Hi,
Today I've been trying to control these cheap servos I just received :
http://www.ee.ic.ac.uk/pcheung/teaching/DE1_EE/stores/sg90_datasheet.pdf
I tried with these pd patches, without success :
[adc 3] is a potentiometer. I know from the scope my duty cycle is between 1 and 2 ms. I tried with different outputs, including digital at message rate, and analog. Any idea about what i'm doing wrong? I've never used servos, so maybe i'm missing something obvious.
I think you need a space between 11 and ~ when sending to bela_setDigital: double check against the example. To make sure you are generating the expected signal, you could connect the digital output back to an analog input with a wire and send the new analog input to the scope ([dac~ 27 28 29 30]).
However, the digital outputs are 3.3V. The (minimal) datasheet indicates "Voltage: 4.8V - 6V", so I would try to send a 5V signal, instead of 3.3V. You could either use a transistor to do level shifting on the digital outputs or use the analog outputs, which are 5V. These can be addressed with [dac~ 3] to [dac~ 10] from PureData.
Hi Vince, i've been working on something else lately, i'll give it another try this week end and get back to you. Still, i don't know what could be wrong from my first try, as I know as a fact I was sending the servos 1 - 2 ms pulses at 50 hz. Did you try my pd patch? Do you have the same servos (sg90) ?
Lucien
