Build Your Own Popcorn Strobe
Flashing Circuit Strobe LightSkill Level: Beginner
Assembly Time: 1 Hour
Designer: Joe Klemencic aka "Trowelfaz"
The Popcorn Strobe produces a flashing circuit similar to a strobe light. It is intended to fit inside of a plastic dome that you get from gumball machines.
In order to control the rate of flash simply adjust the potentiometer. This is a great small circuit demonstrating 555 Monostable circuit operation, perfect for creating special effects.
Build Your Own Popcorn StrobeRequired Tools and Components:
100K Trimmer Potentiometer
10K Ohm 1/4W Resistor
4.7K Ohm 1/8 Watt Resistor
10µF Radial Capacitor
5MM White LED
Printed Circuit Board
Soldering iron and solder
12V power source
Vending machine capsule (optional)
Step 1 – Install the LEDsSolder on the 4 white LEDs to positions L1, L2, L3 and L4. Make sure to take note of the orientation, for the LEDs have positive and negative legs. Looking at the back of the LED, the 'straight' segment should align to the straight line on the PCB. The connections to the center of the LED should align to the angled lines on the PCB. The LED outline on the PCB has a shaved corner to assist with alignment.
Step 2 – Test the LEDs after installingTest that the LEDs have been properly installed. Using the leads from a 9V-12V power source, insert the positive cable to the '+' hole on the PCB (do not solder it, just hold it). Next tap the negative lead to the upper leftmost LED (L1) led by the '-' symbol. All 4 of the LEDs should be illuminated.
Step 3 – Soldering the 555 timer chipInsert and solder all 8 legs of the 555 timer. Make careful note of the orientation. The notch in the chip is to be aligned with the notch in the graphic on the PCB.
Step 4 – Soldering the transistorInsert the transistor into position, taking note of the orientation as directed on the PCB. Solder each of the 3 legs and trim to length.
Step 5 – Soldering the resistorsInsert and solder the 10K and 4.7K resistors. Orientation is not important. The 10K resistor (brown. black, orange) is installed just under and left of the transistor (marked R2). The 4.7K resistor (yellow, violet, red) is installed next to the 555 timer next to pins 7 and 8 (marked R1).
Step 6 – Soldering the trim potentiometerAdd the 100K trim pot. This pot is used to control the flash rate. Insert and solder the 100K trim pot according to PCB. It will be located to the right of the 4.7K resistor.
Step 7 – Soldering the radial capacitorInstall and solder the 10µF radial capacitor as directed by the PCB. Take note the positive side of the capacitor is to be aligned with the '+' sign on the PCB just above the capacitor graphic. The negative (striped marking on the capacitor) will go towards the bottom of the PCB. After you are done soldering, trim the leads.
Step 8 – Attach the power wiresGo ahead and fish the 12V power wires through the circle cutout from the underside of the PCB to the top of the PCB. Insert the stripped ends of the wire through the corresponding power holes ('+' for 12V positive, '-' for 12V negative/common). Then solder the wires to the underside and snip the tails.
Step 9 – Attach strobe PCB tothe baseOnce completed you can now attach the built PCB to the dome lid of the vending machine capsule, or any enclosure you see fit. To accommodate the power wires drill a small hole in the back of the dome. Feed the power wires through the hole. To hold the PCB and dome lid together, you may want to tape or hot glue them together.
Step 10 – Finished projectSnap on the clear plastic dome. Hook up the wires to your 12VDC power source and enjoy your strobe action. In order to increase or decrease the flash rate turn the potentiometer.
About the Designer
Joe Klemencic is a Computer Security manager by day and a Holiday Light enthusiast by night. His year round hobby is designing, building and programming lights and circuits for his computer controlled holiday lights display. While Joe is still a novice when it comes to electronics, most of his display elements cannot be purchased in stores, so they must be fabricated by hand. Microcontrollers and electronics play a big part in bringing it all together, and offer a vast opportunity to learn many aspects about electronics while creating art for others to experience.