optical sensor

[archiver]

Posted by Lloyd Burns at 03/27/2001 4:58 PM EST


Engineer on team #188, Woburn Robotics, from Woburn Collegiate and TorDistSchoolBrd, ScotiaBank. OntPwrGen, Enbridge.


In Reply to: optical sensor
Posted by joe frick on 03/27/2001 12:14 PM EST:



: could anyone help me with the optical sensor?
: i want to use it as a limit switch how do i hook it up to digital imputs to control PWM 3

' see the connection diagram on the case, and the listing of the pinouts in the Innovation First manual.
One of the wires goes to ground, one to the +5 V pin, and one (of the two outputs) to the signal pin. One of the outputs is closed normally, but opens when it detects reflection; the other output closes at the same time. Closed to ground = 1 in the program.

: what i need is something that lets me start a match in a down position but prevent our robot from returning to this position during a match, so the switch would have to allow our robot to go up but not down. any help wou;ld be appreciated

' if rc_sw# = 1 then PWM3 = 0 (or 254 depending on how you've wired the motor.) This could compress into
PWM3 = 127 + rc_sw# * 127 (if 254 is up, or use - to get to 0).
' you could implement another limit switch or a timer / counter to make sure the part rose far enough, if your sensor is positioned to sense only the start.