You must have the PIC wired up & be
able to compile & load programs to do the other tutorials.
To run the other tutorials, follow these steps:
1. Connect circuit as described.
2. Compile the example code with whatever compiler you are
3. Load the program onto the PIC.
4. Turn on the power to run the program
If you don’t know how to code something, look at old PIC code on
the robotics lab’s computers. I have found that we need to solve
similar programming problems year after year, especially when we
are talking about sensor input & motor output. Chances are good
that somebody already wrote it. The PIC MCU C compiler manual is
a good reference too.
I recommend that you try to be neat when attaching wires & other
components. Cut your wires so that they lie flat on the
breadboard, not sticking up. Make sure the bare ends are long
enough to make a solid connection with the breadboard – you
don’t want a loose wire! Be orderly when you run wires to the
various sensors & motors, too. You will have a confusing
spaghetti forest when you add sensors, motors, switches, and
Another good idea
is to use wire colors consistently. For example, every time you
have a wire going to ground, use the same color, usually black.
That way, you can understand what it does with a glance. This is
important when you have 50+ wires on the board. I use red for
power (the + on the battery & breadboard), black for ground (the
-), blue for inputs, and green for outputs.
Always double check your
connections before flicking the switch. If just one wire is in
the wrong position, it could disable your circuit or burn
You can build your circuit with
test LEDs, to make sure it is working when you turn it on. I
have a power light directly connected to the battery to so I
know when the circuit is on. I also have an LED controlled by
the PIC. In my programs, I make the PIC turn the LED on when it
starts running. That way I know that the PIC is working
The Anode of the LED goes to the
+5v rail out of the regulator. The cathode of the LED goes to a
current limiting resistor – any value between 220 and 1k is
fine. The other end of the resistor goes to Ground. This LED
should turn on at full brightness when the circuit is turned on.
If the LED does not turn on, you may have the LED in backwards.
If you know the LED is in correctly, and it does not turn on or
turns on dimly when the power is turned on, TURN OFF YOUR
CIRCUIT, and check your wiring. This most likely means there is
a short somewhere with your power rails.
If you have been running the
robot for a while, check the power battery voltage. If the
voltage gets too low, the robot will behave strangely due to PIC
doing a “brownout”.