Page 195 - Robot Builder's Bonanza

164 CONSTRUCTING HIGH- TECH ROBOTS FROM TOYS

Construction Parts Temporary Permanent
LEGO, K’NEX, Zometool White glue ABS plastic solvent cement;
2-part epoxy
MEGA Bloks, plastic models White glue, low- temperature Plastic model- building
(e.g., model cars or airplanes) hot- melt glue (polystyrene) solvent cement;
2-part epoxy
Fischertechnik, most other Low- temperature hot- melt glue ABS- PVC solvent cement;
plastic construction toys 2-part epoxy

• For a strong but less permanent bond, use only very small amounts of solvent cement or
epoxy.
• You can also make nonpermanent bonds by using very small amounts of cyanoacrylate
(CA) adhesive. Super Glue is a common brand of CA adhesive. Apply to one side only.
Remove the parts by giving them a good twist.
• High- temperature hot- melt glue provides a good middle ground between temporary and
permanent constructions. Use sparingly if you wish to disassemble the parts later. The glue
can usually be peeled off.
• Flexible adhesives, such as Shoe Goo or any silicone- based RTV adhesive also make for
strong yet temporary bonds.

Depending on the design of the construction toy, you can also use mechanical fasteners to
hold things together. Drill holes in your LEGO, MEGA Bloks, or K’NEX parts, for instance,
and secure them with miniature 2-56 or 4-40 machine screws and nuts. The plastic is easy to
drill through, and the fasteners can be readily removed if you need to take things apart.

USING SNAP- TOGETHER PARTS TO MAKE MODULES
You’re not limited to using snap- together construction parts just for the body or structure of
your robot. You can use extra or discarded LEGOs and similar construction pieces for making
customized accessories. The snap- on nature of these parts allows you to easily reuse these
accessories for different prototype projects.
For example, you might glue the flat bottom of a standard R/C servo motor to some LEGO
blocks. (It’s okay to use glue here because you’re able to reuse the motor as much as you’d
like. Simply pull it off the LEGO plate when you’re done.) Use the servo motor to
Plate
quickly and effortlessly attach a sensor turret to your base. Just add a bracket and
Servo ultrasonic or infrared sensor on top of the servo, snap the servo into place on the
base, and you’re done.
The same concept works for other components as well, such as compasses,
accelerometers, microcontrollers, speakers, and lights. The idea is to mount the
Bottom view
part to one or more accommodating LEGO pieces, ensuring that everything is
aligned. This allows you to press one LEGO part into the next.
The idea doesn’t stop with LEGO beams, plates, and other parts. You can also use plastic
or metal construction set pieces from an Erector set. One benefit here is that if you make
accessories using these parts, they are easily transferred to full robots once you have success-
fully prototyped the design. For instance, you can permanently mount a short LEGO Technic

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