Air / Fuel Ratio Meter
I changed the value for R1. The meter cycles from yellow to red (rich to lean).
Parts:
IC LM3914 or equivalent
Resistor 2.2 Kohm
Resistor 9 Kohm
Resistor 39 Kohm
Capacitor 10 microfarad 25VDC
Capacitor 10 nanofarad 5VDC(?)
LED 2 red, 2 amber, 6 green Something like 4V or 5V