pics of my grille block experiment...

[theholycow]

Good information and ideas, DracoFelis.

I still think the car charger is the easy/cheap/fast way to get a prefab 12v indicator LED. You can often get them at dollar stores, especially if you're not picky about what it's made to charge; or you may be able to get them for free from someone getting rid of a phone.

If you're going to the effort of intstalling LEDs and mounting a switch, why not just skip the brake light LED and mount another switch instead? Then there will be no question and no chance of braking when you don't want to.

[sonyhome]

DracoFelis,

Good idea to monitor brake, ignition-dfco and fan.

If you only monitor 2, I guess you can get a LED with 3 legs. If you monitor 3, then you could get a LED with 4 legs (RGB colors!). However hurry up to Radio Shack. These guys will be going under I bet, they are too expensive, and don't have a decent business model.

Computing LED resistor

BTW, if you want to compute your resistor for your LED, here's how you do it I think:

- Get the reverse voltage of the LED (specifications), usually 1.7V
- Get the reverse current needed to light it, usually 15mA
- Assume the max battery voltage is 14.5V
(Vbat - Vled) = R Iled

=> R= (Vbat - Vled)/Iled

For a small basic LED:
R = (14.5-1.7)/15 * 1000 = 800 ohms

A smaller resistance will make it brighter, till it burns (when it burns, the light will dim irreversibly as it gets destroyed, and then will go black)

Some specs from LED101:

small: 15mA, 1.7V
medium: 25mA, 2V

Specialty. high brightness LEDs will come with their own specs, that may be much higher, like 5V or 1000mA (1amp!).

[theholycow]

Nice info!

I don't think Radio Shack's business model is broken, nor will they go under. They have a great business model: Have no competition for a large portion of your inventory, be positioned as the place to go when you need help with the rest (by being a small store with people that will take a couple minutes to fail to help with your cell phone or R/C car), and charge too much for everything. It's worked for them for decades...the only difference now is that you can buy LEDs and transistors online -- which doesn't help when my project needs it right now.

[sonyhome]

Every time I go there, there's noone, or almost. Their biggest business is cell phones, with mondo competition. They ditched their core business for that. Electronic gear parts is overpriced because not a big sell anymore. It's even hard to find parts at RS now. Their competition is the web and complexity of electronic gears.
RC cars are sold by toy stores.
They don't really sell/make their own electronic gear any more (like stereos).
I bought at Radio Shack a ref book on the intel 80386 way back. not today!

BTW I'm not happy about it, but they're on their way out IMHO.

Note: I live in silicon valley, and there's not a single decent electronic store around. Go figure.
(end of off topic)

[slurp812]

I took the block off today. My fan comes on at least a few times per trip when I drive. Normally its never on, I try not to idle much. It will go back on when the temps drop. I will see how this effects my overall...

[Hasbro]

Rats. I'm blocking vicariously through you and live in Tuscon. What about increasing the opening some more? Are you going to mess with the upper grill?

[GasSavers_Mr_C]

For those of you who want to monitor the fans, Don't forget that if you already have a Scangauge 2 that supports the Xgauge (I think any one purchased in the last year) on many vehicles you can program it to monitor if your fan is on or off... no parts or cost if you already are running a Scangauge.

I left my top grill open and blocked under the bumper on my car. I thought everything was good, but have since realized that the fan was turning on at highway speeds. I couldn't tell by the gauges and listening, but with the Scanguage I could watch the temp and it woudl go up to 215, then the fan would kick in and it woudl drop down to about 200 (thermostat is 195). Digital gauges rock. :-)

In my case, I have black duct tape as my grill block (because I have a Bra, which has screen over the openings). I have just been slowly removing duct tape until it stays cool enough not to turn the fan on at speed on a warm day.

-Mr_C

[slurp812]

Originally Posted by Mr_C

For those of you who want to monitor the fans, Don't forget that if you already have a Scangauge 2 that supports the Xgauge (I think any one purchased in the last year) on many vehicles you can program it to monitor if your fan is on or off... no parts or cost if you already are running a Scangauge.

DOH! Thanks for that info. I could use the LED for other things aw well. I am going to lookinto the upper grille block, and cutting some off of the bottom, so it blocks less. I will post here!

[theholycow]

There's an idea -- add a bra, and now you can do lots of grille blocking underneath it and not have it attract attention...well, any more than you'd get with a bra nowadays.

[GasSavers_Mr_C]

It isn't the prettiest thing in the world... but it doesn't attract much attention either. The nice thing is the bra on my car already has a screen over most of the coverings, so there is a little flow restriction right there. Plus, I pulled off the upper part of the bra that goes over the hood. that wasn't doing me any good anyway. Right now the bottom is just covered with black duct tape, Once I know its how I want it I will sew on some black vinyl to make it match nicer and last longer.




-Mr_C