5V pin has low power

[willscott]

When I plug a spark into my laptop, I'm measuring a 2.3V drop from the 5v pin to ground (though there is a 5v drop across the USB pins.)

Is this expected?  The sensor I'm trying to power specifies a working range of 3.3-5v, and doesn't seem to be activating with the 2.3v drop from the spark.

Specifically, I'm trying to set up a PIR motion sensor using the guide here:
http://itp.nyu.edu/physcomp/sensors/Reports/PIRMotionSensor

Following those directions, the spark reports a constant analog read of ~350.  This is the open value, essentially the value of the 5volt pin, and the sensor isn't getting sufficient power to ever activate and close the circuit to ground.

[Bluebie]

If the spark is running at all over USB then it definitely has more than 2.3v power supplied to the attiny. Maybe something isn\'t soldered right on your spark?

[digistump]

wilscott -

Do you have multiple Digisparks? If so can you try another?

Can you also try on a second machine if possible?

And, if you have a power supply over 7v can you try powering it by the VIN pin and then check if you get 5v between 5v and ground.

Voltage drop should only be about 0.3v - so let me know if you can try any of those things, especially testing with another Digispark if you have another, and we\'ll get it solved.

[willscott]

Tried with another spark and it shows expected voltage.  The odd thing is that the one with a 2.3v drop interacts with the computer just fine - I can program it and got digiusb to report values back to my machine.

Same behavior on both a linux and mac - the voltage drop across the USB +5v and ground measures at 5v in both cases.

[digistump]

@wilscott - send me an email support at digistump dot com and we\'ll get a replacement your way