When I was talking with people about how some badges use two pins of the attiny, I basically explained it to myself while trying to explain to others why it would be louder. Instead of just pushing the speaker from the resting position, you also pull it back, when connecting both the inverted oscillator pins to a speaker. Now at the airport and thanks to seeing Charles Lohr at the supercon, I remembered that he actually did that. I need to further hack that bodged prototype I guess :D
Friday night at supercon I decided to spend some time on the I2C part of the firmware. It's pretty simple, but I'm now able to send data from the #Penghicorn badge to this SAO and it will play a tone. Of course this can be further expanded, but I'm quite happy with the beeps. The speaker is very quite though and I need to take a look at other preferably surface mount speakers. Someone made a beeping R2D2 SAO and that has a nice speaker I want to check out.