg gets "afraid" of light, and wanders of to go to play "in the dark". After a while, about 20 seconds (depending on the current used by the two motors ), the power has dropped, and it wants to "eat". It gets light attracted, and will turn and go to the light. When it gets there, it will recharge and still will be atrackted to the light until it reaches a trigger voltage , at which it gets "afraid"of the light again. This will go on all day until someone turns off the lightsource. While doing all this it also will backup when bumping into something.
  • Because of the "on-off" output of the first schmitt trigger, the inputs for the LDRs will switch. That's why it gets light atracted -light afraid. This also means that you cannot use IR diodes (like SHF205). You have to use LDRs !
  • ...2 more annotations...
  • The change in output is visualised with two red LEDs. When the LEDs are burning, the bot is "afraid" of light. They are mounted as eyes off the bot, that's why I used two off them. One LED will do also, but doesn't look nice !
York Jong

74*240-based photopopper circuits - 0 views

library.solarbotics.net/...bot_popper_240.html

5star 74x240 beam circuit electronics maxibug photopopper phototrope robot

shared by York Jong on 27 May 07 - Cached
  • This adapted photodiode is not as sensitive as large area types so C2 may need to be reduced to 0.01uF while the value of R2 and R3 can be increased by a factor of 10.
  • Two leaded phototransistors can also be used but may require extra shielding to reduce light current in the bridge to acceptable levels
  • basic photopopper functions plus reverse -- all on a single chip
  • ...8 more annotations...
  • The monocore capacitor is for positive feedback for fast switching between the two motors and to slow down and avoid high frequency oscillations.
  • R2 together with C2 limits the maximum frequency of the monocore and motor drivers when the light is bright and the sensors are equally lit
  • R3 together with C2 sets the minimum frequency of the waggle even in the complete dark which is more interesting than twirling endlessly in a circle.
  • Having said that, maxibug is not perfect: it churns its wheels while feeding and does not back out of the feeding station when full. CD MaxiBug v5 uses just a few more parts but has powerful and efficient motor drivers, its motors are off while feeding, and it backs up when full.
  • The CD Maxibug v5 uses just one 74AC240 chip
York Jong

74*14-based photopopper circuits - 0 views

library.solarbotics.net/...bot_popper_14.html

5star 74x14 beam circuit electronics maxibug photopopper phototrope robot

shared by York Jong on 27 May 07 - Cached
  • Droidmakr (Cliff Boerema) came up with an interesting idea for a light-tracking head with a form of peripheral vision. As often happens, the circuit turned into something different -- a photopopper:
  • All done with a single 74HC14 (the '240 being a motor driver).
  • I tried the same setup with the 74*240 (with an extra inverter per motor) and 7404, but the 74HC14 seems to work best.
  • ...6 more annotations...
  • John-Isaac Mumford started off by simplifying the Maxibug design, and wound up with an entirely new circuit -- Mazibug
  • The tactiles switches behave even more strongly: if a switch is closed then the bot turns away unconditionally. If both switches are closed the robots reverse straight back regardless of light level.
  • When the robot bumps into something on one side, it over-rides all the photodiode circuits and reverses the motor on the OPPOSITE side
  • From the title it would appear that all 4 photodiodes face forward but the 2 inner PDs face directly forward and the outer 2 are angled to the left and right
    • York Jong
      York Jong on 03 Jun 07
       
      behavior-based control that all done with a sigle 74HC14
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