Controls

To make the robot free of human intervention (because it is intended to operate in radiation contaminated areas) the height adjustment of the alpha particle sensors needs to be autonomous. Several solutions exist for this task but our team decided to utilize the Arduino that was provided to us by professor Deshpande. The Arduino needed eyes to see if there were object on the ground or changes in terrain to adjust the height of the alpha particle sensors. We chose the Sharp Infrared Proximity Sensor shown in the figure below. This infrared sensor returns a value between 0.5-4.5V depending on the distance of the object placed in front of it.

We calibrated the sensor by placing it on a table and placing a wooden block in front of it. We recorded the value read by the Arduino and then moved the block in one inch increments. The curve of this data is shown below.

After doing that curve fit, we could relate an analog value to a distance. We could then write our code to adjust the height of the alpha particle sensor. This was done by demanding an angle from the servo motor which yielded a certain vertical position for the alpha particle sensor. The output angle is generated by a high torque servo motor. With this feedback system, we were able to make the height adjustment autonomous.