digispark no longer available via usb

[teanau]

background:
im doing a basic little lighting setup for an art installation.
a pulsing battery powered led rotating on an old turntable platter.
here are shots of my current progress.

http://www.flickr.com/photos/teanau/11841169486/in/photostream/
http://www.flickr.com/photos/teanau/11840668083/in/photostream/
http://www.flickr.com/photos/teanau/11840668273/in/photostream/

initial testing was going fine,
breadboard leonardo worked fine,
basic digispark test worked fine.
but at some point once i had soldered the digispark into place it stopped making itself available to usb.
it receives power via usb and runs the last program i uploaded to it, but i can't access it to upload a new program.
other digisparks are reporting fine, the arduino ide is obviously working fine, leaving a hardware problem? or something ive done to the digispark bootloader ( i have not intentionally changed the bootloader, it should all be stock )

P0 and P1 are running transistors for the motor and light dimming
P2 is soldered to the signal from the potentiometer
P5 is monitoring a switch ( default open )


system:
win 7 x64

hopefully its obvious.
any pointers appreciated.
thanks in advance for taking a look.

_sam

[dougal]

I'm wondering if you've got too much current draw coming off the DigiSpark... Is all power to other components going through it? If so, try re-wiring so that some of it gets power more directly, especially anything with a high current draw.

Why solder directly to the DigiSpark's USB connector? You could just use pins 3 & 4 on the data header.

I assume you've already inspected closely for a solder-bridge short. It might be possible that you could have overheated something (maybe the USB diode?). Can you post some really close-up shots of the solder connections?

[teanau]

thanks so much for taking the time to have a look.

The led and motor draw their power via the big dc regulator only when the power switch is on.
the same dc regulator powers the digispark via vin when the power switch is on, would i need a diode to prevent the power exiting via vin when the power is off ( no power going to the dc regulator, just power in via usb )?

good to know i can hook usb directly to 3 and 4.

yes ive gone around and continuity tested everything i can think of, nothing seems out of the ordinary?
http://www.flickr.com/photos/teanau/11841810023/

oh dear, i was assuming the 5v pin was 5 volts out, it seems to have just under 5v reporting on the volt meter?
is it intended to be 5 volts in?
_sam

[digistump]

5v pin is 5v out if you are powering via USB or VIN - it is 5v in if you are powering the digi via external 5v. If powered by USB it is normal for it to be 4.5-4.8

what voltage do you get at the 5v pin - when power is only applied via USB? (make sure to disconnect any big loads before trying that)

I'm confused by your wiring - it looks like you have a wire connected to 5v, vin, and of course gnd - what is connected to vin?

[teanau]

thanks for the assistance
im trying to set up two modes to avoid exposing my computer usb to the higher voltages needed for motors and lights.

power switch is off:
   programming mode:
   - usb powered no power going to any of the other components.

power switch is on:
   operating mode:
   - battery power entering digispark VIN  via  dc regulator at 10 volts

the 5v pin is just feeding a switch back to P2

voltage reading at 5v pin = 4.6v when powered by usb

[teanau]

sorry for wasting everyones time.
turns out some usb cables only carry power!!!
they have the contact pads for data, but they are not connected.

that cost me far too much time.
sorry once again and thank you for the support trying to solve this.

im up and running again!

_sam

[digistump]

no problem - that one has got many of us!

looks like a very cool project btw!

[teanau]

ouch, seems like the kind of thing you get caught out by ONCE!
uugh.

yeah will be fun once up an running.
if anyone is around san francisco drop by and see it:

http://www.recologysf.com/index.php/next-art-exhibition

should be fun

_sam