It's rare that I have any concern over safety but in this case having a homemade circuit that bybpasses the gas pedal just because you are cheap and a lazy driver seems like all around stupid and unsafe idea.

hmm... little harsh i think. hasn't cruise control stemmed from people's laziness to begin with? just like the adaptive cruise control and now automatic brakes because people don't know how to pay attention when they drive? I see what your saying but no one experiments and learns anything anymore.

monitoring your speed in this case would require more attention than just setting a speed and forgetting about it. this isn't for driving through towns or anything like that. I never intended to compromise safety. It would have to disengage after hitting the brake or else i wouldn't use it... this is even assuming it would work to begin with. if i really wanted to compromise safety, i would just put a brick on the floor to hold the pedal in place.

 

here are the 'instructions' sent to me from one of the companies for how to install their system. just to give you an idea of what I am working with and why I am worried about all the cut's and splices they want to do.

if I built something on my own, I would get all the stock connectors and build a nice harness that would allow me to simply unplug... and the same if I used one of their systems.

 

I see what your saying but no one experiments and learns anything anymore.

I experiment and learn constantly, much of it with dangerous to potentially deadly capacities as well, hence but at some point I draw the line at whats practical and rational for a person to handle which as you admit your electronics knowledge and skill are not anywhere near the top end of things.

That and there is a difference between experimenting with something that can kill me Vs something that can malfunction and potentially kill others is in play which is what you are working with.

Given the drive by wire tech in your vehicle largely depends on a simple voltage signal to tell the vehicle to go if the system ever malfunctions and sends a false high signal out the engine goes full throttle.

Now an event like that happening on an open highway is manageable given the open spaces and time lag based on how fast the vehicle can possibly accelerate. However if it does that at a busy intersection where you have crowd of people on a cross walk a few feet in front of you you will never be able to gain control fast enough. Therein lies just one part the realistic problem.

Making a cruise control that is safe is not as simple as adding a bypass to the gas pedal.

I'm ll for lazy but not potentially dangerous to others by my own too cheap to work properly creations lazy.

That and it looks like the gas pedal is not just a simple variable voltage based systems but a complex multi sigal rotary encoder based one.

http://www.autocodes.com/p2135_2007_ford_fusion.html

Oh yea and your voting window should also include.
'Dangerous control systems hack,'
as a third choice.

 

Take a close look at your solution and try to imagine a scenario where your circuit could fail and does take action to avoid an injury. Repeat the process and identify those scenarios where it could cause injury/damage and fails. Then, put it aside and buy an aftermarket solution, because the probability that you missed a critical scenario is 100%.

 

In a properly designed cruise contorl there is a safety tie in related to vehicle speed where it can not be activated under 25 - 35 MPH which on a modern vehicle would be a safety circuit that would be near impossible to add without having substantial knowledge of how your exact vehicle electrical and electronics systems work.

If you really want cruize control you would be time money and safety ahead to just find the factory components form another vehicle and install them in yours being the modern cruise control interface buttons are not just simple momentary contacts like itne older systems that send a High/Low signal to the ECM but are part of a dedicated CAN buss control systems sub circuit that interfaces the button signals to the actual ECM. similar to how the gas pedal is not just a potentiometer that puts out a variable voltage signal.

A bit more info on what you would be working with. It's complicated.

http://openxcplatform.com/

 

@1point9turbo

If you are skilled with soldering iron, why do you include the price of installation when you do the make-vs-buy analysis? Install it yourself. Now the total cost is 350, safe, works well and likely doesn't have to be explained to insurance agent after an accident.

 

yeah, im just not too keen on cutting and soldering the factory wires. Id rather use connectors and be able to remove it. most of the systems seem to have factory connections for the petrol cars but you are on your own for the diesel ones.

i appreciate everyone's input.