This little robots mechanical principle is based on a traditional toy that lets the robot climb up the string if you pull on it.
Check out this youtube video for the robot in action and watch it being assembled.
Get "Climbing Robot" Merch.
As a modular print it is a nice project for newcomers to 3D printing, as it allows to play with settings from part to part. If a print should fail only little time and material is wasted.
Overall the print does not pose any hard challenges.
Last but not least it is also a great way to recycle your filament leftovers and make it really colorful.
There is a backpack and a hat for this robot here: Climbing Robot Accessories
Besides the printed parts you will need an elastic band and a string.
I used a elastic band as commonly available for textile work. A normal rubber band might work too but is probably not as long lasting. In any case the band can't be wider than 5mm (0.19 in) and thicker than 1mm (0.04 in).
Not everything will work for the string as the correct amount of friction in the robots "hand" is crucial for the climbing action to work.
The model is optimised for a ca. 3mm (0.1 in) or a ca. 2mm string. There are two versions of the clamp available for download. From my experience a coreless braided string works best.
This video has step by step assembly instructions if needed.
If your printer is tuned to produce correct dimensioned parts the robot will friction fit together. Otherwise just use glue or tune up the fit with a file or sanding paper if the parts are too large.
Tuning the clamping mechanism
In general the clamp should clamp just hard enough to hold up the robots own weight. Use a round file to smooth the bottom of the groove the rope runs through in clamp-p1.stl' to remove all the printing striations. Apart from that it's important that the hole through the "shoe" is large and smooth enough to let the rope slide through without friction. A good way to achieve this is to bore out the hole with a fitting drill. I chose a 3.5mm drill for the 3mm rope I used.