I have also prepared a digital gear indicator, for whom are interested in.
Although I have tested the circuit on pc program you may need to change the capacitor and zener diode on your real circuit.
Red line you see on the diagram will be on the top surface of the pcb, you may simply use two wires to connect those pins.
Circuit includes the control unit that produces 1st gear signal, U1 encodes the gear input signals and U2 decodes them and sends to display.
Hi Erdeniz, indeed your design is great but I need your help, for I built the indicator but can't make it work.
My knowledge of electronics limits me to follow some circuits, can't analyze digital signals.
To begin I must say it's my first time making my own Pcb, used the hotiron method, and the very first one was mirrored, I realize that after have soldered all parts and T1 looked backwards, anyway it served me for the purpose of adjust the signal for 1st gear; the lowest zener value available here is of 2.4 V. and in conjunction of a 330 mf capacitor I'm getting about 2 seconds delay which suit me.
For a bench test I set up a series of 7 diodes resembling the 7 segment, ( which is already fixed in the bike and not available) and hooked everything in a moke up ( picture attached)
To test I have an analog and a digital VOM;
My measures say that even when both IC are connected in parallel there is no power at pin 16; and 5V at pins 9 thru 13.
By grounding the leads simulating the gear switch sender I can see the first part of the circuit works Ok.
In the picture showing the Pcb, could it be that a connection is missing between U2 pin 16 and +B??
Thank you in advance, I'll really appreciate if you can lead me to complete this job.