Reading rotary hall sensors

I have an industrial joystick that I need to interface with a simulator which is programmed to work with gaming joysticks. The gaming joystick board is made to read pots, but the industrial joystick uses halls.

The joystick brand is elobau, a german company. It has 3 analog thumb levers and one analog joystick axis. The hall sensors look like pots. They have 4 wires each. When I disconnect them and supply 5v the other two wires put out a steady 4 and 2 volts. I've connected them to my oscilloscope and they don't show any variation with movement that I can see. I can't find data sheets for the rotary halls. The base one is labled:

elobau
J4C6AA20GA0054C
V1.17/SN 0x01 B1
made in germany
28/11

face thumb lever:
175DT1A1SW13

back thumb lever:
175DT0B0SW05 the B could be an 8

If anyone can give me any tips on reading these I would appreciate it. I'm going to see if it could be a differential signal I need to amplify, but if that doesn't work I'm out of ideas for the moment.

Are you sure they're Hall devices and not rotary encoders needing some sort of AC excitation?

Some of the Elobau stuff uses the industry standard 4~20mA current loop. I wonder if your devices are the same?

alec_t, I'm basing that off of the datasheet for the joystick.

tronitech, I hadn't thought of that, I'll read about it and check.

alec_t, I'm basing that off of the datasheet for the joystick

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Can't argue with that

where is this datasheet?

I can't find data sheets for the rotary halls.

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I'm basing that off of the datasheet for the joystick.

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So do you or don't you have a datasheet

I have one for the whole joystick, I don't have one for the halls. Here is the link to the specs and sheets I have found: **broken link removed**

It seems to say that they have 0-5 v output, but I haven't found that to be the case. This is the CAN bus version, but i don't think I have time to set up a CAN host which reads the joystick and looks like a USB gaming joystick to a PC, so I'm trying to shortcut it and just read the halls.

Could the Hall device in the stick be a TLE4990? If so, two of its four legs (GND and TST) need to be grounded. Check the datasheet for that chip.

I've solved the issue but I don't know why it works. If I disconnect the hall and connect power to the appropriate two wires, I get a steady voltage from the other two. If I power it by powering the control board of the joystick with 24V, the leads in to the halls supply 5V according to my multimeter, but now the outputs vary 0-5 and 5-0 volts when I move the hall shaft. Could it be that it needs a pretty good amount of amperage to run? When I used 24 v to the main board it was from a big 10 A power supply, when I tried 5 to the hall it was a little 0.5A 5V because I don't have a large 5V supply. I'm not sure what else could be going on there. I'll try measuring the current when it's working to see, but for now the problem at hand is solved, the gaming joystick board takes 0-5V signals, so this will work.

4 wire hall sensors are often differential types, they have 4 magneto resistive elements in a bridge. You attach DC volts to 2 pins, and the other 2 pins vary differentially with changes in N or S pole magnet applied to the sensor. They are usually not that sensitive and need the differential pins connected to an opamps dual inputs.

Be careful you don't kill it with 24v, they normally run at a few volts, or better still a few mA into the + pin.

If I power it by powering the control board of the joystick with 24V, the leads in to the halls supply 5V according to my multimeter, but now the outputs vary 0-5 and 5-0 volts when I move the hall shaft. Could it be that it needs a pretty good amount of amperage to run?

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Strange indeed. My brief research on Hall devices of the type used in joysticks and other position sensors indicates supply current = 5.5mA max. But some types apparently need to be triggered by a micro before they output measurement data, so with the Hall device disconnected it maybe sulks