I have a saitek ST290 that i modded to a full length stick, ive been using for a couple years now and the pots are spiking. I purchased some hall sensors (allegro 1321) and rare earth magnets but the controler does not recognise the hall sensor.

Has anyone here done this or know what i could do to make it work? The original pots are 3 wire, between the middle and either of the outside terminals the voltage changes from 3.2vdc to 0vdc when turning the pot. The original pots are 50k ohms.

I know i could buy the leo bodner 0836 board and use that but i am trying to save a little money and maybe learn something too in the process. Im not sure if i wired it correctly, I know i did not damage anything yet so thats good.

Any help or suggestion are apreciated.


52willys

This MOD is feasible.

These A1321 work with 0 - 5 volts, so you need took +5v voltage from any 5v point in ST290 circuit, none in original pot cables (3,2v). Look at point where USB cable enter in the circuit.

I see some "how to" about these HALL sensor MODs, but in Russian forum (Google translation):

http://translate.googleusercontent.com/t...5yUqMyJqrdwGgmg

EDIT - As far I understand from above link, every if you take +5v direct from USB cable, the USB circuit (calibrated for 3,3v) in stick reduce voltage above +4v and one axis dont work, so you need ad a few components (resistor, trim pot..) to induce circuit "think" that have a 3,3 volts sensor plugged ...

Pictures from thread in this file: http://www.4shared.com/file/R6y_yWC_/EvoHALL.html

Another thread: http://spread-wings.ru/phorum/index.php?s=571c9f0bdd057fb30ff622766c2ec8fc&showforum=11

These pictures bellow are related to replace 3,3v pot with 5v HALL.

http://img46.imageshack.us/img46/9205/hall5v.jpg >>> Accord first link if plugged like this scheme one HALL dont work.

http://img577.imageshack.us/img577/9205/hall5v.jpg >>> Resistors to circuit "think" that have 3,3v sensor plugged???

http://img510.imageshack.us/img510/236/hallx45ss495a.jpg >>> Something related to Saitek X-45...

(Honeywell) SS495 - show in drawings - work at same voltage than Alegro A1321 (~5v).

Other point: if you replace pots with HALL sensor and go to Windows control panel to test, you dont see response.
You need first calibrate the sick with the new sensors and apply calibration.

Sokol1

Thanks sokol,

I had it wired wrong to start with, once i used the USB ground as reference i realised that i had wired incorectly. Saited uses brown, yellow and green so looking at the hall sensor side with writing on it terminals from left to right 1,2,3 the brown wire goes to 1 yellow 2 and green 3.

Then it worked, but it still only had 3.2v input and in the windows calibration window it will only go from 0 to 780 with 3.2v. I did wire 5.0vdc off of the USB and then that changed to 0 to 1000 but i only tried it with one hall sensor conected.

Thanks for the links above i will look and see what i need to do. Is there something i can put in the circuit to protect my USB if i were to accidently short the 5vdc? That my only concern at this point.

Couple questions on these two links

http://img46.imageshack.us/img46/9205/hall5v.jpg Is this is a 50kohm pot conected to the output of the hall sensor and then conected to the control board? What does the 2.2 indicate on that drawing? I cant read that box.

http://img577.imageshack.us/img577/9205/hall5v.jpg Do you know what resisters are on that diagram? I cant tell where the red and black lines are suposed to conect.

Thanks again sokol

52willys

52willys,


The thing labeled 2,2-50k ind drawing is a variable resistor, or trim pot.

Sorry, I dont able to read Russian...

I ask (in english - not my best) to CrazyDoc in CCSquad, and their answer:



In short: to HALL sensor (A1321, SS495...) work they need 5v. Took from USB cable.

But the Saitek Evo USB Circuit dont support 5 volt, so you need tuned down the voltage incoming from HALL Sensor to Evo circuit, to this use one 2,2-50k trim pot.

Sokol1

Real quickly, I am by no means an expert on this subject, but I am currently doing a hall sensor mod to my TM Elite rudders that I am intergrating into my multi-use desktop sim panel. I am adding dual toe brakes axis. I am using HE sensors not for their superior sensitivity and accuracy, but for their tiny size compared to a potentiometer. They will fit in an area MUCH smaller and less obtrusive than a pot. Besides, I dont want to have to go taking the pedals apart, just to clean the pots every now and again. Dust and dirt have almost no effect on a HE sensor, unless it is made up of metal iron filings.

On to offering what might be a solution to, and hopefully helping you find an answer to your problem.

First of all, some of the older controller boards in joysticks, HOTAS and other controllers, use a variable resistance as the reference and to operate, and not a variable voltage. Hall effect sensors send a variable voltage to the controller interface. If your CI board operates on a variable resistance, then the HE sensors will not work. At least not without a circuit to convert the variable voltage to a variable resistance. It can be done, but is above my expertise and not neccesary to what I am doing.

You have already stated that you had it wired wrong, so you may already have found your solution, but for clarity I am including the info here for others.

The thing is, and I can not speak specifically to the Allegro 1321. but with the Alegro 1302s that I am using, to wire it up, you can not do a one to one wire swap. A visual may help, so there is a picture of the HE sensor I am using HERE. The swiper on pots is by in large the middle wire. With the 1302s. The swiper, or reference voltage that the controller sees and uses to determine the axis position, is the outside lug.

The ground and 5v are the middle and one of the outside lugs respectively, the reference is on the other outside lug. If you are trying to use the center lug, you will never get it to work. As a matter of fact, you can blow the HE sensor up by wiring it the wrong way. I hope that is not the case, else you may be trying to wire a component, that is already blown.

I am using the BU0836A from Leo Bodnar, and am starting construction of my desktop sim control panel in earnest, including mods to existing controllers which will be interfaced through the new sim control panel.

I will be posting a log including photos and detailed descriptions after I am finished with the basics of the panel.

Finally, i found some time to finish this project, I got some better magnets 3/8" cube N45 and these worked better.
With the new magnets i get full range of movement using the 3.2vdc from the 3 pin plugs that the original pots are wired to, so i did not have to wire from the 5vdc usb supply.
I have tested it for about a week now and it is working great flying IL2. I really like how flexible these sensors are, i was able to reduce the movement of the stick to 36 degrees and still get full movement and sensetivity, much improved over the pots. I am very pleased with the results and would like to say thanks for the help.


52willys