Tracked robot - concept

first of all i would like to say hello to the LMR crowd and thank fritsl for creating this nice place where we can all share our robot experiences and have fun.

that being said let's talk about robots.

i used rhino3d to design the frame which is based on the tamiya twin-motor gearbox(#70097) and the track&wheel set(#70100).

the parts for the frame are cut from a sheet of 3mm MDF with the help of my robot slave(cnc router). they fit together with tabs and slot and are glued with wood glue.

the electronics consist of

the brains: atmega168 - bascomavr

motor driver: L293DNE

servo: hextronik HXT900

sensor: sharp GP2D12

power: 2cell lipo 7.4v and LM2940 5v 1A low dropout regulator

and are put together on a perfboard.

more to come...

With the L293D’s pin

With the L293D’s pin compatible cousin, the SN754410 (which is more powerful), I find that the Tamiya gearbox motors can cause the driver to heat considerably, almost to the point of thermal failure. Without a PTC or fuse, the chip will fry for sure. Add a heat sink also if you can.