gear display




February 12th 2013




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Vehlow’s digital gear display

The published electronic circuit layout on this page is based on an enhanced development of Dietrich’s idea done by Joerg and Wolfgang Vehlow. In the context of – motorbike riders for motorbike riders - this idea can be copied, reproduced  and improved at any time for private reasons. Industrial production is only allowed with the agreement of the developer. Please find the story of Wolfgang Vehlow below.

Wolfgang Vehlow with his friend on a tour in the DOlomiti mountains
- Wolfgang (with the green XJ 900) - here in the right corner of the picture at the Timmelsjoch (picture can be loaded in zoomed mode. Just click on it. 168kb).

Hello Dietrich, in 2001 I have enhanced the digital gear display, based on your original design (built with CMOS and printed pcb). Now my son and I have built the whole design based on a PIC (programmed interrupt Controller). The whole circuit consists now only of an IC a few diodes and a few resistors. It is now very easy to build it.

As sensors we have used unipolar hall-sensors. The whole design was focussed on using less mechanical parts and can be completely molded into epoxy. The program design of the PIC was structured that way, that you may use now displays with common anode, cathode or even LCD displays. The layout can be setup for motorbikes with 5- and 6-gear gear boxes.

I have tested the whole design during our vacation trip over 3000 km and it works without any problems. Since we also live the spirit – from motorbike riders, for motorbike riders – everybody on the web should be allowed to build and use that design for private purposes. This web page may also be linked. I would be pleased, if many users would install this useful device on their motorbikes. The only prerequisite is, that nobody makes profit out of it and that you label my copyright. If someone needs a pre-programmed PIC, he can get in contact with me and I’ll send one back based on a small fee and a voluntary donation.


The digital design

I’m absolutely no friend of TTL technology and a mechanical solution was not an option. Therefore I’ve had to look for something that works without mechanics or contacts. During my research I found the hall sensor TLE4905L. These sensors toggle already on a very low magnetic field and switch pin 3 to ground. Pin 1 should be connected to power supply that ranges from 3.8 - 24V. Pin 2 is ground. I have installed the hall sensors in empty relay housings and molded it with epoxy.

digital gear display as LCD solution

This first kit I’ve had in my motorbike for nearly 1.5 years. Everything worked perfect. But since the LED display was hard to see in very bright sunshine I decided to rebuilt the whole kit and change to a LCD display solution. Instead of a complete circuit redesign, we changed to the PIC layout. The advantages from that solution have been explained already above. The prototype was tested extensively during several motorbike trips in South Tyrol. Since the test was successful, we would now like to share that project with other motorbike riders.

The listing is not published as a text file, but as an ASM file. That has the advantage, that the people that do PIC programming,  can use this file directly for programming. The listing is the file gear shift v.1.2.301103.asm. The file can be read with a text editor. We recommend to buy the parts you require to build that unit from, since it turned out that Reichelt offered for all parts the best price.



pcb layout
sesor for the gear lever
installation on the motorbike

Bill of material: price is price per each based on Reichelt Elektronik

parts for the main circuit board




price / Euro


PIC 16F628-20



socket GS 18



90° angle pcb conncetor WSL 10W



fuse 1A



metal film resistor 150 Ohm



metal film resistor 2,2 kOhm



metal film resistor 300 Ohm



connector blocks 3 pins LU 2,5 MS 3



connector blocks 2 pins LU 2,5 MS 2



jumper SW 2,54 mm



Z- diode 5,1 volts



capacitor 470uF / 16 volts



voltage regulator 7805



capacitor 100n



pcb for printed circuits



housing  SP 2029 gr



various silver wire connections on the pcb


parts for the connection panel



connectorr PFL 10



flat cable type AWG 28 10wires a total of 6ft.-1,55Euro, 30ft- 4,30Euro und 90ft - 5,30Euro



The cable connects the sensor with the neutral gear switch, to power and to the display.


parts for the gear lever sensor plate



hall sensor TLE4905L



pcb for printed circuits



housing (e.g. empty relay housing) installed near the gear lever


parts for the display panel



LCD display 2 digits 13mm 


Now to PIC programming. I still believe in the motorbike riders community. If someone requires a programmed PIC, he can get it from me at cost. You can transfer the money after receipt of the PIC. That would be then a so called hardware - shareware - project. Nobody should start to built that unit who is not well trained in building electronic equipment. I definitely will not offer support to neophytes that try to build that unit without the required background. If however someone has a real problem and has the background in building assets like that, I will have no problem to deliver support by just billing the amount of time used.

For the publishing on this website, I have drawn a printed circuit board layout, which you can download with the file board pic.pdf. I own the file PIC.lay, which allows mass-production at a professional pcb factor. If you want to produce your pcb by yourself, just contact me and I will supply the file, which you then can have produced at / To my understanding the cheapes solution..

  • you can get the file PIC.lay from me on E-Mail (
  • you need to delete the “nospam” in my E-Mail address. That’s just a SPAM protection
  • then contact the pcb manufacturer to have the pcbs produced
  • either download the PIC program from this website or write your own
  • or you ask for my bank account details, I ship the programmed PIC and you transfer the cash.
  • order all parts at and build the gear display unit.

So I hope that I have now made you nervous for a new thrilling project for your motorbike and wish you all the best

Wolfgang Vehlow living in Datteln (with special thanks to The Alpentourer Dietrich & Heidi)



[digital gear display]   [Vehlow’s gear display]   [ELV gear display]   [Schwaboiler]   [GPS mounting] [video installation]

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