Our goal was to create a wireless remote controlled car that was able to perform basic functions including going forwards, reverse, and turning left and right
The addition of a 3 Servo robotic arm attached to the car’s base was made and has the basic functionality of controlling the arm’s positioning and grip
The wireless controller consisted of two joysticks which were connected to an Arduino and a Xbee
The Xbee connected to the controller transmitted the user controlled joystick values to the receiving Xbee connected to the Mbed on board the car
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Software Used and Developed
Setting up the Wireless Transmitter and Receiver
The XBees had to be plugged into a PC and configured using a Sparkfun USB XBee adapter and the XCTU software from Digi International
The XBees are RF transceiver and receiver modules and therefore have to be configured to the same channel and have the same ID in order to broadcast and receive serial data
The arduino was programmed to send out the data to the XBee using Serial.write()
On Board Robot Controls
The two DC motors in charge of moving the car forwards, backwards, and turning were driven by a dual H-bridge whose inputs were connected to the mbed
The functions included in the mbed motor.h library were used to control the speed as well as turning
The servo driven robotic arm on board the car utilized the Servo.h mbed libraries
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Completed Wireless Controller
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Completed RC Car
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Summary of Results
In all, the build worked out the way we had planned and expected
We had an issue with the servo in the robot arm that was responsible for the claw grip
We were able to replace the servo, but the spare servo used did not fit within the claw and resulted in the grip strength being more or less useless when attempting to pick up items
As a result, our demo video displays the robot navigating and popping a balloon with a needle attached to the arm instead of the previously planned demo of it picking up an object
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Ideas for Further Work
Addition of obstacle avoidance protocol
Overrides the user’s controls when a sonar sensor detects an obstacle within a critical range
Return the control to the user once the robot has navigated away from the obstacle
Necessary for robot’s self preservation to make up for human error
Safety protocol for when the wireless controller disconnects from the robot
Interrupt routine shuts down the motors and sends a broadcast on the channel and awaits an ACK
Return the control to the user once the XBee on board has received an ACK from the controller
Necessary if the controller ends up out of range, has died, or if the channel is experiencing too much noise from surrounding devices