LEDs connected to Solenoid Breakout. It's illegal, but why?
 

From the rules, it is illegal to connect anything but solenoids and the line sensors to the solenoid breakout. We have 3 LED strings, pulling about 300mA a piece. We would love to save some space and connect them to the solenoid breakout board, but guess what...

Any reason why custom circuits are not allowed? It's adding unnecessary complication to our already over complicated robot.

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

The only reason that matters is because it is in the rules. Same reason we're not allowed to use Duct Tape on the minibot.

I can speculate that they are concerned that teams will draw too much current from the breakout and make their pneumatics uncontrollable or erratic.

Side note: a 300 mA LED is about 1 watt. This will be BLINDINGLY bright.

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

Yep, they're pretty bright all put together. I think there are about 30 LEDs in the string.

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

The NI 9472 Digital Sourcing Module has protection against extreme overcurrent, so you probably wouln't be able to cause any fires, but the documentation warns that at currents between 1 and 13 amps the module "may be damaged".

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

Believe me, my students were a bit ticked at this as well.

The solenoid breakout is simply the BEST way to power your LED light indicators.

Unfortunately, from my reading of the rules, that would be illegal.

I agree that we would all benefit from a loosening of the rules of what can be hooked up to the solenoid breakout to include custom circuits < 500mA.

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

I believe the best way to handle this is to make the request in the Q&A.

The wording for the rule change that would allow this would be awkward, as the solenoid breakout can sometimes be used with the 24V rail. I would hope that the rule change would not allow using that rail for LEDs.

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

Does this rule apply to the 2012 season, as I can't find anything that specifically prohibits the LEDs in this year's manual?

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

I think the applicable rule this year is:

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

There are other ways to control LEDs that do not include the solenoid breakout. 300 ma is (As Alan has pointed out) excessive for the solenoid module. The manufacturer recommends 75 ma per output as a safe use of this module. It is for this reason that electric solenoid actuators or 10 watts or less can be driven from this module as well.

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

How about something like this...

<R60> Solenoid Breakout outputs shall be connected to pneumatic valve solenoids, photoelectric sensors, PN 42EF-D1MNAK-A2, or current limited, non-game related circuits only. For non-game related circuits, a total of 3 outputs may be used only for powering decorative lighting or sound circuits that do not contribute to the robots game playing capability. These optional circuits may only be connected to a 12 volt breakout board, (24 volt operation prohibited) and must include a fast acting current limiting fuse not to exceed 500ma. For ease of inspection, the fuse should be an inline fuse connected within 8 inches of the breakout board. No other devices shall be connected to these outputs.

Note: Because optional lighting devices are not game related, and are often custom, judges are provided wide leeway to disallow such circuits. Remember to keep these circuits simple, neat, and be prepared to provide additional documentation if requested.

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

tsaska, that particular post was made for the 2011 season. See squirrel's post for the current rule.

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

I'm curious why you think a 300 ma led is excessive but an 800 ma solenoid is ok.

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

The datasheet for the Solenoid Breakout board specifies 750mA per output channel.

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

Sorry,
Left off the last zero. 750 ma at 12 volts is 9 watts.
Joe, I was considering the total for LEDs for three strings plus the loads likely for other devices as totaling more than one amp. As Alan reminded me last year the manufacturer has this rather odd table listing for trip modes. One of those lines for total current is this...
"1 to 6 A, Channel does not trip, Module may be damaged."

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

A Spike may be bulkier, but you could use one spike to switch two banks of LEDs by wiring each motor output to the positive side of the LED and running the common directly back to the PDB.

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

Alternatively, a simple transistor LED driver can be made. Use one digital out pin per LED string.
The driver only needs one CORRECTLY SIZED resistor and transistor per string to work. Just use +12vdc to power it, and control it via the DSC.

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

So if i had an LED strip rated at 200ma (12v) It'd be alright to run off the solenoid breakout?

If its only one strip and minimal other things using the breakout

Re: LEDs connected to Solenoid Breakout. It's illegal, but why?
 

Aren,
Again subject to GDC desicision, but

[R63]
Outputs from each Solenoid Breakout shall not cumulatively exceed 16W for the cRIO-FRC (8-slot) and 21W for
the cRIO-FRC II (4-slot).

[R50]
e. Electric solenoids may alternatively be supplied by a Solenoid Breakout Board connected to the NI 9472
cRIO module, which is powered by 12V.

I find no other restrictions on the solenoid module for 2012.