Virtual Wall Unit
The robot also uses its front IR emitter and sensor to aid its navigation. By processing the reflected IR beam from its own emitter, the robot is able perform tasks such as following along the side of a wall.
In addition, the onboard IR sensor interacts with "virtual wall" units to restrict the robot in the designated areas.
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Both the "virtual wall" and the robot features omnidirectional IR sensors. A parabolic lense collects and focuses the IR beam down to an upward facing phototransistor.
This signals a possible less invasive approach to control the robot. For example, by mounting additional IR emitters on the robot, we might be able to create "dynamic virtual walls" to steer the robot.
We also performed a power analysis on the "virtual wall" unit itself by connecting the unit to a HP E3631A power supply set to 3 Volts. The following table summarizes the power characteristics of the three range settings on the "virtual wall" unit.
| Setting | 0-3 | 4-7 | 8+ |
|---|---|---|---|
| Current | 25 mA | 42 mA | 160 mA |
The IR emissions is constant and non-pulsing. We made an ad hoc "virtual wall" unit by connecting a generic IR emittor to our programmable power supply. The robot responded to our contraption effectively.