Jörgs Motorcyle Pages: Speedometer adapter for ACE-TA7, e.g. BMW 2V airheads and Moto Guzzi


What is this page about?

ACE-TA7 Pulse Shaper PS-A

The company Acewell markets a range of "Digital Speedometer Cables" such as the ACE-TA7 (labeled as ACE-S11 in some countries). They can be used instead of the original speedometer drive. Essentially, these units contain a Hall effect sensor. The sensor generates an electrical signal; the frequency of this signal is a function of speed. This signal can then be processed further with an electronic speedometer.

It would appear that these units were developed only for Acewell's own instruments; a data sheet e.g. for the ACE-TA7 seems not to be available (as of May 2013).

To enable the use of these sensor units with other types and brands of speedometers, I have developed the level shifter PS-A presented here.

A comment from a satisfied customer in the UK (2017): ... received the PS-A and installed it no troubles at all, worked first time with the Motoscope Pro. I am also really impressed with the craftsmanship of the product. The encapsulation in the black epoxy and the clear window of the PCB is flawless and impressive. I lead an international team whom is currently semi-finalists in the ongoing $7m Shell Ocean Discovery XPRIZE competition, which is looking to evolve large scale robotic subsea scanning. You can see more about it on our website: www.team-tao.org
The reason for my email was to say some of the PCBs on our robots are encapsulated in a hard epoxy to make them pressure passive but the aesthetics of the finished encapsulation is not any where as good as your's and was wondering if you could please provide some basic tips. [...] I really appreciate you’re input. Kind regards, Dale
. -- Thanks a lot, Dale!


The PS-A is available since summer 2013. If you are interested, please order via this page.

How it works

The Hall sensor unit, such as the ACE-TA7 (which you need to buy yourself!), receives its supply voltage from the PS-A. Per every revolution of the encoder - the "speedo cable" -, one pulse train is generated.

The PS-A converts this "noisy" analogous signal of the sensor into a well-defined digital signal.

The detailed circuit is not open for discussion; however, the circuit contains:

Suitable speedometers

Speedometers tested

The following is a complete list of all speedometers that have been tested and reported back to me. If a specific speedometer model is not listed, this simply means that it has not been tested yet ... or nobody bothered to share the results. This list is updated with feedback from the community, i.e. your feedback.

As a side note: please do not ask "do you have any news regarding the speedometer XY". The current status is always listed in the table below; even a Fail is fine for me. I do not have the intention to make "all" speedometers work with this unit ;-)

Those who feel a need to get the circuit adapted to a specific speedometer model can commission a custom made adapter. You will need to send me the speedo in question for a few days so I can develop and test the circuit with that specific speedo unit.

Manufacturer Type Result Remarks Contributor
Motogadget motoscope mini/classic/pro, chronoclassic Pass Motogadget
Motogadget motoscope tiny/speedster/vintage Pass Please order "PS-A-Tiny", the standard PS-A-12 will not work with the Tiny. Own test (JHa)
Motogadget SureShift Pass Motogadget
MMB E-Tacho D48 and D80 of 1st Generation Pass MMB says "W>1000 desirable, otherwise the instruments might oscillate." MMB
MMB ELT48, 60 und 80 Pass MMB says "W>1000 desirable, otherwise the instruments might oscillate." Clients report that W=691 is perfectly stable. MMB & User
Touratech IMO 100R300 Pass User
SIXO SIXO 2.0 Pass Very stable, MAX speed works as designed User
KOSO ? (old model without ID) Pass Use the gray wire (of the original Hall sensor connector) as speedo input. Own test (JHa)
T+T und KOSO Multifunktionsinstrument "D-Serie" (KBA 91397) Pass Use the white/brown wire (of the original Hall sensor connector) as speedo input. Own test (JHa)
Daytona Velona Pass works as designed User

Other speedometer types?

Your speedo is not listed above? I can eventually provide a test circuit that emulates the signal of the transducer at two different speeds upon request. If you are interested (especially as speedometer manufacturer), please get in touch with me.



Installation is basically simple since there are only 4 wires: input from the speedo sensor, exit to the speedometer, supply voltage and ground. Detailed instructions are, of course, included.

Here is the "but":

Technical Data

Hall sensor Input

The PS-A was designed specifically for the Hall sensor ACE-TA7 and I have good reasons to believe that most of the ACE-S... types should work, too.

Output to Speedometer

The signal at the output of the PS-A is a square wave. In the standard version PS-A-12, the signal level switches between "almost ground" (LO) and "almost supply voltage" (HI). A special type PS-A-5 is available where the HI-level is limited to ca. 5 V; other versions are available upon request.

The output line has a built-in resistor that provides short-time short-circuit protection.

Due to the construction of the ACE-TA7, the duty cycle of this signal is roughly 50%.

Power Supply

The PS-A requires a power supply of 12 V DC (nominal), usually the power supply of the motorcycle. The circuit is active as soon and as long as the supply voltage is applied and can operate down to approx. 8 V.

Two LED provide an indication of operation. They light up with the rhythm of the signal; one of the two LEDs is always lit.


Diameter ca. 20 mm, length ca. 52 mm, weight ca. 40 g (typical). The entire circuit is potted in epoxy and painted, thus protected against vibration and weather.

What else?

Legal Notice

Important Note: The PS-A was developed without any support from the company Acewell. All data were obtained experimentally and tested under various operating conditions so that, according to the data that I have, reliable operation should be given. However, since I can not guarantee that the sensor will be made with the same specifications in the future, I cannot guarantee that the PS-A will work with future versions. Thank you for your understanding.