Roamer, the Self Charging Companion Robot

Initially, set Roamer on a charging station. She will wander around, feed herself and rest at night. The next day, she’ll do it again.

The charging station is merely a metal plate and a pole with metal foil attached to a bench power supply.

To me, a personal companion robot should have the functionality of an ant or better: no programming, setting controls or recharging batteries.

Roamer can run about 20 minutes between charges. A charging station can be constructed quickly. The station is simply an energized floor plate and energized bump rail. A spring on the bottom of Roamer contacts the floor plate and Roamer’s front bumper contacts the bump rail. The floor plate and bump rail are energized by a bench power supply set at 9 volts dc with current limited to .8 amps. When Roamer makes contact with the bump rail, she turns off her motors and evaluates the voltage between her bumper and spring. If the voltage is greater than 2 volts and less than 8.5 volts, she sits and waits until the voltage rises to 8.5 volts, then she backs up and is on her way--unless it is dark.

Supplies

(2) Servo motor, no end stops

Boost converter

500 farad, 2.8 volt capacitor

Lever switch, momentary

photo resistor

Arduino

Arduino motor shield

Vacuum belt

One amp diode

(4) 4.7 k resistor

breadboard

aluminum duct tape

spring, 5.5 mm x 38 mm

sheet steel

Bench power supply

Wire, solder, 3mm screws

3d printed parts (files available in this Instructable)

Start with the servo motors--I selected metal gear servos that do not have end stops. Remove the circuit board.

Extend the wires that connect to the motor and reassemble the servo motor (remember, this must be a "no stop" servo motor, otherwise, you have to get rid of the mechanical end stop).

Add the vacuum belt (tire) the the wheel.

Secure the servo horn to the wheel using 3mm screws.

Mount the motors to the base using 3mm screws.

Secure the wheel to the motor shaft.

Attach the other wheel.

Fasten the base for the caster ball at the rear of the frame.

Insert the caster ball.

Place a 3mm screw in the spring.

Drill a hole in the base and put the screw through the hole.

On the other side of the base, attach the pickup wire.

Secure the switch holder to the front of the frame.

Attach aluminum duct tape to the front bumper. Tape a wire (so that it connects to the foil electrically) to the bumper.

Install a lever switch in the switch holder.

Attach the bumper to the switch holder using 3mm screws.

Place the board/capacitor holder onto the frame. Glue together (or lightly melt using a soldering iron).

Attach two capacitors to the rear part of the frame using Velcro strips. Place the third capacitor (horizontal) in the center of the red piece.

Place the boost converter on the electronics holder.

Secure the charge plate pole to the charge base using 3mm screws.

Place foil tape on the pole--not touching the base.

Add the breadboard and wire according to the schematic.

Add the Arduino and motor shield. Secure using Velcro.

Add the eyes and smile to the back.

The spring and bumper are contact points for the charging system. Attach the positive lead from the power supply to the pole of the charger assembly. The sheet metal base should be attached to negative. The power supply should be set to 9.1 volts dc with a current limit of .8 amps.