Control of Decorations (Led displays)

[tagayoff]

How does one go about controlling the on/off function of some LED displays.
<R44> Lets you power them but <R60> says you can only control pneumatic solenoids and now line tracking sensors (Update). So do you build a custom circuit the can take a DI/O output to control them or are they just on all the time? Rookie team member is :confused: .

[foozie]

You can use the DIOs on the Digital Sidecar.

[Alan Anderson]

We'll be using a Spike relay module to power our robot's lights.

[KHall]

May I suggest you look at some of the 'blinky LED' projects listed at this site:

http://www.kpsec.freeuk.com/proj.htm

If you want to learn more about how to create the projects, there is a link at the bottom of that page that says "Study Electronics". Click on that and proceed page by page though the instructions. Should only take a little while. If you come to a page that does not interest you, just skip it for now. You can always go back and review it later. When you're done, you'll fully understand the information listed for each project. With a little work you can modify these projects for your robot.

If you're looking for the parts, let me know. I can recommend a good place to get these things in the USA that won't cost too much.

Regards,
KHall

[tagayoff]

I guess I haven't made myself clear yet. I would like to use some (3) joystick buttons to turn on/off three sets of led displays that use 12volts. I know I could use 3 spike relay modules but that seems overkill. (But it may be the only way it's permitted.) The DIO's only drive miminal current at 5 volts I think. I would have to have a custom driver from that to switch the 12 volts . That would be more reasonable but is it permissible?
:confused:

[WizenedEE]

You can build whatever custom circuit you want to control decorations and non-motors, is what our team decided. Rule <R04> (I think) says you cannot control "output devices" with custom circuits or COTS electronics. We decided that LEDs are not output devices.

If you want to use spikes, you can easily control each of the two leads directly, so that's LEDs per spike. See this thread: http://www.chiefdelphi.com/forums/showthread.php?t=89207

[Al Skierkiewicz]

Adam,
It's R03. The 9403 data I/O module is directly connected to the digital side car I/O and the sum of all outputs cannot exceed 64 ma. Using the digital outputs for LEDs is not a good idea. I believe that a high current LED driver would be legal as a custom circuit provided it does not violate any other rule, specifically electrical rules. Spikes are still the best alternative as far as ease of use, interface and wiring.

[dsmith14469]

Here is a simple circuit using a MOSFET Switch. http://www.newark.com/vishay-semiconductor/vo14642at/ssr-mosfet-60v-2a/dp/66M1368?Ntt=66M1368

This MOSFET is overkill for simple LEDs, 2 Amp rating.:)

Just connect the DIO from the digital side car, add the correct resistors to not fry any parts and you should be good to go.

Hope this help.

[maddoctor90]

<R56> Relay module outputs, speed controller outputs, or PWM outputs must not be connected to the analog/solenoid breakout boards or the Digital Sidecar. 12Vdc power must not be connected to any terminal on the analog/solenoid breakout boards or the Digital Sidecar except the designated 12Vdc input terminals. (Doing so may damage or destroy components of the control system.)

So, you can't use the 12v off of the sidecar. Although, I am not sure if you can use the 5v to switch a 12v source legally. At a quick glance at the rules, I think it would be ok, although I would want to make sure first for yourself. My team will be using three relay modules for about the same thing because it is easy and we know it is legal. I would suggest you do the same, unless you have some reason not to, or have extra time and feel like experimenting around.

[AndrewN]

Each "spike" can switch two circuits: there are two relays inside that can switch between +12V and 0V. The "fwd", "rev" control signals each control one relay. You could control 4 separate light ropes with 2 "spikes". The "ground" from each rope would be connected back to a black terminal on the power board.

[tagayoff]

Now you tell me after I bought 3 spikes. I guess I should ::rtm::

[Al Skierkiewicz]

First Engineering has now made it easy for you. The IFI docs are linked on the KOP page so you can read the install and use docs for robot components all in one place.

[DavidGitz]

Each "spike" can switch two circuits: there are two relays inside that can switch between +12V and 0V. The "fwd", "rev" control signals each control one relay. You could control 4 separate light ropes with 2 "spikes". The "ground" from each rope would be connected back to a black terminal on the power board.

<R42> Each power-regulating device (speed controller or relay module) shall control one and only one electrical load (motor, actuator or compressor).
Exception: Multiple low-load, pneumatic solenoid valves may be connected to a single relay module. This would allow one relay module to drive multiple pneumatic actions. No other electrical load can be connected to a relay module used in this manner.

From my understanding, a spike can control 2 circuits only if they are low-load, pneumatic solenoid valves. So you cannot control 2 different LED's (although I'm sure the current requirement is comparable).

If someone here disagrees, please let me know. Right now we have 3 relays for this purpose and I would not mind going down to 2!

[Alan Anderson]

<R42>...

From my understanding, a spike can control 2 circuits only if they are low-load, pneumatic solenoid valves. So you cannot control 2 different LED's (although I'm sure the current requirement is comparable).

If someone here disagrees, please let me know. Right now we have 3 relays for this purpose and I would not mind going down to 2!

I read <R42> as applying to motors, actuators, and compressors. I do not believe it applies to custom circuits.

(As always, my opinion counts for exactly nothing when your robot is being inspected.)

[DavidGitz]

So they list the exception as a valve could be considered an actuator? That is a good point.

Off to do some GDC Q&A Research.

[Al Skierkiewicz]

<R42> Each power-regulating device (speed controller or relay module) shall control one and only one electrical load (motor, actuator or compressor).
Exception: Multiple low-load, pneumatic solenoid valves may be connected to a single relay module. This would allow one relay module to drive multiple pneumatic actions. No other electrical load can be connected to a relay module used in this manner.

From my understanding, a spike can control 2 circuits only if they are low-load, pneumatic solenoid valves. So you cannot control 2 different LED's (although I'm sure the current requirement is comparable).

If someone here disagrees, please let me know. Right now we have 3 relays for this purpose and I would not mind going down to 2!
David,
The multiple "low load" solenoid valves relate to the Crio solenoid/relay module. The Spike Relay module can control electrical loads up to 20 amps and can control multiple solenoids using the wiring suggested above.
See...http://content.vexrobotics.com/docs/spike-blue-guide-sep05.pdf for a full description.
As long as you keep each LED string below 10 amps each and follow all other robot rules, you should have no problem.
Please be advised, bright LED strings, flashy decorations, or objects that mimic or emit light that can interfere with other robots using optical sensors may be viewed as objectionable under other FRC rules. Inspectors, refs or other officials may require you to disable them.

[DavidGitz]

Al - Thanks for the clarification. I agree the current requirement will not even be close to exceeding the limitations of the spike relay, ours are about 30 mA max.

I may be "lawyering" these rules too much, but I am trying to make sure that I understand them fully. The document you specified was the one I was discussing as well. That document only specifies controlling 2 devices if they are solenoid valves. Obviously that document is not FIRST official but is just a reference.

So you are saying that the "single relay module" from the rules is not referring to the spike relay but is instead referencing the solenoid breakout, as seen here (http://www.andymark.com/ProductDetails.asp?ProductCode=am-0268)? I don't think this is true, and I think that I am misreading your post (although you did say "Crio solenoid/relay module").

So the question remains, are LED's (and their associated circuitry) considered an actuator? If so, then only one module may be controlled through a spike relay. If not, then there are no rule limitations (in this context, obviously practicality,safety and electrical limits apply) to how many be controlled by one relay.

I feel that I am beating this to death, and I will defer to your wisdom as an outstanding Robot Inspector.

[Al Skierkiewicz]

David,
The interface you linked to is simply an add on module to the NI 9472 Crio module that came in your KOP. Each output can be accessed through the linked interface using PWM style connectors. The 9472 module has certain current limitations, 0.75 amps per output or 6 amps total for the module.
The Spike can handle significantly more current. However, I have yet to see a robot design that would require a large number of solenoids firing all at once from the same trigger signal. Since the Spike can handle currents up to 20 amps total (it is fused for 20 amps) it is commonly used for controlling higher current loads. Teams have used them to control decorations in the past. If you are proposing just one 30 ma LED, it is an overkill for the Spike I know. Unfortunately, there is no convenient way to power the LED through current hardware. I would ask the question of the Q&A as I don't remember this particular application has been approached before. Ask if you can use the solenoid module (9472) to drive LED loads and ask if you can use a relay or digital output of the digital sidecar to drive a custom circuit that would power the LED. (A simple transistor would suffice for the later.) I don't remember any rule off the top of my head that would prevent either, but will check later when I have more time.

BTW, the linked module is required to interface to the NI 9472 that came in KOP. There is an interface module included in your KOP.

[Alan Anderson]

...ask if you can use a relay output of the digital sidecar to drive a custom circuit that would power the LED. (A simple transistor would suffice...)

If you're going to do a custom driver circuit anyway, don't bother with abusing the relay outputs. Just use a Digital I/O pin.

[Joe Ross]

So the question remains, are LED's (and their associated circuitry) considered an actuator? If so, then only one module may be controlled through a spike relay. If not, then there are no rule limitations (in this context, obviously practicality,safety and electrical limits apply) to how many be controlled by one relay.

I'm not sure how something that doesn't move or cause motion could be considered an actuator.

[elbuo]

I just wish to clarify something,

If I use 5v lights, can I attach them directly to my DSC in the DIO side? That way I would just open and close to channel to turn on or off a light.

[Alan Anderson]

If I use 5v lights, can I attach them directly to my DSC in the DIO side?

The DIO pins are connected directly to the NI 9403 module, with a 10k pullup resistor to +5 volts. The module is capable of sourcing 2 milliamps per channel.
The Digital Sidecar 5v power supply is rated at 3A total. I don't know how much of that is available for use by external circuitry.

[Al Skierkiewicz]

Alan and elbuo,
The 9403 module is speced at source and/or sink of 2 ma per output. Not enough to drive an LED.