18 servos erco. the pca9685 board don't like not enough power for servos although it has own 5V supply and the servo supply is totally independent.
There's a set all channel command and I use scale..arduino map function but in basic to convert degrees to pulse width. This sets all 18 servos to 90 degrees.....
but with not enough power all servos go to 0 degrees.
My thought is a 8 A bridge rectifier and 7.2V li-ion,4 batterys. The bridge is 2 diodes in series twice so should drop 7.2V to 5V. I've ordered a dc-dc 8A buck converter anyway.
If you nick the init code for these boards they'd work with picaxe.
Also , you can take a wire off the pot in the servo,connect to a-d and get servo position. There's probably a 16 channel a-d i2c chip some where..it seems familiar..I might have some.
I could then teach it to walk. otherwise it's trig or tables.
It needs longer legs so less strain on servos...from first thoughts an tests.