Digital side car power

[Gdeaver]

I just want to give a heads up on a problem with a digital side car we had today. We have 3 Sharp IR sensors connected to the digital IO's. We were getting unstable readings from them. Before we had monitored them with a separate micro controller board and they worked fine. We found that we had to add a 100 uf cap across ground and 5+ to get a stable voltage to them. If other teams are having stability problems with the DIO and every thing else is right then the problem may be with the power. Try a cap. We had a similar problem with one analog break out last year.

[Al Skierkiewicz]

Gary,
This is highly unusual. The 5 volt supply on the DSC is capable of several amps. It sounds like you might have a loose wire in the 12 volt line feeding the DSC.

[RufflesRidge]

Al, in my experience the Sharp IR sensors (though my experience was with the analog variety) are very sensitive to line noise on the 5V rail. The switching supply used in the DSC probably has enough output ripple to cause headaches for those particular sensors.

[Al Skierkiewicz]

The 5 volt supply has a 330mfd cap across the output.

[wireties]

A filter and a bypass cap VERY close to the sensor will do the most good.