These look useful, long life with much improved relaibilty and works just like a normal pot. Added bonus is a range of swept angles 35 to 360 continuous so no need for any gearing to maintain resolution. Definite upgrade item if the rest of my rig works out. Tad pricey though £10 to £15 for one offs :(
http://uk.farnell.com/bi-technologies-tt-electronics/6127v1a90l-5/sensor-hall-0-2v-20v-to-10v-pin/dp/2319673 (http://uk.farnell.com/bi-technologies-tt-electronics/6127v1a90l-5/sensor-hall-0-2v-20v-to-10v-pin/dp/2319673)
(http://uk.farnell.com/productimages/large/en_GB/2319659-40.jpg)
Another great find H, Tell me you live online lol.
DD
Like to surf if the television is on - most programs only hold my attention in small snippets ;) missus complains that i watch 3 programs at once if i have the channel hopper (remote) in my hand, it is possible with the ad breaks these days ;D
I dont have a TV so Im safe from the disease "mustaswitchachannelitus"
The Hall pot is the way to go but nearly 3 times the price of a heavy duty P260 vishay pot
DD
Might get more reasonable in quantity ;) and you can reduce the complexity and component count elsewhere to balance the cost a bit - but yes, pricey. I think it will be one of those items that get cheaper as they become more mainstream - the advantages are just too obvious and i'm sure (better) equipment manufacturers will make the move to the newer technology eventually.
I can 3D print the gears for pennies as they dont have any pressure on them but I WANT hall pots and sensors no matter what. I think its best for me to have them as an option if the customer is willing to pay the extra. Too many dont understand the cost of building systems and make it hard to build quality without the cost. Also mass produced is far different from hand made!!!
People need to wake up and stop comparing a bike controller cost to the steering wheel systems!!!
DD
Nearly all the top end wheels have gone hall effect due to issues with steering center point drift when using traditional resistive sensors and it is cheaper and simpler than optical encoders
Quote from: h106frp on February 01, 2015, 08:57:35 PM
Nearly all the top end wheels have gone hall effect due to issues with steering center point drift when using traditional resistive sensors and it is cheaper and simpler than optical encoders
Oh, I thought wheels used optical encoders.
MaX.
Its the optical encoders that have been hving problems, G25/27 seem hit pretty bad. There are fixes for it but who wants to HAVE to fix something that should work?
I would love to use the best on my systems and I have designed them to use different types of sensors so people can upgrade if they want to save money to start with, or just pay for the best components from the start. Its not an easy market.
DD
Thinks its the T500 where they have changed,
High end custom wheels use an (industrial)encoder, for consumer grade production units hall effect is a fraction of the price of a high resolution encoder (you would need 1024 ppr quadrature absolute for similar performance angle sensing - or a cheaper unit and a lot of gearing) and does not need extra processing for direction and angle.
Yeah I need to get some and test how they are but it can be expensive if you have to buy so many to test the ACTUAL way they are on a system with different angles of rotation and I learned a long time ago it is NOT something you can calculate, feeling is a human factor not a mathematical calculation. You would not believe how many springs I have purchased over the years to get things right for levers and throttle etc.
DD
Might try the home-made route as suggested in this link for hall effect pots for feedback - geared pots are not the best for smooth servo feedback ;)
http://www.mycockpit.org/forums/showthread.php?t=22267 (http://www.mycockpit.org/forums/showthread.php?t=22267)
I love that H, with my new 3D printer it would be so easy to make a body to replace the wood and make it neater. Just got the grant at 3AM on my bank so got the GO dude...........WOOOOOOOOOHOOOOOOOOOOO
DD
Snagged a few sensors, £2 ea for the more sensitive version (twice the volts out per gauss). Probably modify an old potentiometer as a test housing to generate some test data and report back once tested.
Would be nice to have a proper 3D printed housing, and might make for a very economic low noise rotary sensor.
Been some interesting announcements this week with new 3D printing methods, its certainly the production method of the future.
H we can work together bro, you send me a 3D design to print and I can print it for you. We are a community and if people need 3D printed parts I am totally up to let anyone use my printer to do it, just need the 3D model and in STL file type. I aint interested in making money from such a thing, cover the cost of ABS or PLA or Nylon(have to test nylon yet) is all good. I will even sign a doc to say I wont steal a design if you know what I mean, this is for all of us.
DUDE time to work together..........................
DD
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.
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 :)
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
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
(http://i.stack.imgur.com/ghc2b.png)
@DD what range of gear MOD can you manufacture? can you get less than MOD0.5?
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
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 (http://www.ebay.co.uk/itm/15-MEGA-STRONG-Neodymium-Rare-Earth-Magnets-SQUARE-DISC-10-x-10-x-2-mm-/131096649087?pt=LH_DefaultDomain_3&hash=item1e85f81d7f)
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://lh6.googleusercontent.com/-dI4PSpjlHb8/VRsW16RFtPI/AAAAAAAAAMQ/iXcyKndt5fM/w1512-h849-no/WP_20150331_001.jpg)
(https://lh6.googleusercontent.com/-NQgOUX7zHaQ/VRsW4KmWoEI/AAAAAAAAAMY/WT07sONYyS0/w1512-h849-no/WP_20150331_002.jpg)
https://www.youtube.com/v/ZQpUIBAEqYg
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