Flying Saucer: I've got a servo running on an ATtiny85, thanks to Jeannine Huffman!

I have been following Jeannine Huffman's (and Jim Bock's) work of getting a servo to run on an ATtiny85. When she shared her process, I ordered the parts and got right to work!  I used a TowerPro SG90 hobby motor that I ordered off of Amazon.

My servo moves smoothly for about 30 seconds, but then it sort of stalls out.  It will start again if I turn it off and on again.  I may have issue with my power supply.  I am using 2 coin cell batteries.

This pop-up was a rapid prototype.