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#4375212 - 08/18/17 05:06 PM Cougar hall sensor issues  
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Povlhp Offline
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Povlhp  Offline
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Aarhus, Denmark
Found my old HOTAS cougar - serial <1500.

Throttle pot dead so got some 49E Hall Sensors. Testing with 5V power source the do fine. Connecting it to the cougar throttle connector it does not work. I have 0.7V only between Vin and GND. 4V with no 49E.
With and without signal/Vout connected. Any explanation ?

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#4375217 - 08/18/17 05:42 PM Re: Cougar hall sensor issues [Re: Povlhp]  
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Povlhp Offline
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Well,looking around it seems like there is a 6.7k resistor towards 5V ?
See https://pit.uriba.org/uriba/standalone-cougar-tqs-part-i/

If this is the case, the 1.1k resistance of the 49E would cause a voltage drop of about 1.1/(1.1+6.7) * 5V = 0.7V over the 49E. This is exactly what I am seeing.
But the actual voltage is only around 4V without the load. That matches better with 5V and a 1N4001 (1V voltage drop). Any help ?

Next step must be to test with just a 1k resistor. Do I get the same voltage drop over it ? If so, I have to "steal" 5V elsewhere for the throttle hall. Any insight welcome.

#4375219 - 08/18/17 05:53 PM Re: Cougar hall sensor issues [Re: Povlhp]  
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Povlhp Offline
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Oh well, figured it out finally.
Not by experimenting, but by searching.
My theory was right. Need to cut the 5V feed thru the 6.7k resistor, and get a clean 5V elsewhere.

https://www.bmsforum.org/forum/showthread.php?24707-Cougar-Throttle-Hall-Effect-Potentiometer-Cubpilot-Reincarnated!

Have to do the mod, then try again. I see people mount the hall sensor vertical on a piece of plastic, and then just magnets on the handle.
I already printed something more pot-meter like, 6mm hole around the 5.2mm 49E. That gave me +/- 0.7V only. More magnets = more voltage.
So moving the magnets along the surface of the sensor will make them get closer, and stronger signal. So this will be my future solution

#4375235 - 08/18/17 07:38 PM Re: Cougar hall sensor issues [Re: Povlhp]  
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Sokol1 Offline
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Early Cougar TQS PCB has this resistor limiting current, last units no:

https://forums.eagle.ru/showthread.php?t=160613&highlight=hall+sensor&page=13

You need by-pass then using different resistor

https://s31.postimg.org/vzjyvu2u3/TQS.jpg
https://forums.eagle.ru/showthread.php?t=160613&highlight=hall+sensor&page=14

Piece of cake! wink

#4375247 - 08/18/17 08:15 PM Re: Cougar hall sensor issues [Re: Sokol1]  
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Povlhp Offline
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I assume the resistor can be a jumper. Assuming it is a 32u4, it can take 5V.
The 220Ohm is 1/5th of the 49E, so would in theory cut 1/5th off the 5V, bringing it back down to the 4V it had before. A diode would do the same, drop about 1V no matter the load, so would be a better solution if other internal resistance of another hall component.

The 49E typically outputs 0.95V -> Vs - 0.95V. So with 5V input, it will output typically around 4.05V max which is safe, and close enough to the max of the old voltage divider. Did the cutting and put a wire in place, now on to test and find best magnet placement at end of handle. Can easily 3D print a magnet holder that will fit into the 5mm cut-off hole used by pot-meter. This is how my first prototype with low voltage range was made

#4375280 - 08/19/17 12:10 AM Re: Cougar hall sensor issues [Re: Povlhp]  
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Sokol1 Offline
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BTW - SS49E is not the best option for DIY HALL assembly, has low sensibility compared to SS495A1 or (Allegro) A1324. But try then don't hurt. smile


#4375360 - 08/19/17 04:07 PM Re: Cougar hall sensor issues [Re: Povlhp]  
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Povlhp Offline
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Povlhp  Offline
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Works ok but not perfect. HOTAS Control Panel gives me a range of around 300 values with my setup. That is 2xmagnets side by side on an adapter in handle, and sensor fixed below the center axis. So when I turn north or south will get very close to the hall sensor. Considers making some 3D printed assembly for it to ensure minimal distance and more locked down relative position.

But works for now.

#4375403 - 08/19/17 09:40 PM Re: Cougar hall sensor issues [Re: Povlhp]  
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Sokol1 Offline
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If sensor has low sensitivity (mVG) the magnet gap from then need be very narrow, ~2mm or less.

#4375478 - 08/20/17 02:31 PM Re: Cougar hall sensor issues [Re: Povlhp]  
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Sokol1 Offline
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A guy that did some experimentation will HALL sensor placement say that this option is the more practical, make easy adjust the center position:

[Linked Image]

Use diametrical magnetized ring magnet (e.g. 11X7.5X2.5mm) and position the sensor inside the ring.


#4375600 - 08/21/17 11:08 AM Re: Cougar hall sensor issues [Re: Povlhp]  
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Povlhp Offline
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Povlhp  Offline
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Yes, the ring magnet is a possibility, but more hard to come by.

The design I will play a bit more with is:
having the sensor on one wall
A magnet composed of 2 flat magnets reversed (giving one long magnet with south to one side, north to another). This magnet will be turned around a center point below the hall sensor, such that when turned 90 degrees north is up, south is down and the other way around. Adjusting center could be done by turning it a few degrees if needed. A grub screw could be used to lock the magnets-holding-thingie to the axle.

But for most uses, center is calibrated independently, and so is endpoints, so if is off by a bit it is not important. What matters is that I have plenty of resolution to each side.

The good expensive hall sensors has a sensitibility 2-2.5x better than the cheap. And since signal degrades with square of distance, you can do with 1.5x the distance with a good sensor compared to a cheap. If we talk 2 vs 3mm, both are easily obtainable with a 3D printer, operating in 0.1mm layers. The glue to hold the components will be thick enough to influence it as well. For now I have plenty of 4x4x1 mm magnets, and they re pretty good for this. Stack 2-3 to improve magnetic field, and all is good.

Will build a test-setup some day with an Arduino, and a display. Easier that juggling with the probes of a multimeter, and I have the parts. Time as a more rare resource.

#4375695 - 08/21/17 04:48 PM Re: Cougar hall sensor issues [Re: Povlhp]  
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Sokol1 Offline
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Quote

A magnet composed of 2 flat magnets reversed (giving one long magnet with south to one side, north to another). This magnet will be turned around a center point below the hall sensor, such that when turned 90 degrees north is up, south is down and the other way around.


That's a good setup too, is the idea behind the "Bic pen HALL pot". smile

http://SimHQ.com/forum/ubbthreads.php/topics/3225807/DIY_hall_sensor.html

Improved by LocNar

http://SimHQ.com/forum/ubbthreads.php/ubb/printthread/Board/81/main/365749/type/thread



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