Microlight Fuel Gauge

The design of this measuring instrument was based on thse requirements:
- a microlight always takes off with the fuel tank full; – fuel consumption is usually between 7 and 9 litres/hour; – it’s important for the gauge to be perfectly readable in all circumstances, e.g. in the form of a bargraph; – an indication of the amount of fuel remaining, expressed in litres;– an indication of the instantaneous fuel consumption (l/h); – it must be possible to have complete confidence in the gauge, so provision needs to be made for a warning in the event of it going wrong; All requirements are catered for by the present design.

Resistors
R1 = 1kOhm
R2 = 33Ohm
R3 = 4kOhm7
P1 = 10 kOhm preset
Capacitors
C1 = 220µF 25V
C2 = 10µF 25V
C3-C6 = 100nF
C7,C8 = 22pF
Semiconductors
D1 = 1N4004
D2 = LED, red
IC1 = 7805
IC2 = ATMEGA8, programmed with hex file from archive 080054-11.zip
Miscellaneous
X1 = 32.768 kHz quartz crystal
K1 = 2-way pinheader
K2 = 16-way SIL pinheader
K3 = 3-way pinheader
LCD, 2 x 16 characters with backlight, general purpose
F1 = flow meter, Digmesa type FHKSC 932-8501 (Conrad Electronics)
PCB, ref. 080054-1 from www.thepcbshop.com