Re: Relay to control 2 outputs
 

http://content.vexrobotics.com/docs/...uide-sep05.pdf

The White input (0/1) controls the M+ output (GND/+12v).

The Red input (0/1) controls the M- output (GND/+12v).

Thus, the Spike can drive a motor forward, reverse, or brake (no coast).

or

Drive two solenoids (or LEDs, etc) independently.

Re: Relay to control 2 outputs
 

Thanks for the Jag Idea, it sounds like a great idea. I was going to use team color LEDs though, so I am not going to lay too much with colors.

I was planning to put them in parallel however and use a Zenner Diode to regulate the voltage, simply because a 6 led chain isn't very long. I Have not tested the idea yet. I have never used Zenner Diodes before, Any opinion/experience with it? Other ideas?

Re: Relay to control 2 outputs
 

You can make the chain as long as you like.

You didn't mention a resistor. Could you post a sketch showing how you plan to use the Zener to regulate the voltage to the LEDs?

Re: Relay to control 2 outputs
 

I didn't think about it that way before.

I believe I attached a basic drawing of my idea. I might have the directions of the diodes backwards, I don't really do any work in schematics.

Please bear with me, I am still not very experienced.

Re: Relay to control 2 outputs
 

You've got the Zener shorted across the battery.

Re: Relay to control 2 outputs
 

forget that, he has a conductive loop shorted across the battery (at the far right)!

Wait, I don't see a huge issue with the zener, It is in anti-parallel. X volts go around it and the rest go through it (in a simplified model) . All that is missing is a resistor between everything and the battery to limit current (the wire at the right still needs to go).

Re: Relay to control 2 outputs
 

Yikes! You're right. I stopped looking when I saw the shorted Zener.

That's a pretty big "all". I mentioned the resistor in my earlier post... but whether or not a resistor/Zener circuit even makes sense for this application depends on the current draw for that long chain of LEDs.


Micah, do you understand what we're saying ?

Re: Relay to control 2 outputs
 

Yes I do. I am sorry about the mistakes. I really appreciate the input.

Re: Relay to control 2 outputs
 

Micah,
The zener is not really needed unless you are determined to keep the LEDs at a fixed brilliance. Please remember that the battery voltage on the robot easily gets down into the 6-8 volt range during a match. What Ether showed is four LEDS in a string and several string in parallel with a series resistor to limit the current through the diodes. You could choose a three diode string and recalculate the series resistor. The string would stay on if the voltage falls to the 6 volt range. If you think you are up to it, a current source using a FET or transistor might be a better choice in this application.

Re: Relay to control 2 outputs
 

Excuse my ignorance, but why is a transistor good for this? from my knowledge a transistor is used for controlling outputs based on signals.

Re: Relay to control 2 outputs
 

There's a lot to learn, but if you're interested in this stuff you are fortunate that you live in a time when so much information is right at your fingertips, literally.

Just Google the phrase "voltage regulator" and start reading. You will be amazed at what you find.

Re: Relay to control 2 outputs
 

Micah,
The luminous intensity of an LED is a function of the current flowing through it. With a simple current limiting resistor, the intensity will vary with voltage supplied. In a constant current source, the current will remain the same with a varying supply voltage. Don't know if this is important for your application but I thought I would throw it in anyway. One place this was used in equipment I worked on is an audio console. This particular design used several LEDs for signalling which options had been selected. By wiring several LEDs in series and using a current source, the switches merely shorted across the LEDs that were not needed. The current source then kept the current constant and the LEDs were the same intensity whether one, two or all seven were on.

Re: Relay to control 2 outputs
 

78xx series regulators are almost as simple as using zener diodes. They come in handy when you need a 5 volt signal voltage, but your controller can only operate at 6-24 volts, not that this is really an issue that we face often, since the digital sidecar does all the voltage regulation itself.