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Servo Controlled Choke


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#1 Stevelee10

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Posted 31 March 2015 - 08:32 PM

thought i would stick this in here in case anyone is interested in my little project. its pretty simple and i think might work quite well.

 

i decided i didnt like the push pull heater and choke controls so decided to make something nicer so im now going to be fitting some nice knurled chromed knobs instead. and ill now be using power servos to control the clutch and heater. i made some developments with my idea today and actually tested it on the choke, just need to beef up the power supply a bit, 4.8v just doesnt cut it. the servo only has 10.4kg/[email protected] but at 6v its 12.8kg/cm which should work spot on. just need to refine it a little and do the same for the heater then mount the 2 potentiometers on the dash in place of the push pulls and get some knobs. i was looking at these ones http://www.ebay.co.u...=STRK:MEBIDX:IT

 

open to constructive criticism or any input people may have

 

 

20150331_200153_zps9bauqml1.jpg

 

20150331_200203_zps8rk4vbxl.jpg

 

 



#2 lawrence

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Posted 31 March 2015 - 08:39 PM

I like that :) needs a nice bracket other than a cable tie but for a first effort it's a great idea

I myself was thinking that the other day how I should look into removing the choke,
Am thinking of using a megajolt output to control a relay that controls a servo

Where did you get your servo from?

Lawrence

#3 Harrison541

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Posted 31 March 2015 - 08:47 PM

Thats one more Tshirt you can hang up with that saved peg! Id love to see a vid of this working



#4 Stevelee10

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Posted 31 March 2015 - 08:52 PM

its from the local model shop, has to be a power servo i tried a standard servo the first time it couldnt even move anything. you will need more than just the relay to operate the servo, they work using pulse width modulation, so ive controlled my servos with an arduino uno board and a potentiometer.

this is the servo im using, there £19.99 http://alturn-usa.co...s/AAS-750MG.htm

i agree i need to make a nice bracket for it, im also thinking of developing it further and adding a switch so i have the option of making it automatic by taking a signal from the water temperature sensor.



#5 Stevelee10

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Posted 31 March 2015 - 08:54 PM

heres a video, its a little slow as its only running on 4.8v but im gonna use a voltage regulator to give it 6v

 



#6 Spiffingly Good

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Posted 31 March 2015 - 08:58 PM

You could also consider removing the spring from the choke mechanism as the servo works both ways, and the spring is mainly in aiding the choke cable to return.



#7 Shifty

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Posted 31 March 2015 - 09:08 PM

Next up would linking the servo to the temp sender so it progressively reduced the amount of choke as the engine temp increases.



#8 Stevelee10

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Posted 31 March 2015 - 09:27 PM

Next up would linking the servo to the temp sender so it progressively reduced the amount of choke as the engine temp increases.

 

yeah ive been thinking about doing that and removing the choke control completely.

 

You could also consider removing the spring from the choke mechanism as the servo works both ways, and the spring is mainly in aiding the choke cable to return.

 

i tried it without the spring but i found it returned better with it. however if i find upping the voltage doesnt sort the speed out i will remove the spring



#9 fenghuang

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Posted 31 March 2015 - 09:45 PM

I'm curious what advantage retaining the return spring has. The servo acts in both directions, and IIRC there is no significant force needed to move the choke arm on the carb if you remove the spring. If you keep it, aren't you just increasing the load on the servo?

#10 Stevelee10

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Posted 31 March 2015 - 10:24 PM

ill try without it tomorrow and report back


Edited by Stevelee10, 31 March 2015 - 10:25 PM.


#11 Stevelee10

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Posted 01 April 2015 - 08:35 PM

UPDATE, attempted to map the temp sensor tonight but it seems whilst ive been playing with the choke ive managed to kink the little fuel pipe on the jet and cant start the engine, so stuck till i fix that

 ::(



#12 Stevelee10

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Posted 10 May 2015 - 07:37 PM

Update. All electronics sorted an choke working well. Just need to make the servo mount more solid and set a limit on the servo
https://youtu.be/giqR1sMKhu8

Edited by Stevelee10, 10 May 2015 - 07:38 PM.


#13 peter-b

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Posted 10 May 2015 - 10:01 PM

What about an AED unit out of old series 2 XJ6?

#14 fenghuang

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Posted 11 May 2015 - 01:23 PM

Awesome.

I want one.

Though I might just make a servo controller circuit in the short term. (I'm sure I've got a 555 kicking around somewhere ... and even if I haven't they're a tad cheaper than an Arduino  ;-) )

 

The servo itself is moving and looks like it might foul on the air filter: have you got anywhere with plans for a different bracket?

Do you need to limit the travel, either mechanically or electronically?
Am I right in thinking that's a HS4?

Any thoughts on the temp feedback circuit yet?

You mentioned servo control for the heater valve as well. Are you any closer on that? (Presumably it will be exactly the same, technically, just a different mounting?)

What's your shoe size?

Sorry that last question wasn't strictly relevant but I was on a roll ...


Edited by fenghuang, 11 May 2015 - 01:24 PM.


#15 finch661

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Posted 11 May 2015 - 02:15 PM

this is amazing! I considered this a few years ago when i seemed to knacker a new choke cable within a few days. Never got this far. What about the possible issue of melting?

could you not used something like a heater cable (in terms of thinkness/stiffness) and put the servo inside the cabin, and have it control the cable (for the carb)?


Edited by finch661, 11 May 2015 - 02:15 PM.





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