DIGITAL GEAR INDICATOR

 Introduction


This is a new design for a universal gear indicator that can be fitted to any motorcycle as an aftermarket accessory. Its main advantage is that its operation depends entirely on the gear shift lever movement, instead of connecting to speedometer and tachometer sensors (found in expensive commercial devices), which are rarely available in older motorcycles. It consists of a main circuit including a 7‑segment LED indicator, two Hall sensors that are attached to the motorcycle frame, and a small magnet placed on the gear shift lever.

Download source files in .zip format (v1.3 - 12 Aug 2010)

Download PCB top layer in .pdf format

Download PCB bottom layer in .pdf format

Download PCB silkscreen in .pdf format

Parts List

Part	Value	Comments (for suggested PCB)
R1	10 to 220 Ω ½W	Depending on preferred LED brightness
R2, R3	10 ΚΩ ¼W
C1	220 μF / 35V	Electrolytic capacitor
C2	100 nF	MKT/polyester capacitor
MCU	ATTINY25/45/85	Mouser Part 556-ATTINY25-20SU
COUNTER	4026	Mouser Part 595-CD4026BPWE4
IC1, IC2	Hall sensor	Melexis US5881LUA (available from adafruit)
IC3	7805	5V Regulator TO-220
BLUE	Kingbright 0.3"	Mouser part 604-SC03-11PBWA/A
RED	Kingbright 0.3"	Mouser part 604-SC03-12EWA
JPx	Pin connectors	As shown in silkscreen and pictures

Possible improvement 

In the current design, when the neutral switch is open (there is a gear on), 

there appears to be a very small current (< 0.5 mA) sinking through R3, due

 to the voltage difference between the neutral switch connection 

(TO_POWER-4) and the microcontroller. If the neutral indicator is of LED 

type (not a resistor bulb), there is a possibility that it stays dimmed, instead 

of being completely off. In that case, a small switching diode (1N4148) can 

nicely replace R3 (on the same PCB) in order to block this small incoming 

current when the neutral switch is open, as shown in the figure below : 

FINAL

Connections

Installation Photos

Here are some photos and videos from the installation on my suzuki Intruder VS400 :

Custom Housing

Installation Videos

Installation1.avi 

Gear shifting by hand

Installation2.avi

 Real gear shifting with engine on

Installation3.avi

Storing last gear in EEPROM

Action Video

Thanks for reading !

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