Monthly Archives: October 2014

DARwIn-OP body

My DARwIn-OP clone is taking shape. I mounted the chest section.

DARwIn-OP de los pies a los hombros.
DARwIn-OP up to the shoulders.

The chest parts (where the computer is mounted) are pretty big and my mill doesn’t have enough range in the Y axis to mill it in one cut. Luckily a friend that I met through this blog helped me with the cuts. He lives in my city and has a modified Sherline mill with bigger range. Also he is a Sherline dealer in Chile and works on CNC projects and has several interesting posts on his own blog at metaltronics.wordpress.com.

Fresado en Sherline modificado
Milling on the modified Sherline mill.

For the chest cuts, we tested using only a 1.5mm endmill, even for holes (1.6mm the smallest). For future cuts I will use bigger endmills such as 2mm o 2.5mm as in my previous cuts, the 1.5 endmill requires a depth of cut too small (we used 0.2mm) and are more fragile.

Since I am not going to use the original DARwIn-OP electronics (Fit-PC + CM-730 controller), I modified the chest parts to allow mounting an Odroid-XU3, in particular for access to the rear ports and mounting points.

Partes del pecho con Odroid-XU3 y servos de hombros y cuello.
Chest parts with mounted Odroid-XU3 (and USB2AX) and shoulder + neck servos.

The Odroid-XU3 fits without problem, but to mount the USB2AX (interface to servos) I had to adjust the TTL connector to a vertical position.

In the rear, I exposed the Ethernet port, 4 USB ports and a micro-HDMI (with a 15cm extender). Probably I’ll leave only 2 USB ports exposed, removing one connector to allow for more internal USB ports.

Puertos del Odroid-XU3 expuestos
Odroid-XU3 exposed ports.

The upper chest part was modified to mount a 10-DOF, centering the accelerometer chip in the same place where the original CM-730 controller has its own. Additional holes tapped to 2.5mm were added for future components.

10DOF montado
10-DOF mounted on upper chest part.

Because of the change of electronics, a 6 port TTL dynamixel hub is needed to connect the servos. In the rear there is just enough space to mounted.

Hub dynamixel de 6 puertos
6 port TTL Dynamixel hub.