having a little bit of arm surgery. Basil has a total of 33 20kg jx pdi servos
which i buy from banggood at about £8 a servo and at that price you'd expect
to be getting one of the poor quality knock offs but these servos are brilliant
well constructed with metal main body , quiet relitively fast personally i don't
think you'll get much better at lot more money also if your worried about buying
from china these are often available in there uk warehouse at £1 more.
Obviously i could use two or 3 of the breakout boards but decided to make.
a board that would handle most if not all of his functions including speech,
camera in his eyes pir sensor , neopixel ring in his chest , said most of his functions.
Basil has an 8 inch windows Tablet in his back which does the face and object
recognition as well as speech commands via c# program so its really just servos.
but while i was doing a board i'd make it reusable for other projects.Although the ESP32Wroom has a few io pins it doesn't have enough for all the Servos so i was going to need a few more pins. One option was to stick Arm micro
on the board but the micro would cost me a couple of quid plus crystal , regulator
and other parts your looking at spending close £10 as the ESP32Wroom modules can
brought for half the price with plus the bonus of more processing power so i decided to use two of them. one of them has all its pwm pins connected with a row of 0v and V servo the has half its Io in the same configuration the other has a jumper which allows half the pins to have its V servo volts set to 3v3 i also added an audio amp to one of the dac pins and a
1amp dual dc motor driver.
The Board shown here is the rev 1 which had a minor mod due to me connecting two
resistors together in the schematic rev 2 board is being made by Elecrow at time of
writing and gerbers on the dowload page are the rev 2 i'm toying with doing a 3rd rev
as although it works i'm not overly keen on moving the 4 jumpers over to program each
ESP32 module in theory if you add OTA to you project you don't need to change them.
One thing that was not put on this board was the clamping diodes just not enough room
as i wanted to keep the size below the 100x100 and two layer. The board works well in
fact better than expected , having a few problems with atod noise but with the addtion
of a software rc filter the noise level is exceptable the 1117 3v3 regulator copes ok with
the two modules but you don't want to connect much more to i've had a 12 pixel led
ring running off it with both wifi running and one bluetooth and was getting a little
warm but still running and not going into thermal shutdown but if i do a rev 3 i would
be tempted to stick a bigger regulator. I'll be doing further tests as soon as the rev 2
arrives and i have also started a shield type board that plugs into the sockets to operate
my 3D printer currently uses a Rumba arduino type board to run and i have a laptop permantly connected so i can upload files to and it would be great to have it running WiFi.
If you want to build a rev 2 board the gerbers and shematic are on the download page and i recomend elecrow as they
haven't let me down yet, unlike seeed. For those interested i have a home brew D-Bot