Dave Mawdsley, DACS Member, Linux SIG January 16, 2013 Using the DFRduino RoMeo Microcontroller with the DFRobot Mobile Platform (using an Arduino microcontroller with a 4-wheel robot) Dave Mawdsley, DACS Member, Linux SIG January 16, 2013

A Look Back: The Arduino Uno 1 A Look Back: The Arduino Uno

2 The DFRduino RoMeo v1.1

The DFRduino RoMeo v1.1 Diagram 3

Comparison Notes: Arduino Uno & DFRduino RoMeo v1.1 4 Comparison Notes: Arduino Uno & DFRduino RoMeo v1.1 The Arduino Uno is the gold standard of the Arduino series. It has functions expected of a microcontroller such as digital and analog I/O and easy connections to circuit boards and other devices. The DFRduino RoMeo v1.1 has the standard Arduino Uno features plus connections for two motor controls along with a set of digital and analog I/O pins for them. It also has 5 push button switches and a section for Bluetooth controls. The same IDE is used for both microcontrollers and when connecting up with the DFRduino RoMeo, the Arduino Uno is the board to choose in the setup. Power constraints are similar. The C language code used has extensions for motor controls and the like. Uploading code and running it uses the same procedures.

The DFRobot Pirate Mobile Platform 5 The DFRobot Pirate Mobile Platform

The Wheel and Frame Assembly 6 The Wheel and Frame Assembly

Wiring Between the Wheels & DFRduino 7 Wiring Between the Wheels & DFRduino

8 9 VDC Battery Details

Top Panel - Mounted DFRduino RoMeo 9 Top Panel - Mounted DFRduino RoMeo

Bottom Panel – Motor Battery Container 10 Bottom Panel – Motor Battery Container

Mostly Completed Hardware 11 Mostly Completed Hardware

The Completed Robot with Batteries 12 The Completed Robot with Batteries

A Side View of the Completed Robot 13 A Side View of the Completed Robot

Robot Direction Controls (lines 1-35) 14 Robot Direction Controls (lines 1-35)

Robot Direction Controls (lines 36-62) 15 Robot Direction Controls (lines 36-62)

Robot Direction Controls (lines 62-85) 16 Robot Direction Controls (lines 62-85)

Forward, Backward, Left, Right & Stop 17 Forward, Backward, Left, Right & Stop Wheels on the left side rotate the same way. Similarly with the right side of the robot. That is, on one side the wheels rotate forward or backward together. Rotation of the wheels on the left or right sides are independent, which makes for left and right turns with slippage. Wheels rotate faster on the right side to make a left turn. Turning right uses the opposite pattern. The program shown doesn't make for variable speeds, but the speeds can be adjusted based on the numbers 0 through 255 with the greater speed with the greater number. In the reverse direction the motor controls must reverse HIGH and LOW for both sets of wheels.

Important Power Issues 18 Important Power Issues The robot vehicle has two power sources: 7.5 VDC for the motors and 9 VDC for the DFRduino Romeo controller which requires 5 VDC to operate but which is insufficient to work motors as well. A USB cable supplies only 5 VDC to allow loading the object code. The 7.5 VDC consists of five 1.5 VDC AA batteries in series. This source must be plugged in and active before the DFRduino Romeo controller is powered on since the controller itself cannot power the 4 motors. I installed two power switches to allow for this sequence. The DFRduino Romeo controller should be the last to power on and the first to power off. It uses the 9 VDC to power the controller independent of cables and perhaps some other breadboard wiring. The Power In Selection Jumper near the motor connections of the DFRduino controller must be removed to allow for external power to be supplied to the wheels. Otherwise with the jumper, the DFRduino will try to power them.

Using the DFRduino RoMeo Microcontroller with the DFRobot Mobile Platform (using an Arduino microcontroller with a 4-wheel robot) This LibreOffice.org Presentation 'dfrduino.odp' can be downloaded from http://madmod.com/freebies.html