1. Overview Hardware
For this project, additional hardware has been installed on the robot:
This infrared sensor is mounted at various positions on the robot, using a custom 3D printed socket and support. The sensors are distributed in a way that each faces a different direction (front, left, right, back).
When powered with 5 Volts each sensor delivers a non-linear analog Voltage level depending on its distance to an object (application range 10 - 80 cm).
This WiFi-enabled microcontroller reads the latest sensor voltage, transforms it into a corresponding distance value via inverse linearization and publishes the calculated distance as a sensor_msgs/Range ROS message using the rosserial-protocol. This is done for multiple connected sensors.
Since the robot does not have external power supply options along the arm, an external power supply for roughly 5 microcontrollers + 20 sensors was provided.
The schematic for a single sensor unit (microcontroller + adjacent sensors) looks as follows:
