Game Show Buzzer

It was time for our annual office Xmas party and my boss wanted to do a Family Feud type game. He asked me to build a simple game show buzzer like on the show. I received an adequate budget but I only had about a day to complete the project. With only a vague concept in my head, I drove to a surplus electronics shop. Since I had very little time I was determined to buy everything at once and there was definitely no time for mail order. Below is the final result. There are two large 2″ illuminated arcade pushbuttons and two Xeon strobe lights. The first button pressed activates the corresponding strobe and locks out the other. Pressing the buttons also switches a loud buzzer. The surplus blue case was a bargain and just the right size. It didn’t have any front or back covers, so I cut 2 pieces of acrylic, which also serves to hold some XMAS graphics.
Game Show Buzzer
Here is a Pov-Ray 3D model of the circuit. I chose an Atmel ATTiny 45 microcontroller because I had several in my parts bin. I didn’t need the 4K but I was out of ATTiny25 chips. The small 5V Omron relays are used to control the 12V Xeon strobe lights.
Buzzer Board Rendering
Here is a shot inside the completed unit. A 12V DC laptop adapter powers the button lights, strobes, LED’s and feeds the circuit board which steps down to 5V. The adapter was too expensive, but it was all I could find that would fit. I need 110V AC inside the case to fire the buzzer.
Case Interior
Here is the Cadsoft Eagle drawing of the 3.5″ x 1.5″ board. One bridge was necessary.
Buzzer Board Drawing
The completed etched circuit board. Here are my etching notes in PDF format and this is a great website that further details the process.
Buzzer Board

I tried several low voltage piezo buzzers, but they all sounded like smoke alarms. I wanted mine to sound like something on TV. I finally found an ideal sounding 2″ metal buzzer. Unfortunately, it was 110V AC which complicated my design. I considered building an MP3 circuit to use the actual sound from the TV show, but I just didn’t have the time. Fortunately, the surplus store had a great deal on solid state relays. The Crydom SSR below can easily handle the 110V buzzer and can be driven directly from an AVR pin, unlike the mechanical relays above which require a resistor, transistor and diode.
A/C Buzzer
Here is a shot of the back of the case. I added a fuse just to be safe. The aluminum screw on the top secures the buzzer. The rotary switch disables the buzzer and the super bright violet LED which illuminates the inside of the case. The small illuminated red pushbutton resets the game.
Case Rear
The game show buzzer was a big hit at the party. It worked flawlessly and everyone liked the lights and sound. One of my colleagues actually took the buzzer home for the holidays to play games with her family.


Downloads:

Buzzer source code – Version 1.00 – Released 12/27/2007 – For ATTiny45
Buzzer circuit Eagle files.


Parts List:

DescriptionQtyCost
Blue Project Enclosure1$ 4.50
Solid State Relay 240 VAC 18A 3-15 VDC19.50
120 VAC 2" Metal Buzzer11.50
4" X 6" X 0.062" Single Copper Clad Board12.50
High Reliability 8 Pin IC Socket10.50
Two Position Rotary Switch DPDT11.25
Black & Red Plastic Knob 1/4" Shaft10.75
12 VDC 3.33A Switching Power Supply19.75
12 VDC Lighted Pushbutton 2" Momentary Green 14.75
12 VDC Lighted Pushbutton 2" Momentary Red14.75
12 VDC Strobe Xenon Flasher Green18.95
12 VDC Strobe Xenon Flasher Red18.95
Insulated Female Crimp Terminal 1/4" Red10.10
Insulated Male Crimp Terminal 1/4" Red1 0.10
Insulated Female Crimp Terminal 1/4" Blue40.10
Heat Shrink Tubing 3/32" x 4' Red11.25
Heat Shrink Tubing 3/32" x 4' Black11.25
NPN TO-18 2N2222A Transistor20.50
Rectifier Diode 1N400120.07
Terminal Block PCB 2 Position Green10.45
Voltage Regulator 5 VDC 500mA10.50
Electrolytic 100μF 25V Radial Capacitor10.20
Electrolytic 10μF 16V Radial Capacitor10.10
Resistor 1/4 Watt 1.5K Ohm20.05
Resistor 1/4 Watt 10K Ohm10.05
Resistor 1/4 Watt 560 Ohm10.05
Resistor 1/4 Watt 680 Ohm10.05
2 Pin Connector with Header .10"10.70
4 Pin Connector with Header .10"11.30
Jumper for .01" Header10.10
Violet Super Bright LED11.39
Screw Cap Panel Mount Fuse Holder11.99
6A 250V 1¼x¼" Slow-Blow Fuse (4-Pack) 12.99
Atmel ATTiny45 (Tiny25 also works)12.13
5V Relay Omron G5V-122.33
Aluminum Screw1
Spanner Screw, Split Washer, Fiber Washer & Nut1
Socket Cap Screws4
Motherboard Screws4
Lucite 11" x 2" x 1/8"2
Illuminated Red Alarm Pushbutton Momentary1
AC Power Chord1
AC Right Angle Power Plug1
Insulated Female Crimp Terminal 1/4" Right Angle Red2
Insulated Female Crimp Terminal 1/4" Right Angle Blue6
Cable Ties12
Assorted Wire1
Double Sided Velcro Tape1
Strain Relief for Power Cable1
Ring Crimp Terminals Red2
Additional Heat Shrink Tubing Misc Sizes1
.01μF Capacitor Ceramic 50V Axial1
5x2 Pin Header .01"1
2x1 Pin Header .01"1
Etching Chemicals & Supplies1