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It's been slow going so far. I'm using a pressure sensor from the computer store but its output range is too small for the PIC to sample (about 35 mV total) so I've been working on amplifying it with an op-amp. I think I've finally got it down and if anyone is using a sensor that needs a little boost, I've got some amplifiers to lend. Try using a Wheatstone bridge with that pressure sensor. We've set up a wheatstone bridge, but we're only seeing a value range of 10 from our sensor using the ADC Compare code on the PIC. Is this what we should expect? Pictures of our bridge are at http://itp.nyu.edu/~rcc273/blog/?p=17. Your setup looks good. Try changing the reference voltage on the ADC. To do this, set ADCON1 = %10000001, and put a pot on PORTA.3. This makes that pin a voltage reference, so that the PIC compares the other analog pins' inputs to that voltage, instead of to 5V. Tune the pot until you're getting about 3V on PORTA.3 (measure it with a voltmeter), and then see what kinds of readings you're getting out of the program. I'm assuming you're using a program like this one? Question regarding step 3 of the Serial Output lab: When an LED is plugged into the serial output pin of the PIC, the LED appears to just stay on, not blink, when the PIC is sending serial messages. Is it actually blinking, just too fast for our perception? yes. Here is the code I was talking about in class today that made the PIC reset twice and stop. Any thoughts? Summer and I did this lab together. We used it as an opportunity to workshop some device project code. Note -- there is an image of our patch in the documentation that may be helpful to anyone wanting to communicate serially to Jitter. Jet and Summer Lab #5 |