Does the PD board Output 12v Stable?

[Racer26]

Also, I'm having a hard time imagining what you could possibly want from a secondary computer on board. The PowerPC processor in the cRIO is the most powerful CPU we've ever had at our disposal, by a factor of like 100. If it can't do what you're trying to do with an off-cRIO processor, I'd be surprised.

[EricVanWyk]

Originally Posted by s0crates

Its a picoPSU-90, outputting 90 watts, for providing power to a motherboard we'll be using to supplement processing power.

-jonathan

The 12V supply is only capable of 20 watts. Therefore, you can't do this, regardless of the rules.

I am interested in what you are trying to accomplish. We might be able to help you find a better way.

[lukevanoort]

Originally Posted by 1075guy

Also, I'm having a hard time imagining what you could possibly want from a secondary computer on board. The PowerPC processor in the cRIO is the most powerful CPU we've ever had at our disposal, by a factor of like 100. If it can't do what you're trying to do with an off-cRIO processor, I'd be surprised.

In theory, one could connect a coprocessor to the control system via I2C and use the coprocessor to provide serial communication with some sensor. It would be a rather sneaky way to get around FIRST banning use of the serial port on the cRIO, but would be technically legal.

[Racer26]

I suppose, though IMO, its alot of added electronics and stuff to talk to some sensor, and if it requires that kind of nonsense to talk to it, its probably more complicated of a sensor than you really require.

[s0crates]

Originally Posted by writchie

The serial port is not available for use during the competition this year.

We are aware of this; we will wire the serial port to the gpio of a digital sidecar.

Originally Posted by 1075guy

Also, I'm having a hard time imagining what you could possibly want from a secondary computer on board. The PowerPC processor in the cRIO is the most powerful CPU we've ever had at our disposal, by a factor of like 100. If it can't do what you're trying to do with an off-cRIO processor, I'd be surprised.

Our robot design has forced us to become something of a sniper - we should have the accuracy, and want additional speed in processing images. We may use a second camera to help with targeting.
The fact tha the old processor was 1/100th of the current one doesn't mean the new one is blazing fast, it means the old one was very slow.
I don't view ~450 mhz as very fast, particularly when we can only get image processing (at the lowest possible resolution) to run at about 20 fps, with nearly no other operations running simultaneously.

Originally Posted by EricVanWyk

The 12V supply is only capable of 20 watts. Therefore, you can't do this, regardless of the rules.

Do you mean 20 amps?
Watts = Amps x Voltage
20 = Amps x 12
Amps = 20/12 = 1.67

I'm pretty certain that the motors draw more than that.



-jonathan

[MikeDubreuil]

Originally Posted by s0crates

Do you mean 20 amps?

No, he means the regulated 12V output can only support up to 20 watts; which is enough for the wireless bridge. The other power distribution outputs are limited by the circuit breakers (20, 30, 40 Amps.)

[s0crates]

Errr... How is the regulated power supply relevant?


-jonathan

[MikeDubreuil]

Originally Posted by s0crates

Errr... How is the regulated power supply relevant?

Originally Posted by s0crates

My team is using a custom circuit that doesn't have very much tolerance for voltages that aren't exactly 12v. I know the battery jumps around a lot, but once it goes through the power distribution board, is the voltage exactly 12v, or should i look into other circuits that regulate voltage to 12v. Thanks.

You wanted a clean 12V supply for your custom electrics. The only clean 12V supply is provided by the regulated 12V output for the wireless bridge. Eric mentioned that for your application the regulated 12V supply does not offer the 90 Watts you need; only 20 Watts, and it's also by rule exclusively for the wireless bridge.

In the end, if you want a regulated (clean) 12V supply you will have to provide it yourself by attaching to the unregulated outputs (the ones with circuit breakers you add in yourself.)

[s0crates]

The question was meant to address how regular the power was when taken from the unregulated outputs - I'm not planning to plug the wireless bridge into the unregulated power supply, even if it's regulated power would have supplied a high enough wattage to power the motherboard. The main point of the question was to determine how variable the current/voltage was when taken directly from the unregulated supply. Thx everyone for fully answering the question

-jonathan

[EricVanWyk]

Originally Posted by s0crates

The main point of the question was to determine how variable the current/voltage was when taken directly from the unregulated supply.

If the voltage vs time graph were a road, and you were to drive on it, you would lose your lunch. It is a very dirty, very bouncy thing.

[Russ Beavis]

Your Rover Wheels would be completely shredded

Russ