Zusi-Forum

I have a Teloc A28 speedometer manufactured by Hasler AG Bern. I'd like to connect it to ZuSi. Can anybody help me how to do this? I don't know how to program a microcontroller etc... :S

Do you have a pic of it?

Is this one of the newer ones with a stepper motor inside?

It is the A28 with a three-phase AC motor inside.
http://www.ipolyerdo.hu/pics/upload/tobi003.jpg" target="_blank - like this one

Okay, so that's pretty much the same one I used with my ÖBB 1042 driving simulator.

Like I mentioned in the other thread, the easiest way will be to replace the original AC motor with a DC Gear motor, which can easily be driven by a Microcontroller with PWM funcion (e.g. Arduino) and a PCB Plate with an optocoupler and a mosfet.

Here are some pics of my solution:



My Hasler speedometer needed 800rpm so I've used a motor with max. 1000rpm. It isn't 100% acurate at lower speeds (<15km/h) but it's good enough.
The only alternative is to use an expensive industrial inverter for the original motor.

Ok. So I need a new motor. My speedometer needs 800 rpm to display the maximum speed. (90 km/h) Could you help me?

First you'll need a DC Motor with ~1000rpm, I've used this one.
Anything with more than ~6 Watts whould do it.

Is it the Modelcraft 7127c? What else should I purchase?
You've mentioned in the other topic, that you've invented a frequency converter. Wouldn't be easier to use that technique?

Any motor with similar torque and rpm will do it.

The layout of my frequency generator was pretty complex and I haven't got it working reliably. If you're not very practised in electronics it will be much easier to use a DC motor.

If you want to build the inverter, here's the cirquit (I recommend to use faster diodes):

Hi,
I've ordered the DC motor. What else should I buy? What's the next step?

Thanks in advance!

You'll need an Arduino and a PCB board to run the motor via PWM. This isn't that complex, basically you'll just need an optocoupler, 3 resistors and a Transistor (=> MosFET is better). My layout (with 4 channels) looks like this:

PCB-Layout:

It sould then look something like this:


There are already a lot of threads how to connect all this to Zusi with the arduino, however, mostly in German.

I recommend using a PC power supply, it gives you all the voltages you'll need and you'll get them quite cheap.


To connect the motor mechanically, you'll need a coupling between the motor and the Hasler Speedometer. I've built one on my own, you can see it in my pictures. It's pretty much the same as the original one, except the hole in the middle is bigger to fit onto the motors shaft. You can use the original one and drill a bigger hole, I just wanted to keep it like it is if I'd ever use the old motor again. (But it seems like I've lost it anyway )
I also recommend to use a small flywheel (which I din't), it will improve the accuracy at lower speeds.

The motor mounting is a simple steel plate and 4 screws, souldn't be that hard to copy

Greets,
Sebastian

For curiosity's sake: Why is the optocoupler necessary?

I've implemented them for galvanic separation in case of a failure of a MosFET

But you're right, they aren't nececcary.