hello friends and keil men
I need your advice for starting a medium complexity project: a Digital Fuel Quantity Gauge. As you know, most older cars have a very rudimentary analog gauge, showing full (F), empty (E) and a warning light for low on fuel. They measure the voltage send by a sender unit, which is a variable resistor attached to a float inside fuel tank. NOTE: there are cars with senders having low resistance when tank is empty, and also other cars have the opposite.
My idea is this: design the simplest CORTEX circuit that is basically a non-linear digital voltmeter (due to irregular shape of fuel tank) and has the following specifications: - 4 buttons operated: UP, DOWN, SET, MODE. - calibration mode: specify up to 10 points of calibration - measuring mode: continuously interpolate between calibration points - gauge made using the smallest 7-segment LED displays (bi-color, 3 pieces showing 88.8 in liters) - temperature will be changed (blue if cold, yellow if warm, red if cold)
In calibration mode the user should start with an empty fuel tank. He then pushes the MODE button to enter in calibration mode (indicated by flashing the comma point), selects 00.0 using UP/DOWN buttons, then pushes the SET button to memorize 1st calibration point. In a similar manner, the user enters up to 10 points after pouring the respective fuel quantity in his fuel tank. At the end, he pushes the MODE button to switch to measuring mode.
As a finishing touch, the display digits should turn RED at a preselected low fuel quantity.
Please guide my approach, either by pointing ready made similar projects published in electronics magazines, or by giving me some tips from your experience.
Looking forward to hear from my friends.
Most people make a very serious effort not to allow the car to run dry before filling up!
It is a very bad idea to run a fuel-injection system (petrol or diesel) dry...