Roamer, the Self Charging Companion Robot




Introduction: Roamer, the Self Charging Companion Robot

About: I am an author and a maker. My current project is Santa's Shop. I'm working on a science fiction type book--more later. @EngineerRigsby

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.


(2) Servo motor, no end stops

Boost converter

500 farad, 2.8 volt capacitor

Lever switch, momentary

photo resistor


Arduino motor shield

Vacuum belt

One amp diode

(4) 4.7 k resistor


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)

Step 1:

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

Step 2:

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).

Step 3:

Add the vacuum belt (tire) the the wheel.

Step 4:

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

Step 5:

Mount the motors to the base using 3mm screws.

Step 6:

Secure the wheel to the motor shaft.

Step 7:

Attach the other wheel.

Step 8:

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

Step 9:

Insert the caster ball.

Step 10:

Place a 3mm screw in the spring.

Step 11:

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

Step 12:

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

Step 13:

Secure the switch holder to the front of the frame.

Step 14:

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

Step 15:

Install a lever switch in the switch holder.

Step 16:

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

Step 17:

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

Step 18:

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.

Step 19:

Place the boost converter on the electronics holder.

Step 20:

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

Step 21:

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

Step 22:

Add the breadboard and wire according to the schematic.

Step 23:

Add the Arduino and motor shield. Secure using Velcro.

Step 24:

Add the eyes and smile to the back.

Step 25:

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.

Step 26:

To keep up with the latest for Roamer, look here.

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