Race Technology

Okay, I did a search and checked the Knowledge Base.

The current Knowledge Base does not contain a true schematic, instead describing what goes where. For those of us who use our own switch, it's not real helpful. Based on the DL-1 connection document, the bottom of the switch goes to ground, that's clear. The top of the switch goes to "Trig". What's not clear is if a pull-up resistor is needed... this is not stated anywhere, only vaguely referred to in various forum posts. It seems that a 1K resistor is needed, pulled up to +5V. Is it? Who designs circuits with no internal pull-up resistors? If there aren't any, it's an antenna for EMI and a very bad idea...

The LED connections: One end goes to "Stat", but where does the other end go? Normally, LED drivers use pull-down switches, which means the other end would be expected to go to +12V, yet the Knowledge base says that "Stat" is active high... Okay, so the other end of the LED goes to ground? Does the LED require an in-line current limit resistor?

And finally, the present Knowledge Base drawing appears to (still) be wrong. That is, it says to run signals to, among other places, +12V, yet says nothing about the +5V connection above, and doesn't say where to connect +12V to.

Can someone who's been through this please post how to connect it. It's not an impossible situation to solve, but irritating that it could have been so much better described in the Knowledge Base to start.

Just a switch for the trigger. "Pull" it to ground is what a EE would tell you. You don't need a resistor or a pull up/down circuit.

Stat > LED > 12
Just connect the anode (positive) of the LED to a car voltage supply and the cathode to Stat.

5VDC is to power external sensors.

Actually... I am an EE...

Okay on the switch, but the LED still isn't clear. As you describe it, it's wired such that the LED output is active-low. However, the specs list it as "Stat", not "/Stat" which is active low. It also doesn't state whether a series resistor is inside - I'm guessing not since they say it'll drive a lamp.

I'm just bugged RT didn't include a true schematic --- they drew part of it, how hard would it be to include a couple more lines? As Dr. Horrible said, "... so close."

I can figure it out, it just shouldn't require randomly connecting things until they work - that's how stuff gets blow'd up...

There is a transistor (probably) inside the DL1 that closes the circuit on the LED ground.

Car's 12VDC > Anode > Cathode > Stat connection on DL1

It's really that simple.

I put a ~1,000 (IIRC) Ohm resistor in line to cut down the amperage a bit to an LED illuminated switch. Depends on the rating of the lamp you are going to use though.

http://www.race-technology.com/wiki/ind ... gIndicator

The switch connects to ground for the start stop.

Stat output is pulled to gnd when the unit is logging, so you need a resistor and led with the anode of the LED connected to either +5V or +12V.

It sounds like there is an error in the knowledge base, I’ll see about having it changed.

Thanks for the input guys.