I found headstock tuners to be very unreliable on my Bass. I have used them extensively on my electric guitars and acoustics with no issues, however.
This topic was been covered extensively on the forum not so long ago. Here is a link
And an excerpt from that link that I posted regarding my connection to an Androoid phone.
I highly recommend the istrobosoft phone app, from Peterson, for iphone or Android, but would caution that although it works without the direct connection to the phone it works best with the interface cable and for $7 for the app + $40 for an irig2 interface I ended up with a great strobe tuner for a fraction of the cost of a standalone strobe tuner for hundreds of dollars.