View Full Version : Lap counter, What port? Mounting Rule 18
ericsundbergva
18-02-2008, 05:09
The rules say to wire a male PWM plus within 4 inches of the flag pole mount and wire to an analog or digital controller port.
1. Which port works with the default software
2. The rule R18 diagram is unclear. It appears to be a view looking down on the bot with the clear area to the rear, but the lap indiactor needs an upward view. Perhaps that radius area needs to be 360 and provides a cone of vision of 45 degrees up?
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COMMENT a male plug hanging lose risks being shorted. They should have made it female!
Any port will do. The point of this wire is simply to provide power to the lap indicator.
Yes, the male end does risk shorting, and a female end would not. However, since the RC has male outputs, this enables teams to just run a pwm cable up to the flag holder, rather than forcing them to make a female-female cable.
I am not sure where the electrical team came up with it, but we have a PWM with a shielded male end that sort of looks like a female end. The shield provides protection for both shorting and damagining the pins.
MrForbes
18-02-2008, 08:47
Those hooded connectors are used in R/C stuff like airplanes and cars.
Phil Ross
18-02-2008, 08:52
the open radius needs to be 180 degrees i believe and you need a male PWM connector within 4 inches of the flag mount.
so it doesnt matter if connect the pwm to a digital in/out that we have set to "off"
(ie. rcdig_in_01 = 0; could we use digital input 01 as a pwm port to power the lap counter)
:cool: :p ;)
danshaffer
18-02-2008, 11:34
so it doesnt matter if connect the pwm to a digital in/out that we have set to "off"
(ie. rcdig_in_01 = 0; could we use digital input 01 as a pwm port to power the lap counter)
:cool: :p ;)
yup...
digital pins should have a +5, GND and logic line. All of the +5s are connected, all of the GNDs are connected. You have software control over the signal port only.
Greg Needel
18-02-2008, 11:34
so it doesnt matter if connect the pwm to a digital in/out that we have set to "off"
(ie. rcdig_in_01 = 0; could we use digital input 01 as a pwm port to power the lap counter)
:cool: :p ;)
sure you could set it to a Digital in/out that is off (although the pins are always powered) but I guess you won't want your points for lapping. I am sure the other alliance would have no problems with you doing this.:yikes:
Kingofl337
18-02-2008, 16:49
Team 40 went to Suffield to test our 08 robot this weekend and the Signal wire is not even connected. The Flag basically has a little clear plastic box with a circuit inside connected to the flag pole. The circuit gives the robot zero feedback, it just leaches 5v power from the RC. I hope FIRST has implemented protection for teams that accidentally hook up the flag power to the 7.2v PWM lines.
sure you could set it to a Digital in/out that is off (although the pins are always powered) but I guess you won't want your points for lapping. I am sure the other alliance would have no problems with you doing this.:yikes:
What are you talking about? As you note, the I/O pins are always powered, so it doesn't matter what's going on in software.
ericsundbergva
19-02-2008, 05:44
To clarify, I presume the lap indicator has some way to identify the robot and is not just a LED.
So does it have an integral data signature being sent out, (The Judges provide so this may be it) or is it in the bot software????
Eric
JBotAlan
19-02-2008, 08:22
To clarify, I presume the lap indicator has some way to identify the robot and is not just a LED.
So does it have an integral data signature being sent out, (The Judges provide so this may be it) or is it in the bot software????
Eric
I don't think this is a matter to be concerned about. They told us its operation would be verified before the start of the match, so we're fine.
Nothing is in the bot software. This lap counter pulls 5v from the RC, nothing more. Your code has absolutely no influence over what the lap counter does, unless you mis-wire it--it connects to the red wire (5v) and the black wire (GND), neither of which your code has control over.
JBot
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