76 project

[7TRoadster]

What ya been up to?

The gauges look good, you might consider dulling the LED's a bit. I put LED's for the nitrous controls behind dark plexiglass in my El Camino. I ended up pulling them and sanding the lenses with 1200 to dull them out. They were just too bright, even behind the dark covering.

Can you dim an LED? They use such a small amount of current to operate, I always thought they were an on or off deal. Never tried though...............

Keep us posted on what you decide.

[brent319]

If I am not mistaken led are pretty much off or on, but you can dim them a bit by adding more resistance in line. I am looking into a pulse width modulation dimmer for them. I have found some but not exactly what I want.
I keep seeing this one..

Amazon

Amazon

Anyone know if I am on the right track here or have suggestions?

[rtj]

You could always put a grey piece of glass ( neutral filter ) over them to cut down the intensity. If you have room. No electronics required (optics only).

[rtj]

Good work, that car will be worth the wait and effort.

[Curby]

Originally Posted by brent319

If I am not mistaken led are pretty much off or on, but you can dim them a bit by adding more resistance in line. I am looking into a pulse width modulation dimmer for them. I have found some but not exactly what I want.
I keep seeing this one..
http://www.amazon.com/LEDwholesalers.../dp/B003L4KKF2
Anyone know if I am on the right track here or have suggestions?

I think you are on the right track.

My LED flashlight has a bright mode and a dim mode.

[brent319]

I found a cheap PWM box on eBay that will control my LED's for about ten bucks with shipping.

I took it apart and as I was hoping, it looks like I can take the pot' out of the box, extend the wires a bit, and mount the knob in a good location with the box hidden.


The box seems to work well from full down to nothing so I should be able to make it work. (Click below for really bad video)



I may wind up painting the inside ring of the bezel a flat black so it does not get the glowing ring around it, although it is not nearly as bad as it looks in the video.

I am working on finding a time in January when I can go back out to SD and get some more work done on the car. I am getting to where I really want to have this thing home again. The plan is still to have it on the road this spring. I am sure it won't be totally done by then, but then again I don't think it ever will be "totally" done.

[7TRoadster]

Your usual outstanding work. I swiped one of your ideas and installed a MP3 player in place of the ashtray in my car too.

I'm sure you will be tempted to admire all the light candy while driving. I hope you don't get distracted so much watching where you're going becomes secondary.

[Curby]

Brent, that is awesome!

[Denpo]

Brent, concerning your dimmer, I'm on the same very path.
But I've found something quiet annoying.
Ok, at least on my dimmer, it has the exact same same casing, but the board inside has a different layout (but same design as far I can see).
On my dimmer, if you look at the back at the board you can see the two V+ connected. That means it's a sink design, shutting on/off the V- side of the circuit.
This means you can't use the ground of the car and need to wire V+ and V- down to each led.
Is that what you're doing?

I'm looking into making my own dimmer that could work with the car common ground and keep most of stock harness.

[brent319]

Wow. I did not look at the board other than to take it apart and see if the pot was soldered onto the board so I could relocate the pot if I wanted to
All I did was hook it up to a 12v battery charger and try it out. If it is modulating the negative side of the charge to the leds, would that not work in the car? I don't know as much about this stuff as I would like so I am not understanding why it is a problem.
Thanks for the reply.

[Denpo]

Originally Posted by brent319

Wow. I did not look at the board other than to take it apart and see if the pot was soldered onto the board so I could relocate the pot if I wanted to
All I did was hook it up to a 12v battery charger and try it out. If it is modulating the negative side of the charge to the leds, would that not work in the car? I don't know as much about this stuff as I would like so I am not understanding why it is a problem.
Thanks for the reply.

Maybe posting a pic of both side of your board could help checking your design is similar.
I'm gonna try today to tweak the dimmer to work on the positive side, I'll let you know.

[Denpo]

Originally Posted by Denpo

Maybe posting a pic of both side of your board could help checking your design is similar.
I'm gonna try today to tweak the dimmer to work on the positive side, I'll let you know.

Ok didn't work, but I've found this :
http://www.solorb.com/elect/pwm/pwm2/

See how each configuration use different switch transistor.

So we may need to replace the N-mosfets with P-mosfets.

[Denpo]

Hey Brent, I have been studying the dimmer problem with specialists on a electronic forum.
Our problem is not simple, dimming by switching the negative side il the way to go ("low-side switching" is the term)
When doing high side switching, the switching component takes the load and heat up (don't ask me why).
It's definitely doable, but component have to be sized according to the Amp the system behind is going to draw and adequate heatsink provided. In our case (interior led lighting) this shouldn't be a problem.

So I'm talking to these guys and will try to come up will a custom board design. If it works I'll make you one, I'm pretty sure we'll find a way for you to return me the favor.
I'll let you know.

One a side note, I also learned that as soon as you mention your design is going in a car they'll just stop answering you.

[brent319]

Denpo: I am still not sure why the dimmers won't work the way they are. The only thing I can think of is that maybe you want to run the + side from the box to the LED and then run the - to a chassis ground. I am just going to run the pos and neg into the box and run small pos and neg wires to the LED's. It is my understanding that all of the other switching done with the LS is done on the neg side. (low side switching?)
Anyway, I am quite a ways away from installing the dash, so I think it will work out by then. After all of the time I spent on the gauges, I am thinking about going with the Dakota Digital VHX gauges. I might be selling a full set of Autometers if that happens if anyone is interested. They have fancy turn signal indicators :-)
I am headed over to South Dakota to work on my car next weekend. I should be there for a week or longer depending upon how it goes and also the weather. I am hoping that we can get the front fenders on and the back end finished up. Ideally I can work on the custom hood I have in my brain. Nothing too radical, but a bit different.
The plan is still to have it on the road this spring. My 50th birthday is coming up in June and this would be a perfect mid life crisis... I mean celebration Also my wife "sidepipes" and I will be celebrating our 25 anniversary in May. She always said she wanted to go on a cruise. While I don't think this is what she meant, it would still be sweet to take a cruise in the 'vette.
I will post up some pictures in about a week.

[Marks76ray]

Hey Brent, my 50th birthday is in Febuary! Wish my Vette was ready for a cruise. But I do enjoy working on it and dreaming up what I want the finished car to look and drive like. I have several other projects planned after the Vette. One being a teardrop camper that will match the Vette. Sounds weird pulling a camper with the Vette but I think if it is done correct it will be cool. Mark