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ASmartMan

G&K cruise control (Aftermarket)

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Howdy All :wooo:

I realized not long after I bought my G&K Smart that I wanted cruise control. I did the normal search through the threads (UK, Ca, Au, etc) and found there were 2 options.

OEM (Smart) cruise with an OEM stock BUT needed a TAN code up loaded, WELL being in the US and 3,500 miles away from Eddy (I asked if I could send him the module to program, he said he couldn't). The other option used the OEM stock that talked to a MDC electronics board, BUT at almost $500 I ruled that out.

Electronics is my job, so I started to make test points and take some measurements while driving, when I pulled out my Oscope to ensure I wasn't missing something I had a :wtf2: moment. I thought to myself "why was I reinventing the wheel, there are plenty of aftermarket cruise controls out there".

I searched the various threads looking for someone who used an aftermarket cruise control and much to my dismay I didn't find a one. I first thought to myself "Crap this can't be done", but soon realised IT CAN BE DONE.

Anyways, I just received this aftermarket cruise control http://www.brandsplace.com/0002-ccs100.html and I believe this can be done (I'm on vacation next week so I'll have the time to work out the details). My plan is to have it move the gas peddle (seeing there is NO throttle body to speak of).

The point of this post is to find out if anyone else has an interest in this, if so I'll make a point of taking pictures and doing some detail work I wasn't planing on, then post the project.

Wish me luck

ASM

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Interesting... looks like a vacuum cruise control so does not apply to the diesel.B:sun:

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No no - a vacuum system wouldn't work at all on the smart! The throttle is completely electronic. The engine is essentially mechanically isolated from the rest of the car, save the wheels!-Iain

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Hee Hee Hee :watchout: Remember, I am from the USA, and I have the G&K converted Smart car (USA= GAS).Now with that said, there is PLENTY vacuum available for me to use (get real, would I have made this post unless I knew it would work, DOH).Regardless, in my brain it should work and I should be able to make it work (still planning on the placement of the vacuum servo).And as far as the 451's are concerned, you are on your own, I am modifying a 450 and will ONLY offer insight to these cars ( chances are this would work on a 451 BUT I DON'T know for sure)I'm happy to see there is some interest here, that means I get to take some PICTURES :lol: I'll kep U All up to date as things go alongASM

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I have installed these units on many cars with no problems. I currently have one on my Dodge pick up with a Cummins diesel. I used the factory switches on the steering wheel and mounted the servo on the factoty mount. the Audiovox electronics are much cheaper than the factory units.It will be interesting how the vacuum is affected by the turbo on the smart. I haven't looked at it but I wonder what kind of vacuum exists at highway speeds with the turbo boost. That is when the servo is working hardest to keep the throttle open.Mounting the servo will be fun, not much room up front. I guess you can get creative with cable and pullys from r/c cars.By the way Audiovox used to make this unit with an electric servo for cars without vacuum like diesels. I don't know if they still make it.Good luck and have fun.

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I really really really doubt it will work... at least well and safely, but have fun. But I think you wasted your money.Still, even if it works (and I doubt it will) it will ultimately look like what it is designed as - a hack. $500 for the MDC version is because it looks, and for all intents and purposes is, factory cruise.Generic cruise controls have been around for a long time and are a suitable substitute in many cars that have generic looking dashes and controls anyway. This won't fit in with the look and feel of the smart in any sense. Beyond that... since the system has no direct knowledge of the vehicle's speed, its pretty unlikely you'll get a smooth ride (if you do get it to work at all)... the MDC reads the vehicle speed (among other things) and makes near instantaneous adjustments and sends the signal to the car's computer. This thing attempts to hold the pedal steady based on engine vaccuum... a primitive cruise method and if anyone remembers the earlier cars where you were either gunning it full speed or coasting to maintain a certain velocity... well, you'll get some ugly representation of that.Bottom line... I fear your post might have some people thinking they are spending a lot of money on a real cruise control when they could be spending only $100 on a generic one and get largely the same thing... and I honestly think that's not the case. There is form and function, but also ease of installation, and frankly safety, to consider. SPENDING five hundred is a lot better than wasting one.But, by all means... best of luck to you. - Steven

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Hey All

Well thanks to smartie yank I did some vacuum measurements this evening, and got a few surprises.

First, never having a turbo car before, it never crossed my mind that the intake manifold would go above 0" Hg, but with a turbo it does (I actually went up to about 6-8 PSI while accelerating), and at speed of 60 MPH I was only getting 5" Hg.

So it seems using a vacuum servo is not the way to go, or at least now it doesn't, I have a few options that I will research tonight but this project is far from dead.

Just so there is no confusion, I love to tinker, share my results GOOD or BAD, I am not advocating anyone do what I do. I'm playing with my new toy and sharing what I discover, and on another note. I am a 49 year old man who has worked in electronics since I was 18 and I do a pretty good job at it, SO don't assume just because I'm going a different route that it will be unsafe and look like a hack job, because it won't.

I possess the skill needed to design a circuit to emulate the the gas peddle and there are MANY signals I could use to measure speed, OOHH and I could even use the Smart stalk as part of the design. BUT just how many people would enjoy (or be able to follow) that post as I talk about comparator amps, D to A converters and programing a PIC chip.

On the ECU unit, Transmission speed it on Pins 11 (Red) and 30 (White), this is a square wave pulse (Hall effect sensor) who's duration gets smaller but frequency increases as you speed up.

Crankshaft RPM (Tach) is on pins 8 and 9 (both are red), once again another square wave.

all this data is here http://evilution.co.uk/index.php?page=modpage

Where Audiovox cruise controls have been out for ever and have a VERY good reputation, I felt very comfortable using this (safety and appearance wise), If I end up not being able to use this model on my Smart, it will go on my wife's car (she is already excited and hope my efforts fail, WHY, I don't know, she drives 30 mile a week).

I will be exploring and axillary vacuum pump (the kind used for when you convert your car to all electric but have power brakes) and search for a electronic servo cruise control, I should be deciding on the next step by tomorrow (again cost will be the motivator). I'll keep you informed.

Well that's it for 1 night

ASM

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I see in your signature you have a 'trip computer' also on the horizon. How so? If I recall, only the MDC works on the G&K cars. Curious.

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smartzuu

Let me get this first project out of the way before I start talking about the trip computer :magic:

All

Well it was a very short search, when a good onboard 12 volt vacuum pump came out at $300 + I decided the wife is getting cruise control and I just bought this http://www.audioallies.com/GetItem.asp?Item=2501316 for about $180. It will be here Tue (Monday is a holiday in the US).

We'll restart the games on Tuesday :banghead:

ASM

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Could be an expensive cruise control after all, I mean, the one in your wife's vehicle.;-)

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I find that the ScanGauge is a fine trip computer. Plus I read an error code (unstable idle speed) on my friend's Nissan Altima when in Vancouver Wednesday night!I agree with Steven, pay the money and get properly integrated cruise. It's slightly cheaper in US $ ;)

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Or Build your Own! Viva la Invention! And the spirit to do things - just because you can! As the saying goes - "Open your mind"!If you need any wiring circuits etc. - PM me - I might have a source. If you have an electronics back ground the more elegant approach might be to tap into the gas pedal circuit - it is basically a POT - you just provide the right signal an the throttle opens accordingly out back - this is how the MDC one works - you stick a circuit board inline with the pedal cable and hook up another cable to the switch and the speed circuit (there is a output on the back of the instrument panel) and another to the CAN Bus for the signal from the brakes etc.So basically you need a circuit that reads the set speed - and adusts the gain of the pedal signal to make the car's speed up or down to match. If you have any expereince with PIC or other micro computers it could make a fun project - couple other inputs have to be captured - possibly from the CAN Bus or other sources.The stalk controller for the smart basically is two switches - one a momentary contact - cruise on - cruise off - the other is a momentary contact two position - one way to increase other way to decrease - nothing special. Cheers,Cameron

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I find that using the cruise for an hour and then switching to the limiter for a while is good for the right foot.....gives it something to do! It's the best value for money I have spent on the car since the strikelines.

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Mike T unfortunately the scan gauge doesn't work in a G&K smart.ASM that is the electronic unit I was talking about. I'm sure it will not be to difficult to find a source to read the speed. I put one on a Peugeot diesel years ago when you epoxyed 2 magnets to the drive shaft and mounted a pick up coil next to them. The Peugeot had an enclosed driveshaft so this was out. I mounted the magnets on the A/C compresser pulley and it worked great. The car had a standard trans so the engine speed was constant to the driveshaft, no slipping torque converter. There were other units that picked up a pulse from the ignition coil. Lots of posibilities.Mounting the electronic control servo can be fun and very creative. Small cables and pulleys can be hidden in many places. Have fun :doublethumb:

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I will see if I can find the connector on the back of the instrument panel - it feeds a speed signal if I recall correctly - think Duck was playing with this when he had issues with his speedometer or something.Cheers,Cameron

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I'm wondering how ASM is coming with his project. I finally "bit the bullet" and got the MDC unit - planning some longer trips again in the next few months and decided I was not going to go another 3k-4k miles without it. I'm not quite getting the 1km up or down that I've seen reported for the OEM; but it works quite well during the 700 miles I've put on so far. There's just one thing that has me puzzled - in manual mode with cruise on it has downshifted from 6th to 4th 3x when going up a rather slight incline. (Don't have a tach but it sounds like the engine rev'd up quite high.) In the auto mode it seems to just shift down 1 gear.

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The MDC cruise downshifts for you when the car is in manual mode?The OEM type doesn't, so you have to do it yourself, unless the car is in softouch.

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The MDC cruise control doesn't shift at all folks.The car does the shifting, the cruise control simulates your right foot - that's all.So if you are going from 6th to 4th, then it can't have been that slight of an incline! What is happening, is that your rpms go SO low that the car (not the cruise) forces a down shift. Just like when you are coming to a stop, the car will automatically shift down to 1st if you didn't do it yourself. Same thing. Its the car doing the shifting.To be clear... in the smart, if you drive in "manual" mode and NEVER touch the shifter, the car will still shift for you, both up and down. You probably shouldn't do this, because on up shifts it waits till redline and on downshifts it waits till near-stall... but the car won't let you over or under rev. In "automatic" mode, it does the same thing, just with more logic resulting in better shift points. In either case, it has nothing to do with the cruise control. - Steven

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The stalk controller for the smart basically is two switches - one a momentary contact - cruise on - cruise off - the other is a momentary contact two position - one way to increase other way to decrease - nothing special.

That's a LITTLE simplistic, don't you think? "nothing special"... to make one yourself that is identical, it would cost you probably $250,000+ in design and tooling costs. Ok, the second one would only be about $10... but that first one's a doozie.I get what you're saying... the electro-mechanics of it is conceptually simple. However, aesthetic value means something too. To make that same look, feel, and function on your own.... practically impossible.While I understand inventive desire.... and cheapness... and a want to "stick it to the man"... no matter what comes of this experiment, its going to look and probably feel like a hack job to one degree or another. At best, its going to look like the early remote-version of the MDC if anyone remembers those! It worked, sure... but... how would Duck put it? "Puke my freakin brains out!"hehe. - Steven

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The MDC cruise control doesn't shift at all folks.The car does the shifting, the cruise control simulates your right foot - that's all.So if you are going from 6th to 4th, then it can't have been that slight of an incline! What is happening, is that your rpms go SO low that the car (not the cruise) forces a down shift. Just like when you are coming to a stop, the car will automatically shift down to 1st if you didn't do it yourself. Same thing. Its the car doing the shifting.To be clear... in the smart, if you drive in "manual" mode and NEVER touch the shifter, the car will still shift for you, both up and down. You probably shouldn't do this, because on up shifts it waits till redline and on downshifts it waits till near-stall... but the car won't let you over or under rev. In "automatic" mode, it does the same thing, just with more logic resulting in better shift points. In either case, it has nothing to do with the cruise control. - Steven

thanks for the info...that helps...ps I love my cruise control!!

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The issue here is the the gas engine revs much higher than the diesel. Like Steven said the car does the shifting not the cruise control. In the hills at highway speeds the gas will drop 2 gears while the diesel will only drop 1 gear in the same conditions. The torque is similar in the 2 engines just made at different rpm. If the car is slowing down the cruise will keep the throttle wide open and the revs at redline trying to reach the preset speed. Again the computer will not let the engine hurt itself.

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Hey All About a week and a half ago I jammed 2 fingers and kind of was put out of commission, I plan to restart this project tomorrow. I was also slowed down by some software installation, and this is still an ongoing project.I’m confused why it will be assumed this will be a hack job, I have 3 options for the controls, 1: buy an OEM stock and wire it in to the after market C/C, 2 use a miniature membrane switch pad affixed next to the shifter, or 3 buy the OEM cabrio soft top control panel (this may be the option I go with because this is a natural hand location while driving, requiring very little movement to adjust speed).I should have this mechanically installed before the end of the weekend, would U guys like to see it as the steps are completed or just 1 big project report.Later All ASM

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