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March 28, 2024, 11:33:17 AM

Hall effect pots

Started by h106frp, February 01, 2015, 04:43:19 PM

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h106frp

Might have to take you up on that if the sensors are any good but i will have to improve on my usual 'fag packet' drawings though. Noisy carbon track pots and gearing are not the way to do the servo position feedback, i have found the noise level (pot crackle) means you have to keep the feedback loop gain lower and the gear backlash (only found mod 1 gears locally with 6mm bore  and using smaller bore will mean making new parts) causes the drive to 'step' slightly. I think the hall effect device is probably the best long-term solution.

Not bothered about anyone using my ideas, it's just a bit of fun for me building these things:)

Progress is good on the steer axis, ghost rider is happily steering my powered bars while i play the sim and the whole contraption is now under reliable control - wrecked 2 microswitches and bent several 6mm high grade steel steering lock bolts in the process though ;D Instrument cluster is finally complete with permanent circuitry and ready to mount on the rig as well, a job i have been meaning to complete for a while now.

Will try and post a progress video if i get a chance at the weekend.

Great to hear your finally up and running with the business, i will keep an eye on your web site for developments.


teeds

March 25, 2015, 06:39:09 PM #16 Last Edit: March 25, 2015, 06:41:13 PM by teeds
Quote from: h106frp on March 25, 2015, 03:23:47 PM
Snagged a few sensors, £2 ea for the more sensitive version (twice the volts out per gauss).

Have you gone for the  2.5 mV/G version of them? If so would you mind posting what rotation amount gives full voltage range please? Might give me some more fidelity options if I'm thinking right about the mV/G differences.

Be good to see that video  :)

doubledragoncc

Its because of the price and choice of gears that I am going 3D printing, cost is down from £5+ to 10-20 pence!!! go figure what I will chose lol. It is housings and gears that are the problem so thats where money and design can be beaten. Also means can offer a SET of gears so people can chose what suits them best which cant be done with just one potentiometer be it standard or HAL.

Seriously dude we should bump head more...........

DD
GPBOC Live Streams: https://www.youtube.com/c/IASystemsComputerControls; i7 12700K 5.1GHz Z690 ASUS Strix Z690-A Mobo 32GB 3600MHz DDR4 RAM ASUS Strix RTX3080 OC 10GB DDR6X ASUS Ryujin 360 AOI Cooler ROG Thor 1200w PSU in ROG Helios Tower Case.

h106frp

March 25, 2015, 07:05:09 PM #18 Last Edit: August 07, 2015, 09:36:14 AM by h106frp
Yep, 2.5mv/G, guessed it would allow less exotic (expensive) magnet choice. Only just ordered so it will be a few days before i can try them out.

The linked thread suggests 160-180 degrees usable rotation and i suggest using them with a single dual op-amp zero and gain circuit to derive any electrical output range you need, i.e bi-polar or uni-polar. I have used the same circuit to convert the uni-polar 0-5volt output from my microcontroller to +- 10volt bipolar input on my servo controller and it works great. One side of the op-amp generates a buffered offset voltage and the other side the required gain range.

I borrowed this circuit idea and it works perfectly with any low offset (precision) op amp


@DD what range of gear MOD can you manufacture? can you get less than MOD0.5?

doubledragoncc

Its a 3D printer so there is no limitation to the MOD of the teeth dude, send me the stl file and I will print it. I can use PLA and ABS but should be able to do nylon too (Taulman Bridge) as my extruders can go to 260 degrees C and only need 240.

I am only just learning it all myself bro but if I can give a service to you guys for free why the hell not lol. For gears and small stuff I dont want a penny, only if its a lot of plastic will I want the material cost covered.

DD
GPBOC Live Streams: https://www.youtube.com/c/IASystemsComputerControls; i7 12700K 5.1GHz Z690 ASUS Strix Z690-A Mobo 32GB 3600MHz DDR4 RAM ASUS Strix RTX3080 OC 10GB DDR6X ASUS Ryujin 360 AOI Cooler ROG Thor 1200w PSU in ROG Helios Tower Case.

teeds

March 26, 2015, 09:47:10 AM #20 Last Edit: March 26, 2015, 12:27:21 PM by teeds
That's a seriously tasty bit of kit you've got there DD, may your creations be precise and profitable!  :)

And I tried a few different shapes and sizes but these gave the best results, cheap too linky

h106frp

March 31, 2015, 10:21:53 PM #21 Last Edit: May 22, 2015, 02:26:07 PM by h106frp
Got a device into an old ten turn potentiometer body, almost made for the job and just needed a bit of filing to make flats for the magnets, sweep is 180 degrees gives 100mV to 5volts, rotation is continuous with the next 180 degrees going 5volts back to 100mV. Seems you could make excellent cheap sensors using 3d printed bodies based on this configuration. Next step is to use this for my servo feedback sensor and see what improvement i (hopefully) get  :)



https://www.youtube.com/v/ZQpUIBAEqYg

doubledragoncc

I just did a series of test print H and was very surprised at how the PLA that shipped with the printer worked out. At 0.1 microns its lovely. Gear teeth are perfect and for housings it would be the solution. My old gears cost £7 each and I needed 10, now it takes 15 mins to print one for 5-10 pence! BIG difference in cost. Ilike the Vishay P260 as it is VERY small 14mmx14mmx32mm with 6.3mm shaft, very precise and long life as they are heavy duty. At £4.45 they are not expensive too. I am going to make a GTA V specific controller a bit like a gamepad but with real P260 pots for steering of cars and bikes.

I actually need to talk to you if possible H, could you PM me a way we can talk, not message? Thanks if you can m8.

I am working together with the guys from the technical university in Malaysia on a full motion rig and they are looking into sourcing electronics for me as well so if I get any good leads will post them here.

DD

GPBOC Live Streams: https://www.youtube.com/c/IASystemsComputerControls; i7 12700K 5.1GHz Z690 ASUS Strix Z690-A Mobo 32GB 3600MHz DDR4 RAM ASUS Strix RTX3080 OC 10GB DDR6X ASUS Ryujin 360 AOI Cooler ROG Thor 1200w PSU in ROG Helios Tower Case.