This is a tutorial for building a single servo motor walker robot using straws, strawbees, one servo motor and a QuirkBot (but any other arduino might work even not so nicely ;P )
Step 1: Material
The basic material you'll need to build this is:
- 14 straws with the same size (or close enough)
- 30 single leg strawbees
- 2 double leg strawbees
- 1 Scissor
- 1 Rubber band
- 1 Servo motor with horn
- 1 QuirkBot
Step 2: Assemble the Legs
We cut the straws all the same size for a practical reason but the inner part of our robot leg is actually a bit smaller so you'll need to cut it to make sure you'll have a 90 degrees angle between the external part of the leg and the "shoulder/hips".
Pay some attention to the strawbees angles and locks but don't be afraid of commit any mistake since it's just a matter of unplug, fix and plug again.
Step 3: Servo Case
This is perhaps one of the most important parts of this robot because if the servo is too lose, it turns itself instead of move the structure.
Making this servo case can be a bit tricky if you never touched a strawbee. If you are having troubles with this one, I strongly recommend to play around and find your own solution (and reply me with it! I'll love to check it out).
To make my servo even more stable in the case, I used a rubber band (I love rubber bands!)
Step 4: Attaching the Servo Horn
Make sure your servo horn is tight enough inside the strawbees holes, otherwise it will slip away.
Also pay attention to put the horn inside one of the straws. This is very important!
If you want to move stronger and faster, screw the servo horn. I recommend to do this as a very final step.
Step 5: Diagonal Axis
This is a trick.
If you want to move 2 parallel axis with a single servo, attach their joints with a perpendicular axis.
Do it as a diagonal axis you'll have a cool inverse rotation, very useful for walking robots in general.
Step 6: Make It Stronger
Triangles. The solution for your weak wobbling structures probably is: Triangles.
For this we'll need 4 extra straws bigger then the first size straws.
Play around with this extra straws to create the best angles and spacing for your robot legs.
Tip: Watch the nature, try to copy animals legs sizes and angles. Fail, rebuild, fail, rebuild again. This is evolution, baby! :P
Step 7: Code It
Upload your code to QuirkBot and check how it behaves.
I recomend this code here:
Tip: Run your code first with the servo horn detached and then attach it to the servo, this will prevent your structure to blow out if it's too strong.
Step 8: Add the QuirkBot to Your Structure
This is where the QuirkBot shines. With any other arduino like board now you would need to add an extra heavy, complex and often ugly solution to make your walker robot carry the board, electronic components and battery while it walks.
Because the QuirkBot is compatible with strawbees, you can just fit it in the structure you already have!
Step 9: Tweak Until You Make It
Play with the angles, sizes, servo speed and evolve your Quirk creature until you get satisfied but mainly:
Have fun! :P