Introduction: Batty


Batty consists of a bat that lights its eyes and flaps its wings in the presence of light. Its first application is as a decorative element for Halloween. However, it could also be used as a mechanism for room scape by adding some message on the wings. So, when they open the clue can be read.


Referring to the components, Batty consists of two red LEDs, a servomotor and a photoresistor. It also has all the necessary components to assemble the circuit such as resistors, jumpers, Arduino board, and a PCB board.

The PCB board is a test plate with holes in which electronic elements and cables are welded to build circuits.

The Arduino board is a micro-controller that enables the performance of different actions through programming a code. In this case, it assesses the intensity of light and does the order of moving the wings and lighting the eyes.

Jumpers are the conductor cables used to connect the different parts of the electronic circuit.

Resistors are electronic components used to oppose the passage of electric current in an electronic circuit. They are necessary to prevent the passage of a large electric flow that could burn the components.

A servomotor is a special type of motor that allows the control of the shaft position at any time. It contains a decoder that converts mechanic movement into digital pulses. These are read by a motion controller that allows the rotation of the shaft. In the project, the servomotor, bring about the wings beating.

The photoresistor is an electronic component whose resistance decreases by increasing the intensity of the incident light. This means that it can evaluate the amount of light contained in the environment.

Finally, LEDs are Light-Emitting Diodes. In other words, they convert the electrical current that passes through its chip in light.

A step by step guide for reproducing the project

The Batty project is built on three fundamental blocks: the prototype, the electronic components and the corresponding programming code.


Batty is a set of easy-going materials, such as:

/Body: Porexpan

/Ears: porexpan

/Wings: eva rubber

/Legs: eva rubber

/Bow tie: eva rubber

/Eyes: Red LEDs

/Box: cardboard

1/ With hot silicone, the ears stick to the body.

2/ Then, the porexpan is painted with black spray.

3/ With a drill, two holes are made in the body with a diameter smaller than the diameter of the LED. These will be the eyes.

4/ With a small piece of insulating tape, both legs are insulated.

5/ Each leg of the LEDs is welded to a conductive wire. The same happens with the photoresistor’s legs.

6/ Carried out this step, the LEDs are introduced and fit into the cavities previously made with the drill.

7/ The wings are cut from a previously manufactured paper pattern. The same goes for the bow tie and the legs.

8/ Using four needles the hinges that join the wings to the body are made.

9/ To the structure of porexpan is added a wooden bar that sticks to the back of the body. Its only function is to raise the bat.

10/ To move the wings, two fishing lines are used, which pass through them and are attached to the motor by simple nuts.

11/ A cardboard box is made to store the electronic components that make the toy up. In this case, from an A3 sheet of black cardboard and with the help of a sketch, the different parts of the box are cut with a laser machine. Subsequently, each of the parts are glued with hot silicone.

12/ Finally, all the electronic components of the circuit are soldered to a tin plate to ensure a better connection of them and therefore a better functioning of the system.

/Electronic components

These are the electric components used:

/1 PCB board

/2 red LEDs

/4 resistors

/1 photoresistor

/1 servo motor

Following the connection instructions of each component, the electronic circuit is formed on the protoboard. Consequently, two LEDs will be connected with their respective resistors, a photoresistor with their respective resistance and a servo motor.

It is recommended to connect an additional power source to the circuit that provides more power to the system.

/Programming code

The corresponding programming code is written to carry out the activity previously explained.

A short reflection as a conclusion

Batty is a project that, through simple electronic components and programming code, allows everybody to build a funny Halloween toy for children and adults.

Initially, a stepper motor was used to develop the action of flapping the wings of the bat in the presence of light since it was supposed the motor would provide greater precision to the system. However, after implementing it, it is noticed that the speed and the angle of rotation it provides are insufficient for the proper functioning of the bat. Thus, it is decided to have a servo motor that, although the power is lower than that of the stepper motor, provides a wider turning angle.

Step 1: 1/ With Hot Silicone, the Ears Stick to the Body.

Step 2: 2/ Then, the Porexpan Is Painted With Black Spray.

The most important thing is the Spray to be waterbased! Othewise the porexpan will be damaged.

Step 3: 3/ With a Drill, Two Holes Are Made in the Body With a Diameter Smaller Than the Diameter of the LED. These Will Be the Eyes.

Step 4: 4/ With a Small Piece of Insulating Tape, Both Legs Are Insulated.

Step 5: 5/ Each Leg of the LEDs Is Welded to a Conductive Wire. the Same Happens With the Photoresistor’s Legs.

Step 6: 6/ Carried Out This Step, the LEDs Are Introduced and Fit Into the Cavities Previously Made With the Drill.

Step 7: 7/The Wings Are Cut From a Previously Manufactured Paper Pattern. the Same Goes for the Bow Tie and the Legs.

Step 8: 8/ Using Four Needles the Hinges That Join the Wings to the Body Are Made.

Step 9: 9/ to the Structure of Porexpan Is Added a Wooden Bar That Sticks to the Back of the Body. Its Only Function Is to Raise the Bat.

Step 10: 10/ to Move the Wings, Two Fishing Lines Are Used, Which Pass Through Them and Are Attached to the Motor by Simple Nuts.

Step 11: 11/ a Cardboard Box Is Made to Store the Electronic Components

A cardboard box is made to store the electronic components that make the toy up. In this case, from an A3 sheet of black cardboard and with the help of a sketch, the different parts of the box are cut with a laser machine. Subsequently, each of the parts are glued with hot silicone.

Step 12: 12/ Finally, All the Electronic Components of the Circuit Are Soldered to a Tin Plate to Ensure a Better Connection of Them and Therefore a Better Functioning of the System.