Let's Make Robots!


Line Following Sensors

Hello everyone,

I am making a line following robot for a competition in Australia called "Robocup Junior". It involves following a line, also, taking shortucts indicated by a green square. At the suggestion of one of the friendly LMRians I invested in an IR Sensor board that can follow the line perfectly. The only problem I have been having is that white and green have the same readings (must be a problem with infra-RED and GREEN being different, or something:)

So I am creating this thread to see if anyone has had any experience with any light or colour (color) sensors.

QRD1114 Resistor Values

Hi all,

I'm using a QRD1114 sensor for a line-follower. Datasheet: http://www.fairchildsemi.com/ds/QR/QRD1114.pdf

Im hooking it up with this schematic:

However, I'm unsure how the value for the 10K resistor was calculated? It's acting as a potential divider, right?

For the LED im guessing that the value of 220 was taken from doing:

R=(Input Voltage - Max Forward Voltage)/(Optimum forward current)