Microcontroller Circuit Board & Complete Robot Electronics
This page shows the construction of a custom circuit board for the AVR microcontroller and
radio electronics shown previously, and the operation of all completed robot electronics together.
Here is a photo of the microcontroller on the breadboard:
Here is the proposed layout of the new circuit board:
Here is the completed circuit board with the ATMega16 chip installed:
Actually, this design is larger and more complicated than it needs to be, in that:
- I am using DIP and through-hole components rather than surface mount.
- I am using an external clock chip rather than the onboard oscillator.
- The board includes components for the radio, buttons, and 'heartbeat' LEDs.
- Although the current design uses only part of I/O port B (ISP programmer), port
C (LEDs, direction, feedback), and port D (radio, interrupts, PWM), I have brought all
other port pins out to headers. This makes the board a bit more generic, and allows
for future data acquisition (ADC input on port A) and other applications.
Here is a photo of everything hooked up and running on batteries:
The components include:
- The Bluetooth radio.
- The AVR microcontroller circuit board.
- Buttons for reset and 2 interrupts.
- 9V battery for radio and AVR.
- The motor controller circuit board.
- Two DC motors.
- Two optical switch feedback sensors.
- 12V batteries for motors.
Here is a very small (24 Mb!) movie of everything running (1:15). Click to download and play
(this may take a while).
The movie shows:
- The AVR running the default program, which just blinks the left LEDs on the right board. The top LED shows
that there is 5V power.
- After about 18 sec, the right LED comes on, indicating that the radio has received a
connection from the Mac.
- Then the top motor starts at 1/2 speed. Then the bottom motor starts at 1/2 speed.
Then the top motor goes to full speed. Then the top motor stops, and goes at 1/2 speed
in reverse, and then full speed. Then the bottom motor stops, and goes into reverse at full speed.
The next step is to build a housing for the circuit boards, and a chassis, wheels, and drivetrain for the
robot. Although this system is designed to run a 2 motor differential drive
rover, it can be the basis of any generic radio controlled 2 motor (or other PWM actuated device),
2 sensor robotic system.
İSky Coyote 2007