How does brain box of a car work?

Answer 1

Car Brain Boxes are electronic devices that incorporates microprocessors for the monitoring and control of various functions in a vehicle.

The brain boxes in most cases are specialized devices focusing on controlling multiple functions in a vehicle e.g. cruise control, automatic gear shifting, climate control, engine running, Fuel injection / emission control, collision avoidance, Powered mirror, seat & rear mirror controls etc.

These are usually custom built for different car manufacturing companies and are usually multi-purpose.

An electronic enthusiast can usually develop some simple brain box controllers for his/her car using PIC Microcontrollers for functions they desire to have in their vehicles but which did not come packaged with it.

I developed a small module for my car that automatically winds up the car windows, locks the doors after 30 minutes of shutting down the engine and closing all doors. The controller also doubles as a security system that taps into the cars injector firing system which cleverly avoids the normal areas car robbers would look into to disable car security system.

A brain box is usually much more complex than this, doing lots of complex calculations and taking complicated decisions to run the vehicle maximally.

Sogunro Elvis. esogunro@Yahoo.com

Someone emailed this question: How do I go about building one?

You need the following:

1. A very good understanding of your vehicles' wiring system

2. Depending on what you want to do, you may also need to have very good understanding of the principles behind the function you want to control.

3. If your brainbox is already controlling the function, it's advisable not to do any parallel control of this function, one or both controllers will malfunction.

4. If your brainbox is already taking input from any sensor which you also need as input, ensure the way you pick this input would not affect the signal level to the brainbox.

5. If you're sending out an output, ensure it does not go into an input or output pin of your brain box.

6. Generally, I'd adviceyou steer clear of your car's existing brainbox to avoid damage to your car.

7. If you must add a functionality to your car, then go about it as follows:

a. First put your thoughts down as they come, note down every little thing that comes to mind.

b. Arrange these thoughts in a logical manner and then draw a flowchart or a state machine diagram of the function you want, to represent this thinking, starting from the inputs to the desired output.

c. Select the PIC microcontroller that fits your design in terms of - no of inputs & output pins required, size & types of memory, number of ADCs, Timers, etc.

d. Draw up your schematic and identify / calculate the sizes of all the components required.

e. Set up a prototyping board for your chip where you can both code and simulate. (use switches, variable resistors etc to simulate inputs and motors, LEDs, etc to simulate outputs).

f. Develop code (a little at a time), download and test run, debug errors, re-code and test-run again until ok. I discovered it's usually easier to break your project into several small sections which makes coding easy.

g. Move to the next stage of coding, until you've completed everything.

h. Depending on your experience, you may need to read a lot, pick up coding tricks frrom the internet or friends, learn how to use interrupts and subroutines etc to simplify your work.

I. Keep It Simple.

j. When you believe you have a working version, take it to your car and connect "live". Do not forget to regulate the car's 12v down to the microcontrollers voltage otherwise you burn the controller.

k. Do a test run in the live environment, notice assumptions made that failed and other corrections needed. Go back and re-work as appropriate.

l. Design and print a PCB. Transfer the whole circuit onto this.

m. Design a packaging material to enclose and protect your circuit.

n. Install and commission (Fine tune)

o. Enjoy the fruit of your labour!