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This custom PCB, with a design also suitable for a 4WD mecanum robot, is now at a 'ready to use' design stage, and shown above are the front and back images from the KiCAD software for the 4^th version of the design.

The design aims for this PCB are to:

• allow it to connect to any of the Raspberry Pi SBCs, although primarily focused on a Raspberry Pi 4 ;
• to have either simple onboard jumper headers or more usefully slide switches that can be used to 'set' the logical on/off and operation mode of the robot;
• to provide direct interface connections for:
  • two I²C connections - one to be use for the standard 128x64 pixel OLED;
  • a PCA9685 servo control module - not generally used but potentailly useful for future builds with multiple servos;
  • one simple/direct servo connection - to be used for the standard SG90 'scanning' servo;
  • a 4-pin interface for an ultrasonic sensor (3V3 only!) - to be used for the standard HC-SR04P sensor component;
  • two simple 2-pin interfaces for 'bump' switches - not used in the initial build but enables the addition of bump sensors;
  • a 3-pin interface for a PIR/microwave sensor input - not used in the initial build but enables the use of an additional microwave radar object sensor; and
  • 2 sets of 6 GPIO pins for controlling a pair of L298N motor controllers - therefore enabling independent control of four individual wheels.
• a single colour LED and passive buzzer is also directly connected to the PCB - used as a robot status indicator; and
• a power bus provided with microUSB and JST connectors and a jumper connection so that both the system controller and any connected devices can be powered from a single source such as a 5V rechargeable 'power bank'.

 

 

Current custom PCB designs:

 

 

All the detailed Flexible Hardware Design web pages:

 

 

Robotics projects:

 

 

All the currently available maker project information: