(I´d specially like the last part...)
Hi All,
this project could be a bit out of scope here but this is also a recycling project. I used an old Ardupilot board and 3 old servos to construct this robot... And there is also a nice story behind this project:
Some weeks ago, my daughter (4 years old) said me:

"...dady, you are always playing with your flying robots, when are you going to construct a robot for me?"
You can imagine my face, so I started this mini project for her...

I used a very simple and minimalistic hexapod setup (only three servos for six legs). I had used this typical setup long time ago at University but this time I tweaked a bit the design playing with the geometry of the legs, the body and the position of the center of gravity to let it do some funny movements like seat, jump, dance, some acrobatics...
I added also an IR distance sensor for automatic obstacle avoiding and two eyes (LED´s)
This robot has also a simple behaviour scheme (in autonomous mode). The robot becomes "tired", "bored" and "happy" and you can interact with him. The eyes also show different patterns depending on the state of the robot
The robot has three modes:
-Manual Mode : I used the HW mux in the Ardupilot board so you directly control the three servos with your Tx. Make this "thing" walk is a real challenge, you need to sinchronize your movements, but once you have mastered you can do a lot of fun movements!! (like in the video)
-Assisted Mode : You control the robot like an RC car (2 channels). The walk and turn movements (sequences) are executed by the controler, so if you move the stick forward, the robot start to walk forward, if you move the stick to the right, the robot turns to the right... the speed and turn amount are proportional to the stick.
-Autonomous Mode : In this mode the robot starts to walk avoiding obstacles with the IR sensor. The robot will become tired so it start to move slowly until it is so tired that take seat. When the robot becomes bored it start to call your attention. If you bring your hand over it becomes happy, jump and continue walking... Enough to entertain the kids :-)

Size of body : 12.5cm x 6.5cm
weight : 110 grams
Main board : Ardupilot (Atmega328)
Battery : 2S460 with external 5V regulator
Servos : 2x mini servos (HS81), 1x 6-9gram servo
IR sensor: GP2Y0A21YK


The body of the robot is constructed with a carbon & 1.5mm balsa sandwich. The legs are 2mm carbon rods and you will need some hinges for the front legs. I used a 6gram micro servo for the middle legs (that balances the robot) and two 16 grams servos for the rear legs (that connects also to the front legs with 1.5mm rods).
I started a simple build log document with more photos here : Build Log
The project was developed with Arduino. The code is very simple, so there´s a lot of room for improvements. Source code: ArduSpider.zip

My daughter also put a name to her robot: Sara, so codename for this project is Sara.
In the last family meeting (this Christmas) this robot was the "star" and look the kids playing with the robot is priceless...

Happy new year to all!


Views: 18191

Comment by Jose Julio on January 10, 2011 at 1:51am

Thanks to all...

I am happy that you enjoy the video, I spend probably more hours editing the video than developing the code ;-)

@Chris, there are some commercial hexapod kits, but most of them are expensive and complex with 2 or 3 servos per leg (that is 12 or 18 servos in total) and there are some simple kits but don´t have the funny movements... the key of this project was to take a simple setup with only three degree of freedom and take it to the limit.


Comment by Sandro Benigno on January 10, 2011 at 3:19am
Here goes an example about those expensive hexapod that Jose are talking about:

Phenix Hexapod from Lynxmotion ($978.42 per kit): http://www.lynxmotion.com/c-117-phoenix.aspx

I can't imagine the inverse/forward kinematics complexity and it's crazy matrix transformations to achieve this soft movements: http://www.youtube.com/watch?v=NUMGpDTm59w

Comment by Juan Enrique Martin Boix on January 11, 2011 at 1:57am

Ja,ja,ja.... curiosity almost killed the cat.

The frame is not so tricky to made but one needs some experience with wrapping carbon or other fiber to reinforce the joints .If there is enough interest,we can design one based on helis ball joints and some thin pcb´s .The real trick here is power to weight and CG.  Jose´s construction is ultralight ,maybe one can sacrifice some weight with better servos but then beefier joints and legs would be needed to avoid doctor bills.

Comment by Jose Julio on January 11, 2011 at 4:11am


@Juan Enrique help me to construct the legs of this robot. The trick to bend the carbon rods is yours!!

What is your idea with the helis ball joints?

Comment by Juan Enrique Martin Boix on January 11, 2011 at 4:49am

Sure ,I don´t remember this one :)))))


Comment by robert bouwens on January 11, 2011 at 2:23pm

there is interest in building this for my daughter as well :)

here birthday is in may - should be possible to build untill then, isn't it?

more details are very helpfull and welcome.



Comment by Jose Julio on January 12, 2011 at 1:38am

Hi Robert,

have you seen the build log? I will try to improve the document with more information... If you need help in some particular step, let me know...

Some suggestions : If you don´t want to do the carbon&balsa sandwich for the main body, you could do easily with a thin PCB or even with plywood. Legs are not so complicated...

And yes, you have lot of time until May...


Comment by robert bouwens on January 12, 2011 at 10:52am


i did over look that link ...


Comment by Jose Julio on January 14, 2011 at 3:10pm

Incredible!!, this project has been inserted in engadget.com : http://engt.co/h6wP1o


Comment by Andrew Hooper on January 14, 2011 at 8:11pm

really cool. Im in the process of upgrading to an APM so will have the AP spare and looking for a new use :)



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