Making a hexapod robot !

Posted by Happy Hippo on 8/22/2011 09:12:00 pm

I decided to make a basic robot over the summer, here is what I got :) Work in progress!

Watch in HD ! Turn on annotations to see updates!

List of components that I bought on ebay (note: wait time can be more than 1 month! ):

  • Axon 2: http://www.societyofrobots.com/axon2/
  • Serial Bluetooth RF transceiver module with backplane
  • 20x micro servos SG9 (but they are not very good quality: very difficult to attach servo head, wobbly, noisy), rated at 7.2V
  • 2x 1800mAh Li-Ion batteries, NB-2LH, sold only on ebay with so high mAh. And a charger .One battery stopped working today :( My total current was peaking at 4A, so each battery was getting about 2A (maximum, or ~1A average). So I will look for a better solution.
Update: I decided to use 3 of these Li-ion batteries in parallel to reduce the load on each and improve mAh. So far it has been working fine. Even with maximum stress (running :)
  • 50x self tapping screws,cross head, 1.7x5 mm or 2x6mm, try to find with pointy end (not flat). http://tiny.cc/quqq3

AVR studio 5 direct download link:

McUber download page: http://www.yetasoft.com/products/mcuber/

Note: if McUber gets stuck on "Retrieving Ports" message, then you need to associate JAR file with JAVA properly, by downloading JARFIX: http://www.softpedia.com/get/Others/Miscellaneous/Jarfix.shtml

Webbotlib 2 download: http://sourceforge.net/projects/webbotavrclib/files/Version2/

Project Designer download: http://webbot.org.uk/iPoint/ipoint?Link=4&LinkType=External

WinAVR download: http://sourceforge.net/projects/winavr/files/WinAVR/

Hyperterminal for windows 7 64 bit (and other) http://www.mediafire.com/?m281qazx3sexpw8

Assembling components:

  1.  Three batteries are needed to reduce the load on them. But a tiny bit more space is needed on the bottom of the base for three batteries, so the wooden pieces that are inserted between two disks should be maybe 0.5cm more.
  2. A much easier way to make battery mount is to remove a thin wire with metallic end from a futaba head, then make a small hole in the battery cover (that comes with the battery), pull that wire through with wire going 1st. If the hole is small enough, it will hold the metal end nicely.

3.  Outer leg wooden part (thin end pieces) are not quite  proper for this robot, they are not strong enough and make servos use a lot of power :(  I suggest  to make round end pieces, with wider and thicker wood. And attach to the servo perpendicularly, with screws. (alternatively design all parts in a 3D program and print on a 3D printer)

4. Those cheap e-bay servos are not very good.. they are working, but not accurate at all. The plastic disk is very weak, and it wobbles. I'll try to attach some other plastic parts and see it it's going to help. It's better to pay a little bit more, but get better built servos.

5. It is also very convenient to drill a hole to access the screws which hold servo "head" in place, because a LOT of adjustments will be required.

First steps!

I will upload walking hexapod video and more source code, as soon as I figure it out :)
Thanks for watching :)

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