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ab
12-17-2004, 01:02 PM
Hi, I am trying to build a micromouse, and I am using an IR LED modulated at 38 Khz and a TSOP1738 receiving set. I want to avoid using top-down sensors on the sides (for compactness). But the problem with using side-sensors (sensors fitted on the sides of the body) is that the LED being highly directional, a single LED-TSOP1738 set would fail if the mouse is not parallel to the walls. I guess I would need more than one receiver in this case; could any of you suggest ideas on how to build effective side sensors? (our calculated range is approximately 20 cm)

happy_99
12-17-2004, 10:26 PM
I've seen robots that use more than one IR LED for a single Photo Diode. I think it works in your case.

Regds

happy_99

Vivek
12-18-2004, 07:52 AM
usually its nice to have leds on both sides of the sensor.

If you really want the robot to be parallel to the walls, (which would help you gain higher speed),
keep 2 sensors on both sides.

Left front
Left back
Right front and
Right back
(all facing sideways, and +1 for forward face, +1 for rear face)

so the CPU logic would now try to keep the robot parallel when moving straight.
This would reduce the left-right swinging motion and hence increase forward speed.

cheers!

ab
12-19-2004, 11:20 AM
thanks for the help
i've read up on that too.. the problem we are facing is that we aren't getting a good range from it. the sensor detects the source upto a range of ~ 14 cms. our requirement is ~20 cms (with single reflection). our second problem is the directivity of the ir signal. ours provide about 15degrees(?) of directivity. it will probably not work if the bot is at an angle to the wall (since the distance between the bot and the wall is greater..)
i guess that'd mean using more IR leads for each position? any better ideas?
has anybody found a sharp GP2D120 (or similar voltage to distance converters) in india, jaipur or delhi?

thanks

happy_99
12-20-2004, 11:47 PM
thanks for the help

has anybody found a sharp GP2D120 (or similar voltage to distance converters) in india, jaipur or delhi?

thanks

I brought 2 pcs from Acroname USA. $23 for 2 sensors and $7 for shipping.

Regds

happy_99

ig
12-26-2004, 11:05 PM
try using tk1838, it's available in delhi markets.. that can greatly improve the range as well as the directivity issue.. it's available at rs 25 a piece.
tell me if it works out

cheers