[PD] PD, arduino and sharp range detectors
Hi All, We are having trouble with a PD - Arduino - Sharp IR gp2d12 IR range sensor. everything works for a while, then the arduino just stops and sometimes takes PD down with it. once we had a warning from the OS that there was too much current being sucked on the USB port. we are using three such things, each uses typically 33 and up to 50 mA. This should (according to the Arduino and USB specs) not be too much, but perhaps these are wrong. Any other ideas? I have heard of people using smoothing capacitors on the sharp sensors. Hmm, puzzled in Linz, Tim ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] PD, arduino and sharp range detectors
Tim Boykett wrote: We are having trouble with a PD - Arduino - Sharp IR gp2d12 IR range sensor. everything works for a while, then the arduino just stops and sometimes takes PD down with it. once we had a warning from the OS that there was too much current being sucked on the USB port. we are using three such things, each uses typically 33 and up to 50 mA. This should (according to the Arduino and USB specs) not be too much, but perhaps these are wrong. I have built a circuit with six of those sensors on an Arduino Diecimila, it worked fine with external power, but I didn't even try it with USB power because for me 50mA is too much. (At first it crashed sporadically because I was sending too much data through the serial port.) The actual USB port you are using may not be able to supply that much current even if the USB circuit is able to handle it. If it only happens occasionally it's probably because the sensors sometimes pull more than the average current, so a ~100uF capacitor on the power pins would help, but you should really use a separate power supply for the sensors, or just power the entire Arduino externally. Martin ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] PD, arduino and sharp range detectors
that seems to be the case! thanks tim On 30 Oct 2008, at 17:41, Martin Peach wrote: Tim Boykett wrote: We are having trouble with a PD - Arduino - Sharp IR gp2d12 IR range sensor. everything works for a while, then the arduino just stops and sometimes takes PD down with it. once we had a warning from the OS that there was too much current being sucked on the USB port. we are using three such things, each uses typically 33 and up to 50 mA. This should (according to the Arduino and USB specs) not be too much, but perhaps these are wrong. I have built a circuit with six of those sensors on an Arduino Diecimila, it worked fine with external power, but I didn't even try it with USB power because for me 50mA is too much. (At first it crashed sporadically because I was sending too much data through the serial port.) The actual USB port you are using may not be able to supply that much current even if the USB circuit is able to handle it. If it only happens occasionally it's probably because the sensors sometimes pull more than the average current, so a ~100uF capacitor on the power pins would help, but you should really use a separate power supply for the sensors, or just power the entire Arduino externally. Martin ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
