Photo IC Support
The SuperDroid Trekker uses the Photo IC sensor to detect a ball. Soccer robots are also gaining popularity. The object of the soccer robots is to work as a team and push a soccer ball towards a goal. This is a very complex and competitive sport. The Trekker can be equipped with brackets that attach to the front bumper switch. The brackets will detect if it has caught a ball using a IR sensor that shoots across the front of the bumper switch. The soccer robot works best with a Trekker that has a front scanner attached to the bumper switch and at least one sweeping scanner attached to the top of the Trekker on a scanner bracket. The basic principle of finding the ball is to use the top scanner and scanner attached to the bumper switch. If the lower sensor sees something the top scanner does not see, then it’s likely a ball. The top scanner will not see the ball since it is below its field of view. The Robot can then drive towards the ball, fetch it, and drive it to its goal.
The Trekker slowly scans the area with IR to detect objects.  When a change in the IR reading occurs, the OOPic "pings" the ultrasonic sensor and compares the two readings. If the readings vary by a value greater than the threshold set, the Trekker will move toward the object.  The Ultrasonic should not be able to see the ball since the ball is lower than its field of view. See figure below.
Ball Catcher Concept
If during that time the variance changes to a value less than the threshold, the Trekker aborts its "capture" attempt and continues scanning. Â When the Trekker does acquire a target, the IR emitter and collector beam located in the "catcher" will be broken by the object, thereby resetting the operation. Â When the object is removed from the "catcher" the Trekker will resume the search for objects.Â
Currently the Trekker will only operate in areas where the maximum distance from a ball is approximately 48".  It will work with any ball that is about the size of a tennis ball or slightly larger. The larger ball will be seen by the ultrasonic sensor.
Mechanical and Electrical Assembly
- 1. Wire the IR Emitter as shown in Figure below. All wire connections should be soldered.
- 2. The long lead goes to the red wire.
- 3. The Short lead goes to a 220-Ohm resistor, then to the black wire.
IR Emitter Wiring
- 4. Place heat shrink over the resistor and the lead
- 5. Place the larger heat shrink over the LED such that LED light will only emit forward. See Figure below.
IR Emitter Finished
- 6. Wire the IR Collector as shown in Figure below. All attachments should be soldered.
IR Collector Wiring
- 7. Place heat shrink over each lead. The finished collector should look like Figure below.
IR Collector Finished
- 8. Attach the red wire of the emitter to a ~38.5kHz PWM output and the black wire to the ground
- 9. Attach the red wire of the collector to 5V, the black wire to ground, and the yellow wire to a TTL digital input. The input of the collector will change state when the emitter is pointed towards the collector.
