Instructables Blinking Robot

This article is about the Instructables-looking blinking robot toy. We have all seen the Instructables robot. This article shows you how you can make a robot that blinks when you move one of its arms.

The first video is 2 minutes and shows you step-by-step photos of this article with music. The second video is only 12 seconds and shows you the robot working.

You can see the circuit image that I will explain in detail in the next step.

Supplies: cardboard, bright LEDs - 3 (you might need one spare), AA or AAA battery holder for two batteries with switch, insulated wires - 10 cm, 27-ohm resistor (if you are using 10 mm thickness LEDs) - low power - 2 (you might need one spare), 1 kohm potentiometer, potentiometer knob, scotch (clear) sticky tape, and masking tape.

Tools: scissors, wire stripper, ruler, pen, or pencil.

Optional supplies: solder, 47-ohm resistor if you are using 5 mm thickness LEDs.

Optional tools: soldering iron, pliers.

I used PSpice student edition version 9.1 to draw the circuit. This software does not have an LED component. Thus I used three general purpose diodes instead.

You can see that the variable resistor is used to increase or reduce the current that is supplied to the LEDs. When the variable resistance is zero the current is maximum. When the variable resistor is 1 kohm the current is minimum and the LEDs are almost OFF.

The only design challenge is calculating the Rleds resistor value.

When the variable resistor resistance is zero Rleds value can be calculated:

Rleds = (Vs - Vled) / (ILED1 + ILED2)

Vs = 3 V and Vled = 2 V. Therefore Vs - Vled = 1 V

For big 10 mm thickness LEDs: ILED1 = ILED2 = 20 mA and ILED1 + ILED2 = 40 mA, Rleds = 1 V / 40 mA = 25 ohms (I chosen the next closest value from E12 series of 27 ohms)

For typical 5 mm thickness LEDs: ILED1 = ILED2 = 10 mA and ILED1 + ILED2 = 20 mA, Rleds = 1 V / 20 mA = 50 ohms (I would choose the next closest value from E12 series of 47 ohms)

For small 3 mm thickness LEDs: ILED1 = ILED2 = 5 mA and ILED1 + ILED2 = 10 mA, Rleds = 1 V / 10 mA = 100 ohms

3 V supply is obtained by using a battery holder that connects two 1.5 V batteries in series.

I used PSpice student edition version 9.1 to simulate the circuit. The current across the LEDs (diodes) is not 20 mA but slightly smaller. However, this is just a minor discrepancy because I did not use the LED component.

You can see that I did not use a soldering iron. I just twisted the wires and sealed them with masking tape and then sealed them with clear tape.

I cut out a piece of cardboard with scissors and made holes for the two LEDs.

I then inserted the LEDs, wrapped them around to make the head, and sealed them with clear tape.

I measured a piece of cardboard and cut it out with scissors. The height of the cardboard piece is 10 cm.

I then cut out a quarter circle shape (second photo), folded it in half, and used it as a reference to cut out the second quarter circle shape (third photo). Because I folded in half the left side and the right side looked the same.

I then placed the cut-out cardboard piece onto the second rectangle (fourth photo) and used it as a reference for my second shape.

Then I joined to front and the back shapes together with sticky tape (fifth photo).

I cut out a 14 cm by 7 cm rectangular shape, cut in the middle two to make two 7 cm by 7 cm shapes, and rolled them into a cylinder to make the legs. I then sealed them with clear tape.

I repeated the previous step for the arms, except that I cut out the two cardboard shapes as shown in the photo.

Before creating a lid for the head I decided to test the robot. It was working.

I put the robot upside down on a piece of cardboard, traced the head with a pen, and cut it out. I attached the lid with clear tape.