No-Solder, Funny Robot in Minutes (Bristlebot)

Summary:
Build a cheap robot with no soldering, no programming, and no mechanical work. It is built on a dishwashing brush. To move forward, it will use the vibrations transmitted asymmetrically by the skew of the bristles.

I saw such a robot at the robotics festival of the Swiss Federal Institute of Technology. I first thought it had a propeller, but soon understood it was working with vibrations.

Credits:
Credits of this wonderful idea must be given to Pascal Peitrequin, explaining how to build one on http://www.expo-robots.net/rob-brosse1.html .

My only and very modest contribution is to show a construction requiring yet less tools and materials.

UPDATE: the no-solder no-programming idea came to me from the No-sew duct tape zipper pouch, a sweet project.

UPDATE: Pascal Peitrequin told me his contribution was to use a dishwashing brush, after seeing bristle bots made with toothbrushes. (a bristlebot by evilmadscientist)

Data Sheet:
- Cost: almost nothing, all should be found in a household (more or less)
- Energy: 2 x AA (or AAA) batteries
- Autonomy: hours
- Propulsion: vibrations (sonic ?)
- Actuator: small electrical motor, no reductor needed (the highest RPMs, the better)
- Speed: between snail and turtle
- Software: none. Open-loop. Not even one neuron. Can we still call it a robot ?
- Limitations: won't wash your dishes (finally, lot more neurons are required for this !)

Materials:
- electrical cable connectors (only one needed)
- one 3 to 4.5V motor, possibly from a scrap toy
- two zip ties
- insulated hard wire (new toys use a lot of these, to be attached to their packaging)
- 4 x paper clips
- 1 x spare dish-washing brush head

Important note on the brush head
- It is extremely important that the bristles have an average skew. Otherwise the vibrations won't be asymmetrical in average, and the robot will not advance.
- If you don't find a spare brush head, use a brush and saw the handle away.

Tools:
- zip tie tool (optional)
- screwdriver
- cutter
- adhesive tape
- flat nose pliers
- diagonal cut pliers

Bend one end of each clip as shown on the pictures below. Use the flat nose pliers to get these results.

Tape each clip to each end of each battery. Apply a little pressure to insure electrical contact.

The clips may not touch each other.

Tape the batteries as shown. The angle of the paper clip already gives some expression...

Will be more firmly attached in a next step.

Now we will connect the + pole of one battery to the - pole of the other.

Cut some wire to needed length (not too short) and remove insulation at each end. Bend the ends tightly as shown.

Insert each end as shown.

1. Remove the insulation plastic from one cable connectors, and tighten it to the motor axis. This is what will produce the vibrations.

2. Cut one small cable. Strip half an inch of insulation to both ends (use a cutter with extreme caution, then pull the plastic away with your teeth).

3. Bend one end.

4+5. Insert the bent end into the hole of one motor's connector. Hold at the connector and twist the cable.

Repeat 2 to 5 with another longer cable.

6. strip the insulation at opposite sides of both cables, and bend the ends.

Now bind the brush, the batteries and the motor using the zip ties and the tool.

Connect the shorter cable to the nearby paper clip.

As promised, no special pieces are required, so we'll build a poor-man's on-off switch.

Bend the longer cable to form a hook to be snapped into the paper clip. Don't expect snap noise however.

Closing the circuit will make the motor vibrate.

Even with no decoration, it looks like a funny little animal !

It best crawls on a flat surface. On paper at best. Or on a plate, to circle forever...

(oops quite shaky videos, maybe I should transcode them ?)

You can:
- decorate it
- add LEDs
- etc.

You can also (in full violation of the simplicity and no-solder principle):
- use a battery holder
- use a switch
- solder the ends

Now build your own one and have fun !!!