4tronix Picon Plus
Les Pounder needs to build a robot to help during social isolation. But can he build a robot butler to deliver more Pis to his table?
Les Pounder needs to build a robot to help during social isolation. But can he build a robot butler to deliver more Pis to his table?
Advanced robotics projects with the Raspberry Pi need a little more power than others. We need bigger motors, and more of them. We need servos to control steering and inputs to simplify sensors such as ultrasonic and IR. The 4tronix Picon Plus fills this void and offers a little extra for £30.
Designed for the HAT standard and compatible with all recent models of Raspberry Pi, Picon Plus occupies all 40 pins of the GPIO but it only uses four pins, I2C and power pins. This leaves the rest of the pins available for general use. To access the pins an extension header is required. More Picon Plus boards can be added on top of each other for a total of four boards and 16 motors! Each of the Picon Plus boards can be controlled independently thanks to the I2C interface and their unique identifiers.
Picon Plus provides four inputs and four outputs which offer SVG, Signal, Voltage and Ground for use with compatible devices such as servo motors. Inputs can be used with sensors or simple buttons depending on your needs. The device has screw terminals along one side of the board. Four of the screw terminal outputs are for use with up to four motors, all at once. This means we can build four-wheel drive robots, and because each motor can have their output adjusted using PWM (pulse width modulation) it gives us individual power control. Using four IFX9201 H-bridge motor controllers, each rated for up to 6A of current, we can use heavy-duty motors in our builds.
Power for the motors is provided via a DC barrel jack or via a screw terminal and we can supply up to 25V of DC power, which is regulated down to 5V, 3A to power the Raspberry Pi via the GPIO and to power our motors.
To control our build we have a simple Python 3 library, and a series of example files that demonstrate how to use the various functions for motor and servo control. It’s great to see that 4tronix is now using Python 3 in its projects. Previously, it’s only provided Python 2 libraries and examples and this was something which we have commented on in previous reviews. The Picon Plus library is designed for ease of use. The level of abstraction is enough for new users to understand what a command may do, but also offers enough for advanced users to dig in a little further and tweak the library accordingly.
Greater flexibility
What makes this board a little different to most motor controllers is an ATMEGA328P-AU that handles communication between the Python library and the motor controllers. The ATMEGA328P-AU can be tweaked using the Arduino IDE via a micro USB port. So if you need to make adjustments to how the board works with your project, you have the flexibility to alter the code and update the board using the Arduino IDE.
Picon Plus is simple to install, use and solves the problem of powering multiple high-current motors. The single power source and battery monitoring is superb and provides a tidy means to power the Raspberry Pi and the robot. It does everything so well and easily, for a very reasonable £30. The friction, the issues that we discover when building a robot are lessened with good hardware and software, and here we have both!
If you need a motor controller and are already well versed with Python and robotics, then Picon Plus is the ideal board with which to build a new project.