Car - olonho/carkot GitHub Wiki
Car platform: DFRobot Pirate 4wd. It includes body, wheels, engines, reduction drives.
Motor drivers: ST L293D
Controlling MCU board: STM32F407G-DISC1
Now we'll look at different parts of the car.
Assembled car frontal view.
1 - USB connector to PC. Use this to power the board from PC/flash MCU/debug MCU.
2 - enable wheel engines power supply. Power supplies are common for MCU and motor driver IC but wheel engines have separate power supply because the require different voltage and high current.
Assembled car top view.
1 - MCU and engine driver IC power supply. It is usual USB charger for Phones/Tablets/etc. In order to power up the car you need to connect 2 usb charger wires to MCU board 5V and GND pins. I haven't checked but it is probably ok to connect the charger to PC USB port (2) too.
2 - USB port for connecting to PC. Use it to power up MCU, debug, flash it.
3 - SB10 solder bridge connectors. Connect them when you power up MCU from (1). Disconnect when you power up MCU from PC. This is needed because when MCU board debug processor doesn't power up MCU until it finds some intelligent USB host connected on (2). If we connect this two connectors then we disable board debug processor. Look here for details: http://electronics.stackexchange.com/questions/236040/external-power-to-stm32f4-discovery-board
4 - Car engine control connector. This wire connects MCU GPIOs with engine driver IC input pins. So this wire delivers MCU logical commands to engines. Look into car_fmw/src/car_engine.h to find out semantic of signals on each connected GPIO pin.
5 - Car engine driver IC power supply connector. This IC needs 5V that we get from MCU board.
Car top-side view with removed MCU board platform.
1 - Car engines power supply connector. It is connected to motor driver that delivers it to engines when engines control logic signal tells motor driver to run engines.
2 - Controlled car engines power supply connectors. Power is supplied on this wires only when engines should be running. Left and right pairs of wheel engines have dedicated controlled power supply wires because each pair should be controlled separately. For example when we turn right we need to rotate left wheels pair forward and right wheels pair backward.
3 - Engine driver IC power supply. This one supplies driver IC logic and doesn't interconnect with engines power supply. Connect other side of this wire to 5V and GND pins of MCU board.
4 - Car engine control connector. See its purpose in the previous section. This should be connected to right inputs of engine driver IC. Engine driver IC has two channels each one controls one pair of wheels (left or right). You can find info about engine and engine driver commutation on dedicated wiki page.
5 - Engine driver. This accepts low current logical signals from MCU GPIOs and converts them into high power signals for car engines.
Car top view with removed MCU board platform and removed engine driver breadboard platform.
This part of car contains 4 engines with reduction drives and 5 AA batteries used as power source for the engines. Voltage sum is 1.2-1.5 * 5. Up to ~2A current is used by the engines.
1 - Engines power supply wires. + wire should go into engine driver IC Vss pin. - wire should go to engine driver IC breadboard -.
2 - Left wheels engines pair power supply wires. They should be connected to engine driver IC output pins related to left wheels pair.
2 - Right wheels engines pair power supply wires. They should be connected to engine driver IC output pins related to right wheels pair.