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Main => Main Forum => Topic started by: waveryder on January 21, 2008, 04:57:46 am

Title: Can't Bullseye Womprats In My T16!!
Post by: waveryder on January 21, 2008, 04:57:46 am

I was going to save this one till I had finished the final version, but I need a little help. You'll have to bear with me on this post as "I feel the force, but cannot control it"  :-[

Episode 1:
First prototype way off target. Badly made and had to completely rethink the whole idea!
I researched everything I could find on building a yoke including a fantastic piece by Menace. But parts have been extremelley hard to come by. So I scraped the whole plan and went back to the drawing board.

Episode 2:
Went a little better lots of action but everything felt stiff and squeaky!
Hmmm sounds like someones acting and directing ability. I got hold of the atari star wars plans (provided by Princess Leia, thats right I mean U) and figured out how I could adapt them to fit my idea of a yoke for "BubbleGum Betty". With the sizes figured out and the spurs aquired I was ready to go. I have aquired a Msoft dual strike for the interface (£2 on Ebay) and was ready to build the second prototype out left overs I had in the garage. Begun cutting a shapping the parts and dremelled my MF*** finger with a cutting bit. Prototype 2 hit the wall as I momentarily went over to the darkside.

Episode 3:
A little better now its finally on track!!

(http://forum.arcadecontrols.com/index.php?action=dlattach;topic=51525.0;attach=93568;image)

Built the control shape and poles and spurs using bits and pieces that I found in the garage. This is the final prototype before I begin proper construction. This prototype is built out of 2 leftover planks of laminate flooring and an old curtain pole. Its not some new "suburban" take on a starwars yoke, just what I had avaliable. I dremmelled out the spurs and have attached them to brass rings. The rings are then attached to the hollow pole and pinned in place using 2mm bolts. The brass rings will also add support for the center springs when I can find some.

Although made entirely outta junk its shaping up nice!

(http://forum.arcadecontrols.com/index.php?action=dlattach;topic=51525.0;attach=93566;image)

Now onto the reason for the post. Before I can start Episode 4 (The beginning!) I need some technical help. Im using a Dual strike usb hack to interface this to "BubbleGum Betty". My problem surrounds the required "pots". Everything I have read implies that I need 5K pots that have a 270 degree turn. I cant find these things anywhere! Can they be substituted for another ohm of pot with 300 degrees? Why 5K pots is this all that the Dual strike can handle. Once this is sorted out I can begin full construction. HELP ME OBI_WAN KENOBI YOUR MY ONLY HOPE!

Im also looking for transparent hand grips, If anyone knows where I can find some or has a couple of old transparent joysticks let me know.

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: Neverending Project on January 21, 2008, 11:57:37 am

Could you use these pots (http://www.happcontrols.com/joysticks/50206400.htm)? Specifically, the 5K standard (don't use an S-Taper).

Also, if you use a larger pot but with limited range, this would accomplish the same net range. In other words, say you found a 300-degree 20K pot. The full range of motion of the pot would be between 0kOhm and 20KOhm. But if you restrict it's movement so you can only turn it +/- 45-degrees (90-degree total range, as an example), then you will effectively be getting between 0KOhms and 6Kohms resistance (90 degrees is a little less than a third of 300 degrees). Likewise, a 10-turn 300KOhm pot when restricted to 90-degrees will have a net range of about 7.5KOhms.

What pots are you able to find?

Hope this helps...

Also, here (http://www.mouser.com/search/Refine.aspx?Ne=254357+1447464&N=254357+1323038&Ns=P_SField) is a large selection of pots, FWIW.

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: waveryder on January 21, 2008, 01:16:01 pm

I am based in the UK, so delivery is a bugger. I can get 4K7ohm pots or 10k, 20K, etc really easily but no 5K linears for some reason. They all have 300degrees of rotation, the yoke will have bumbers (like the original) to restrict its movements anyway. This could work out as an ideal solution.

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: NickG on January 21, 2008, 03:33:42 pm

if you really need exactly 5KΩ over exactly 270°, then you can use a 10KΩ 300° pot in parallel with a 12.5KΩ resistor.  For the 12.5KΩ you can dial a 15KΩ variable resistor down to 12.5KΩ.  This way, you can calibrate the full range of the yoke with the variable resistor.   

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: Neverending Project on January 21, 2008, 04:26:10 pm

Another thought... for a yoke, how will you get 270° travel? I can understand for a steering wheel game, but I can't imagine turning a yoke from left-to-right more than about 90°, or twisting the grips front-to-back more than 90° either.

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: shardian on January 21, 2008, 04:31:32 pm

Maybe I am lost, but what does it matter if you have physically restricted the stick? You can calibrate the max range of the joystick in windows anyways.

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: NoOne=NBA= on January 21, 2008, 06:38:49 pm

Quote from: Neverending Project on January 21, 2008, 04:26:10 pm

Another thought... for a yoke, how will you get 270° travel?

The originals use a drive gear on both pots that is smaller than the gear hooked to the axis.
This increases the amount of travel on the pot relative to the actual movement of the yoke.

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: ark_ader on January 21, 2008, 09:25:32 pm

Why bother with the pots. 

Use a mouse hack.   

Its easier and quicker like the Dark Side.......

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: waveryder on January 22, 2008, 03:00:38 am

I have a smaller gear for that will be mounted on the pot. The gear ratio is 2:1. This is where my confusion about the required pot comes in. The full 270degs will be used but the yokes travel will only be 90degs across each axis (+/- 45 each way) thats where my confusion about the required pot comes in. I have done a little more research and have found that on amp building forums people are using 4K7 linear pots to replace 5K's as the tolerance makes them essentially the same thing. Can anyone enlighten me on that? ark_ader Yes the dark side is more seductive.........but the DS hack will be used to interface a lot of other analogue controls as im changing my cabs control system to "Hot swap" metal panels. The yoke is the first of hopefully many.

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: Minwah on January 22, 2008, 10:19:32 am

Quote from: ark_ader on January 21, 2008, 09:25:32 pm

Why bother with the pots. 

Use a mouse hack.   

Its easier and quicker like the Dark Side.......

I don't think it will work as the controller is restricted, it will lose calibration easily.  Someone beginning with 'J' (IIRC) made one like this years ago...it looked sweet but he commented that he should have used pots!

I think you could use 5k pots as someone else suggested.  As long as they rotate a reasonable amount then as someone else said you can calibrate in Windows.

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: Beley on January 22, 2008, 07:57:28 pm

Quote from: waveryder on January 22, 2008, 03:00:38 am

......I have done a little more research and have found that on amp building forums people are using 4K7 linear pots to replace 5K's as the tolerance makes them essentially the same thing. Can anyone enlighten me on that? ........

A 5kohm pot with a 10% tolerance (most are 10-20%) could be anywhere from  4.5k to a 5.5k
A 4.7kohm pot with a 10% tolerance could be anywhere from a 4.23k to a 5.17k

as you can see its quite possable to buy a 4.7k and a 5k and have the 4.7k pot have a higher resistance then the "bigger" 5k pot

the actual difference between a 5k and a 4.7 is only ~1%, significantly less then the tolerance

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: waveryder on January 23, 2008, 05:31:10 am

Surely then that ~1% can compensated for by the Dual Strikes/mame's configuration.

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: waveryder on January 24, 2008, 07:37:27 am

Started playing with the DS pcb today and measured the existing pot. Its a 20K, the sidewinder is restricted by a plastic stopper from turning very far so it never uses all of the pots turn. I have played around with the settings using just the estimated 4k7 pot turn and it works perfectly and Ive managed to have a quick game of starwars. Now to get on with the final build.

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: jukingeo on December 10, 2008, 09:02:42 am

Quote from: waveryder on January 24, 2008, 07:37:27 am

Started playing with the DS pcb today and measured the existing pot. Its a 20K, the sidewinder is restricted by a plastic stopper from turning very far so it never uses all of the pots turn. I have played around with the settings using just the estimated 4k7 pot turn and it works perfectly and Ive managed to have a quick game of starwars. Now to get on with the final build.

Which version of Star Wars is this?

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: SavannahLion on December 10, 2008, 01:15:38 pm

Quote from: NickG on January 21, 2008, 03:33:42 pm

if you really need exactly 5KΩ over exactly 270°, then you can use a 10KΩ 300° pot in parallel with a 12.5KΩ resistor.  For the 12.5KΩ you can dial a 15KΩ variable resistor down to 12.5KΩ.  This way, you can calibrate the full range of the yoke with the variable resistor.  

I think I'm doing my math wrong. I figure 10KΩ 300° restricted to 270° amounts to a 9KΩ pot. If one wants 5KΩ out of that, I figure ~11.1K would be the resistor to use. Am I missing something?

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: Todd H on December 10, 2008, 01:35:36 pm

Quote from: jukingeo on December 10, 2008, 09:02:42 am

Which version of Star Wars is this?

http://www.minionsoft.com/

Title: Re: Can't Bullseye Womprats In My T16!!
Post by: HaRuMaN on December 10, 2008, 03:23:37 pm

Quote from: SavannahLion on December 10, 2008, 01:15:38 pm

Quote from: NickG on January 21, 2008, 03:33:42 pm

if you really need exactly 5KΩ over exactly 270°, then you can use a 10KΩ 300° pot in parallel with a 12.5KΩ resistor.  For the 12.5KΩ you can dial a 15KΩ variable resistor down to 12.5KΩ.  This way, you can calibrate the full range of the yoke with the variable resistor.  

I think I'm doing my math wrong. I figure 10KΩ 300° restricted to 270° amounts to a 9KΩ pot. If one wants 5KΩ out of that, I figure ~11.1K would be the resistor to use. Am I missing something?

SavannahLion, your math is correct.  ( 1 / R ) = ( 1 / R1 ) + ( 1 / R2 )...