Elf – 2WD Pi Robot
Building Elf
The Magician chassis comes with assembly diagrams, so I do not need to cover assembling the robot chassis in this article.
You need to solder a black wire, and a green wire, to each of the two motors. You can always change the direction at the screw terminals for each motor on the motor driver board.
The previous images show where I mounted my Robo Pi and Raspberry pi, you can of course mount them anywhere on the chassis that you like.
Before we can wire up the motor controller and ultrasonic range sensor, I will describe the RoboPi connectors we will use.
(click on image for larger version)
As you can see on the photo above, each of the servo pins has a corresponding current limiting resistor and a pin in a female socket in a straight line.
The sensor servo style pins had to be offset from their corresponding resistors and female pins due to the mounting hole needed for the Raspberry Pi, but are in the same order as the sensor pins.
Each of the ten pin sockets also has a GND (closest to the last resistor on the longer side of the header) and a 3v3 power pin (furthest from the current limiting resistor).
Servo Pin Functions
For Servo1 .. Servo8 svt2 selects between 5V and VBat for the VCC pin
For Servo9 .. Servo16 svt3 selects between 5V and VBat for the VCC pin
| For each Servo pin | Function |
| Female Header pin | 3.3V signal |
| Resistor | current limiter for 5v |
| Servo SIG pin | 5V input/output |
| Servo VCC pin | 5V/VBat power |
| Servo GND pin | Ground |
Sensor Pin Functions
For Sensor1 .. Sensor8 VCC is 5V (cannot use VBat)
| For each Sensor pin | Function |
| Female Header pin | 3.3V signal |
| Resistor | current limiter for 5v |
| Servo SIG pin | 5V input/output |
| Servo VCC pin | 5V power |
| Servo GND pin | Ground |
Analog Input pins
| Analog input pin | Function |
| Servo SIG pin | 0-5V analog input |
| Servo VCC pin | 5V power |
| Servo GND pin | Ground |
