Let's Make Robots!

Wobbly Raspberry Pi Biped

Walks and turns, kicks a ball, and sits down !

Based on a 6 DOF BRAT clone kit from ebay ($50!)

Uses 6 MG995 45g servos:

2 Ankle Servos, 2 Knee Servos, 2 Hip Servos 

4xAA Nimh to drive servos

2xAA to drive Raspberry Pi via a cheap "emergency charger"

All controlled by a Raspberry Pi using servoblaster software PWM and programmed in python (but might move to C if I need the speed)

Still a bit wobbly as I'm not using the knee servos much at the moment.

Its interesting that I can get it to walk with just 4 servos in use - so there's an idea for my next bot ;)

[edit]

My 8 year old nephew Jake thought the bare robot looked boring,

so he drew paper clothes, and added arms and legs:

 

dressed robot

https://www.youtube.com/watch?v=5OQgIfOEktk

also now goes left/right by varying the individual leg's stride length.

I wrote some code for a fast kick:

kicking ball

https://www.youtube.com/watch?v=noObFbkCABU

This runs the knee/hip servos at full speed, instead of slow smoothly interpolated sweeps like used in walking/ leaning

 

E.g.

Servo.hip = 90

Servo.hip= 140 

vs

For sweep in range (90, 140):

          Servo.hip = sweep

          time.sleep (0.01)

I've also moved the battery pack down to the hip for better stability and more torso movement, and can sit down after a long day: 

http://www.youtube.com/watch?v=PEIbgrYKP0I

Next step is to give it some autonomous behaviour (HC-SR04 ultrasonic sensor and/or camera)

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The mini basketball had me wondering where I could get servos the size of cigarette packs.

Its an indoor mini backetball - the servos are regular 45g ones

I think this is the begining of a new breed of robot. The "Pi-ped"!