power supply

mmoreland

Is it a mistake to power a BS2p using a 7.5vdc wall adapter that has been modified with a 9v battery snap and attaching it to the 9v battery port on the stamp board? More importantly, was the stamp likely damaged when I attached the power supply with the voltage polarity reversed for a few minutes before realizing my mistake? The stamp accepts the code and runs the program, but the SLEEP function appears to have been disabled. Does that make any sense?

mmoreland

SLEEP and NAP functions are dead. All else works. Too bad. Any help for this?

erco

Those results are interesting. Is this a standard Board of Education? I would have thought that the BoE had reverse polarity protection. I wonder if you may have damaged the BoE regulator instead of the Stamp. If that's the case, you could replace the regulator. Of course Stamps have their own seperate onboard 5V regulator. You could CAREFULLY apply +9V to Vin (disconnecting the +5V pin) and see if your SLEEP/NAP functions return.

As you rather painfully found out, when you wire up a battery eliminator using a 9V snap, the polarity gets reversed. You aren't the first and you won't be the last. The good news: you (probably) won't ever make that mistake again.

20-20 hindsight is all too clear: test continually with your multimeter and work slowly & methodically.

Mike Green

Assuming that you attached the 7.5V to Vin and Vss (ground), the regulator on the Stamp module may have protected you. It doesn't make sense that SLEEP and NAP don't work while everything else does. SLEEP and NAP are not separate portions of the Stamp although they use slightly different clock circuitry when they're actually in low power mode. How can you tell that they don't work?

mmoreland

The stamp would run the code which checked an accelerometer, checked GPS and sent a rotation value to a motor, and it did this until the accelerometer which the motor was tilting, was at the correct angle. Then it was to sleep for a period of time. If I set the SLEEP time to five seconds or the NAP time to 7, the entire operation stopped there. If I substituted PAUSE 5000 for the sleep command, the entire operation continued with checking the accelerometer and GPS every five seconds. I then wrote a small separate piece of code just to check the functionality of SLEEP, NAP AND PAUSE, and it gave an appropriate response to PAUSE, but took no action after the SLEEP or NAP commands even though they were essentially the same interval as the PAUSE. I substituted a BS2pe, changed all the appropriate variables, and SLEEP, NAP and PAUSE all work perfectly. In order to test the new stamp, I tossed the battery clip and wired the adapter directly to the Vin and Vss pins instead of the battery port. In the beginning, to develop the program, I used a board of education, but for the permanent installation, I've switched to a simpler board with only a serial adapter and a battery clip plus two rows of pins.