Garfieldboy

Member Since: December 11, 2008

Country: United States

  • I agree with stcarlso, you have a signal path from V1 to V2 through R3-R13-R30-R28 in your PRETESTS circuits (and also to the processor GPIO). Both PRETEST circuits use the same GPIO to control them so even though they are really driven from the micro there will still potentially be some leakage that affects/biases the GPIO a little. Alternatively the voltage you are seeing may actually be just from the GPIO back feeding into the supply through the PRETEST resistors ?

  • I often (well, not TOO often) use a somewhat similar method, but rather than trying to blow the ‘fuse’ I search for the hot spot. I use a current limited power supply and slowly ramp up the current. Occasionally this is enough to blow the unwanted ‘fuse’, but for harder shorts I go looking for heat. If I am feeling brave this is done using a uni-pixel thermal scanning sensor (my finger). For more complex boards, or boards with components on both side where the mono-scanner can’t pass smoothly I use a thermal camera. This also works for circuits with faulty components and/or incorrectly connected components. Proved very useful on one particular design when I updated an ADC to a higher performance ADC in the same family/package only to discover one of the ground connections had been re-tasked as a power supply. The updated ADC shorted the power internally. Once discovered simply lifting the rogue leg fixed the issue.

  • Whilst the original Pixy was great at object detection, getting the coordinates out was a nightmare though!!! We tried using it to detect 2 retro-flective markers, and whilst the detection of the markers worked fantastically, the I2C interface protocol to retrieve the data was so convoluted we eventually gave up since we couldn’t do it reliably.

    The biggest issue seemed to be that the data retrieved from I2C was basically a stream with supposed synchronization markers. You would expect this to be a great system, but the implementation simply didn’t work reliably when trying to handle more than one object in a single video frame. It was also almost as though the coordinates were cleared out at the start of each video frame, so often you would read block data and it would return a zero coordinates and/or just flat out get out of sync.

    I would really have liked a “capture” command, “status” command and a “retrieve coordinates” command.

    I will look through the interface documentation. Hopefully they have moved away from the stream format and/or made sure that once you start to retrieve a frame set nothing else is updated until you finished.

  • Came across a GREAT tip a while back to measure the center to center spacing for 2 (same sized) holes.

    Use the calipers to measure the inside opening of one hole, then zero the calipers whilst making this measurement. Effectively now all measurements will have this distance subtracted.

    Now measure the outside to outside distance of the 2 holes and the reading will now represent the center to center spacing.

    This only works of the holes are the same size though, but still extremely useful tip.

  • After getting in with the wrong crowd in his teens Luxo Jr. lost all his cuteness and turned into a ruthless killing machine.

  • Arghhh. I keep sending my comments to the “What’s on your mind” !!! I always scroll down too far before commenting.

    Aaaaaanywhooo.

    “Everyone with a backorder will get their stuff, it’s just going to take us a bit of time”

    WOW, what can I say ?? Fantastic.

    I don’t think I have ever come across a company that would honor the orders in this situation. In the past I have had orders cancelled and money refunded days after placing an order and getting confirmation, but not here at SF.

    SF, you ROCK!!!

  • OK, a little confused. Got SF e-mail saying the order is back ordered and I won’t be charged until available but also a message from PayPal confirming the payment !!??

  • YAYYYYY!!! “Thank you for your order! ” WOW, this brought SF to a crawl through !!!

    Very amusing

  • Tired of wasting time strolling around WalMart Casey decides to speed up his cart a little…

  • SIM cards from here might be worth trying. Seem pretty low cost for low data usage. http://www.onesimcard.com/m2m-data-rates/?dcountry=US

No public wish lists :(