Arduino powered taillight project.

[Tomcio]

Fairly sure. I had Rob Grady take a look at it at one point, although that was quite a while ago now (2-3 years), and my local shop about a year and a half ago. The system was bled each time, and it didn't appear to be leaking. I'm not sure it's worth checking this out now since the car hasn't run for a year, but I'm guessing I could push the brake pedal and see if anything odd is going on.

Some leaks might be very difficult to see. I remember when I once spent an entire week trying to figure out why the brakes on my friend's car were soft and spongy. After checking everything (almost) and replacing the master I found that one soft rubber hose had a balloon where the fluid would go between the layers of the hose. It was in a spot where you couldn't see it. I found it by running my hand along the full length of the hose.

The car does have a Saag 50/50 master cylinder in it, if that matters.

Doesn't matter. It makes braking a bit less predictable when braking hard in a turn and you might end up spinning but in this case it doesn't matter.

the pedal was soft on the first pump, and firm on the second. This would happen basically every time I braked

What really matters here is if this soft pedal would appear even when the car was not moving.
If you pump the brakes, get a firm pedal, wait a minute or two and then the pedal is soft again but the car wasn't moving then the problem is in the hydraulic system. If it doesn't happen with the car stationary but does when moving then it's the rotors.

Ah, I didn't know that -- I'd only heard of warped rotors before, not of high spots from melted pads.

The reality is that in order to warp the rotor you would need to hit it from the side hard enough to deform the metal but not hard enough to cause it to crack. A good way would be to slide the car sideways and hit a curb hard enough to break the rim into pieces and hit the ground with the rotor. Sounds like fun
In normal operation the rotor is supported in the center with the pads pressing on it from both sides. Now, even in extreme cases where one pad stops moving the other pad presses onto the rotor when it's turning. It might deform all the way around but not warp. After fixing the problem the brakes would function normally but you might see some uneven wear right after installing new pads. Something like this:
R DAY 1.jpg

would this kind of thing be visible the rotor, or is it subtle enough that to feel for it?

It usually is visible but to actually verify that it is bad enough to cause the problem you need mount the rotor on a lathe and measure the runout.
This is what the pad imprint looks like:
(following pictures were found using G and are used without permission, I hope the authors don't mind)
brake-pad-imprint.jpguser162950_pic17269_1293299807.jpg

In extreme cases, especially after using poor quality pads and driving hard it might get to a point where the high spots start really showing up on the rotor. Then it will look like this:

unevenpaddepositsarrow.jpg

I will be sure to check as soon as the car is roadworthy again. Thanks!

No problem Joe. Glad I can help.
Let me know if you need more help but I think that we should move this conversation to a new thread. This was suppose to be cool taillight project! Sorry for drifting off topic here.

[bttws]

jangell

I'm hugely interested in this. What aftermarket system were you thinking of using? I figured I was going to have to roll my own (and thus spend a lot of time learning machine vision and image processing stuff to detect road lines). I've always wanted to see car manufacturers have systems to detect the lines and make it hard to change lanes unless your turn signal was on, and nudge you into he lane if you start to drift out of it. I think some are actually starting to do this, too.

While I would like to build an emergency braking system into my car (my idea being that I'm going to hit something anyway, so the system would slam on the brakes faster than i could so I'd hit it slower; it's something I've been thinking about for more than a decade now, and some manufacturers are now doing something like it to avoid collisions entirely), I don't trust my programming skills enough to use them on critical systems that can get me killed. I don't want a leaf to fall onto a sensor and cause the car to slam on the brakes, for example, so it would require a huge amount of testing. I'd like ABS too, but I won't do it for the same reason, unless I can get a complete aftermarket kit.

It's called the Mobileye , I've seen some reviews and it seem to work just like modern cars. I would most likely tear then thing apart and figure out how to send the data to a computer. It runs about $850 so I would differently need to learn a lot more before I fry the thing.
http://us.mobileye.com/mobileye-560/

[bttws]

New parts have arrived.

I pluged my taillight into the example board and ran some test code (mostly to test brightness) The display is a little crazy, the board is designed for a 8x8 matrix. My setup is 6x13, so I with have to make a new circuit, but this is a good jumping off point.
I'll work on it this weekend.

Kevin

[robvanderveer]

I could make a desk version.... Maybe I should do that first. I could have it display network status or something. Maybe a audio visual or some kind of clock....

Bluetooth connection with a smart phone is possible.

May I point you to my 'Aduro' project for Arduino/Mac. It drives a bluetooth(serial) enabled ledstrip. If you need help with the code, give me a shout.

[bttws]

May I point you to my 'Aduro' project for Arduino/Mac. It drives a bluetooth(serial) enabled ledstrip. If you need help with the code, give me a shout.

Looks awesome. I will be contacting you when I get to the coding part. I have just started learning and have to say, I'm not very good at it. I could defiantly need help. Thank you!

[robvanderveer]

no problem! the offer stands!

[Shep]

Looks awesome. I will be contacting you when I get to the coding part. I have just started learning and have to say, I'm not very good at it. I could defiantly need help. Thank you!

10+ years of coding experience talking here: Although I haven't seen the source code (nor would I ask for it), I can say that the end result is spectacular! I got my start coding desktop systems, and only in the past year or two delved into electronics via Arduinos. Let me be blunt: I could learn quite a few things from YOU! The timing you have all those LED's going off in that first post, and the direction with the 8x8 matrix chip and all, let me just say I'm quite impressed with how swank it all looks! I'm going to see what I can make of my own taillights as a one-off project, but man alive I'm extremely glad you showed us this and gave me an actual useful purpose for them!

[robvanderveer]

10+ years of coding experience talking here: Although I haven't seen the source code (nor would I ask for it), I can say that the end result is spectacular! I got my start coding desktop systems, and only in the past year or two delved into electronics via Arduinos. Let me be blunt: I could learn quite a few things from YOU! The timing you have all those LED's going off in that first post, and the direction with the 8x8 matrix chip and all, let me just say I'm quite impressed with how swank it all looks! I'm going to see what I can make of my own taillights as a one-off project, but man alive I'm extremely glad you showed us this and gave me an actual useful purpose for them!

I don't want to sound disrespectful, but if you can't imagine how to drive an 8x8 matrix with a C library i'm wondering what you did those 10 years!

[Shep]

I don't want to sound disrespectful, but if you can't imagine how to drive an 8x8 matrix with a C library i'm wondering what you did those 10 years!

Everything except electronics Mostly C#.NET desktop web/database programming. Still gathering my bearings in the electronics world.

[jangell]

It's called the Mobileye , I've seen some reviews and it seem to work just like modern cars. I would most likely tear then thing apart and figure out how to send the data to a computer. It runs about $850 so I would differently need to learn a lot more before I fry the thing.
http://us.mobileye.com/mobileye-560/

That's pretty cool. I wonder why they require "professional installation". I am also interested on how to get data out of it and into a computer for my own purposes. I'm guessing they don't have an API for third party applications, or at least not one you can get if you're not an auto manufacturer...

Thanks for the link

-- Joe