Designing a replacement cruise amp - Page 3 - PeachParts Mercedes-Benz Forum

bgkast · #31 05-28-2008, 04:24 PM

Quote:

Originally Posted by ConnClark

I thought I might chime in on this thread. Since I now work for a company that assembles, designs, and consults on PCBs I thought I would put in a shameless plug for our services in case you want to do volume production on a prebuilt version.

http://www.njc.com

You probably won't deal with me directly though.

Glad to hear you got a new gig. You should make some electronic VNT control circuitry.

techguy512 · #32 07-01-2008, 07:44 PM

Quote:

Originally Posted by 300SD81

I thought I might give making a modernized cruise amp a try

So how's the project coming along?

300SD81 · #33 07-01-2008, 07:54 PM

Quote:

Originally Posted by techguy512

So how's the project coming along?

Its on hold until I get my new car, the current Benz is in permanent storage in my garage for the next few years, going to pick up the new one this Sunday. I've got a good bit of the software done, and a basic design of the hardware. Still trying to figure out how to feed the speed into the microcontroller, probably have to load my 50lb vacuum tube oscilloscope into the car and go for a drive...

a2t · #34 07-02-2008, 11:35 AM

From my chats with GDL, the speed signal isnt "normal". He said he has only ever seen it in on Benz cruise control systems. Some kind of modified square wave. Go figure.

Once you load that oscilliscope, you're gonna look like the prop car from Back to Future. Which is excactly how any aspiring EE student's car should look

Good luck and keep us posted. This is real world learning, not text book stuff. So much more valuable.

Just make sure the thing cuts off when you touch the brake pedal, or remember to go key off if things get out of hand...

rhodes2010 · #35 07-02-2008, 01:18 PM

A newly designed unit will support all of us into the future.
A redesigned but functional unit that can be serviced by us as needed is perfect.

I repair PCB based things all the time and am reminded that this is a lost art.

For me, I would really, really appreciate someone applying this to the earlier
10 pin unit like my 1980 (and 1981) 300D's have.

Even a suggested replacement parts guide with how to on testing
would be very valuable. It cannot be that hard.

I have done the board re-solder and it still is not 100 percent.
Would prefer a parts list and guide, like we have on the dashboard clock.

CoyoteStarfish · #36 07-02-2008, 09:35 PM

I'd buy one. Especially if you could modulate cruise stalk inputs to activate presets somehow.

Like resume x1 from a stop takes you to 30MPH
Resume x2 = 50MPH
Resume x3 = 70MPH

Or make it a user setting by multiplier jumpers in the housing.

Also being able to control engine idle, and LOCK it in at a standstill would work great for warmups (high idle?) or other diagnostic/tuning procedures.

CoyoteStarfish · #37 07-04-2008, 04:49 AM

You know, with some time to think about it.. Simply raising the speed in increments of 10MPH would be better

turbobenz · #38 07-04-2008, 05:01 AM

as for durability Ive always encased my pcb's in epoxy. This seems to make them completely bomb proof. But if a component burns out then your done.

Tymbrymi · #39 07-04-2008, 06:57 PM

Quote:

Originally Posted by CoyoteStarfish

I'd buy one. Especially if you could modulate cruise stalk inputs to activate presets somehow.

Like resume x1 from a stop takes you to 30MPH
Resume x2 = 50MPH
Resume x3 = 70MPH

That would drive me nuts, and is probably unsafe.

Quote:

Originally Posted by CoyoteStarfish

Also being able to control engine idle, and LOCK it in at a standstill would work great for warmups (high idle?) or other diagnostic/tuning procedures.

The electronic (not sure about vacuum... I've used the electronic ones in other applications and they were great) cruise actuators are pretty accurate, and I would trust them to regulate the engine at idle level speeds (a super slight movement in throttle results in huge RPM changes). The only problem is the throttle linkages. With as much slop that is in them (even in a perfectly functioning one) it would probably make this near impossible.

Quote:

Originally Posted by CoyoteStarfish

You know, with some time to think about it.. Simply raising the speed in increments of 10MPH would be better

I think 1mph is plenty. My CDI has that... and I can change the set cruise speed 10mph higher in about a second (10 quick taps). It also has a digital display... so without that it might take a little longer since you don't have the super quick feedback.

Just my $.02