Wiring a Flashlight, 2013 version

Technical Electrical
#1

Copying this question from the photon cannon thread to a forum where the electrical guys can weigh in, and I didn’t see anything in Q&A addressing this. 2 Questions:

  1. It appears that this year because of R52 and Table 4-4 that you can’t run a flashlight through a Spike relay - A flashlight doesn’t appear to be a “Legal Power Regulating Device Use” since it isn’t listed as an allowable load anywhere for the Spike. Agree?

  2. It looks like wiring to a flashlight could be run directly from the 5V connector on the PD board per R39. Is this true?

#2

Pointed out to me by someone else that the * under pneumatic solenoids in Table 4-4 discusses controlling multiple lights with a relay - is it covered by that?

#3

Emphasis mine.

To me, this seems to mean that if an electrical load is not enumerated in table 4-4, then it can be controlled using a power-regulating device, but only one of them per power regulating device (so multiple low-current lights could be powered by a single spike; only one high-current light could be controlled per spike. not sure what determines low-current vs high-current - probably whether the total current draw is under the max current rating of the spike).

[strike]R53[/strike] R54 says that custom circuits can’t affect the power pathway of other custom circuits, but if you were to make a custom flashlight-like device that included a relay to switch it on and off, that seems like it would be legal to me.

Overall, seems like a question for the Q&A.

#4

R53 is about solenoids. I think you meant R54, which says:

Custom circuits shall not directly alter the power pathways between the ROBOT battery, PD Board, motor controllers, relays, motors, or other elements of the ROBOT control system (including the power pathways to other sensors or circuits). …

The “Custom circuit” in this case is just the flashlight (and the wire that goes between the relay and the flashlight). So, the custom circuit is not altering the power pathway to anything else, so it doesn’t violate R54.

The text at the bottom of Table 4-4 says:

Multiple low-load, pneumatic solenoid valves or lights may be connected to a single relay module. This would allow one (1) relay module to drive multiple pneumatic actions or multiple lights. No other electrical load can be connected to a relay module used in this manner.

(emphasis mine)

So, it seems pretty clear that a relay to turn the flashlight on and off isn’t violating R52 (Table 4-4) either.

#5

Correct; thank you for the correction

#6

It seems wiring a flashlight is very tough job. Do you have any circuit diagram which could simplify bit more? Thanks in advance:)

#7

Do you have a particular flashlight in mind? I know what we did was use a spike relay to handle the on/off control and then connected that you a (fuse protected) DC-DC voltage regulator (product number BOB-09370 from sparkfun for the exact one). The voltage regulator was tuned to around 4.5 volts (Or something close to that) which matched what the LED required.