Picture of Quiz-O-Tron 3000: Arduino quiz contestant lockout system

If you have ever watched a TV quiz show you have probably seen contestants trying to press a button in order to win a chance to answer a question. The contestant’s quick reaction time results in some kind of light and/or sound indicating victory. This is a practical way to choose the next focus of the game’s activity and it adds a bit of excitement to the process. So when my company's holiday party planning committee decided to have a trivia contest I decided to build a quiz contestant lockout system to add an extra dimension of fun to the festivities. This would help the planning committee’s mission of creating some entertaining activities for the event.

The minimum requirements were to have a system with multiple buttons that contestants press for a chance to answer a question. The first one to press the button would lock out the other contestants. The system would need to have a simple way to quickly identify who pushed their button first. And finally the system would need to be reset for the next round.

Considering the venue of the holiday party (an upscale wine bar) I felt that the contestant buttons would be one of the most important features. They needed to be hefty and able to withstand abuse by hoards of “beverage enhanced” partygoers. Fortunately I had encountered a really good contestant button candidate while visiting the local office supply store. Staples’ “Easy Button”, as made famous in their humorous ad campaign, is available in their stores. This device is a palm sized button modeled after the one seen in the Staples commercials. It is battery operated with a speaker that says “That was easy” when the button is pressed. It is well made and the ideal shape and size for use by a quiz contestant.

Given that the button is a self-contained electronic device I was confident that I could open it up and extend the switch functionality to the system I was building. The $5 cost was reasonable for the quality of the item. Plus Staples is donating the proceeds from the sale of their Easy Buttons (up to $1,000,000.00) to the Boys and Girls Clubs of America. So, planning to build a system that would allow four contestants to play at once, I grabbed four of these and left the store feeling good about my purchase for a number of reasons.

Now that I had the contestant user interface worked out I needed to decide how to implement the system functionality. Due to time constraints this needed to be done with material I already had. This turned out to be an Arduino Uno, one of Adafruit’s Proto Shield kits and some miscellaneous parts. This intro section includes a picture of the completed system that I dubbed the “Quiz-O-Tron 3000” (QT3K for short).

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lamandoh223 years ago
Good morning,
Please can you give an approximate cost in dollars of this project. Also, you only listed where the arduino and the shield can be purchased, can I assume that everything else is available at radioshack. This is a really impressive instructable and I admire the fact that you've laid it out so elegantly. Thank you for your time.
I bet you can get this cost down significantly. I used large pushbutton timers I got from Electronics Goldmine for $1 each and gutted the inside and replaced with my own pcb or perfboard. Since the pushbutton timers had a large plastic body I didn't need a project box for each button.

I mocked up the project using my arduino but then transferred the 328 to a perfboard arduino that cost about $7.

Bought 1 project box for the brains at radio shack for $3.

A handful of LEDs.
A spook of telephone wire for the hookups between the buttons and brains. ~$7.
Also you could go cheaper on the connectors (or go without) between the buttons and base station.

I think that was it. So you could get away with spending possibly under $30.

Not too bad. When I was trying to find a system like this for some fun school practice quiz games the cheapest I could get was just over $50.00. And that was searching the net, to find the best price and trying to convince them to give me a teacher discount.

RoysterBot (author)  ChrisPrince3 years ago
This is great advice. Do you have details on the perfboard Arduino that you used? Thanks!
For anyone else that wanted to find it too:
RoysterBot (author)  RoysterBot3 years ago
I found your Instructable on the Arduino perfboard. Thanks again!
RoysterBot (author)  lamandoh223 years ago
Hello! Thank you for your kind works. The cost was about $180-$200 US. This is mainly becase I used some expensive metal cases to mount the Easy buttons on. The Arduino and Proto Shield can be purchased from Adafruit Industries. Their web site is located here...


jhahn58 months ago
How about a wireless version?
RoysterBot (author)  jhahn58 months ago
Great idea. I will see if I can add that to the next version.
Help me I checked my drafts and instructables is giving me credit for your ible!

There is really nothing I can do about that. You should report that to Instructables help support.

I was impressed with the lockout system. I have been trying to find one for some time now. I am only a weekend warrior in Electonics and could not build it myself. My question is - where can I buy one or find someone who could build it for me. I have 5 grown kids and between them 12 grandkids who all come over for game night. I would love to be able to use it so that each of the 5 families could compete against each other. Thanks
ashough5101 year ago
Hey, just want to start by saying thanks for all the work you've put into this Inscrubtables =D. Been working on the shield and was wondering if there was a schematic for how the shield is pieced together, the construction of the circuit aren't the easiest to follow based off of the step 3 pictures. Thanks a lot.
RoysterBot (author)  ashough5101 year ago
Step 5 has the schematic for the shield circuit. Note that this schematic shows the circuit for one button/LED pair. So this circuit is implemented 4 times on the shield for this project. How you layout the components on the shield is not critical as long as you make the proper connections to the Arduino pins. Depending on your soldering skills you might want to allow more space between components on the shield than I did. In hindsight I should have done this so the part layout on the shield would be easier to see in the picture. The components on the shield I did are about as densely packed as they can be. I did this to conserve space on the shield in case I wanted to add new features. When I have time I will try to make a shield with some step-by-step photos and more detailed instructions. Thanks for your feedback!
nurulhuda1 year ago
can we do it for 50 contestan
wewss2 years ago
hello sir,
can i get the pdf of this project ?
thanks !
RoysterBot (author)  wewss2 years ago
Yes. When you log into instructables there will be an option to download all steps in one PDF file.
Daanii2 years ago
Okay, I figured out the problem. On the last picture above, there is a capacitor in the lower left corner, right on top of the letters that say "T11A39." I had to detach one leg of that capacitor. Then things work. (Notice that in some of the pictures that capacitor has been removed.)

In short, you need to solder two wires on, cut the trace to the resin blob, and remove or detach the capacitor. Then the board works as a simple switch.
Daanii2 years ago
I tried the hack with the new board, and attached the wires to the two sides of the switch pad. But I can't get the switch to work. I'm stumped.
nmvb2 years ago
Would it be possible to make this just with push buttons instead of a easy button?
RoysterBot (author)  nmvb2 years ago
Sure. Any momentary contact switch would work.
cucoons2 years ago
Were any of you able to make the switch work on the new board?? I just ran into the same problem today with no luck =(
RoysterBot (author)  cucoons2 years ago
I have updated section 2 of this instructable with details on how to get the new version of the Easy button to work. Let me know if this helps.
ok, i REALLY need a schematic, and i need it by tommorrow! or please tell me whats connected where. and what resistors are those in the front
RoysterBot (author)  TheParacorder2 years ago
Can you be more specific? There are two schematics included in the instructable that show the value of all resistors and their respective connections.
ok i have a problem... im not sure what.. for box 1 where does led + input go to?
RoysterBot (author)  TheParacorder2 years ago
If you are building the LED flasher circuit (STEP 4) to put inside the button box then you power the circuit with the LED+ and LED- connections. These connect to the LED+ & LED- connections coming from the Arduino shield (STEP 5). If you are not implementing the LED flasher circuit then you can ignore the LED+ & LED- connections from the shield to the flasher circuit.
im only doing 3 contestants... can you please edit the program for me to only have 3 buttons? i need it asap
RoysterBot (author)  TheParacorder2 years ago
Since you'll only be using 3 sets of pins to work with 3 buttons, just change this...
int maxPins = 4; // Max number of pin sets
..to this...
int maxPins = 3; // Max number of pin sets
...and you should be good to go.
for the temp button did you solder the leads to the terminals of the button?
because i dont want to go spend alot for easy buttons, is it possible to run a temp switch (one similar to a arcade game button) instead without inserting any resistors?
RoysterBot (author)  TheParacorder2 years ago
You can use any kind of switch you like. A normally open, momentary contact, push button like on an arcade machine is ideal.
alright thanks.
nyckid3 years ago
Nice setup! I would suggest using Cat5/Cat6 cable instead of serial cables since you're only using 4 wires. There's still room for expansion, but if you set it up with RJ45 jacks and use standard patch cables you can extend the range very inexpensively. :-)

RoysterBot (author)  nyckid3 years ago
Thanks Ryan!
heato3 years ago
Awesome project RoysterBot! I am attempting to build one, but I think I have run into a stumbling block. I decided to try telephone cable as the interconnects, as it has 4 conductors and handy plugs at both ends. I think this is my problem though, I test the contestant boxes with a 9V battery & no cable and they work fine, but at the end of the cable I get no response. Do you think I am having this problem because of voltage drop on such a small wire? Could you post the size of wire that you used? Any help will be welcomed. Thanks again for sharing this fun project.
RoysterBot (author)  heato3 years ago
The wire I used to connect the button boxes was about 20 or 22 gauge. Telephone wire should be able to handle the 9V. Have you tested the voltage you're getting at the button box end when you connect the battery to the wire and confirmed the proper polarity?
Hello to everyone! My project was a success! The Telephone wire connects worked fine, and was a quick and easy solution with ready made cables. My problem was in my layout or schematic. Had I plugged in all of my button boxes, I would have discovered my issue much sooner! It seems that box 1 & 4 worked fine, but box 2&3 the flashing lights were crossed. When the contestant button on #2 was pressed, the lights would flash on #3! (and vice-versa) I laid this out as closely as shown in the pictures in this tutorial, but somewhere there was a mix-up. At that point there was two ways of solving the problem, one would be to remap the code in the sketch, two would be to switch the wiring on the shield. If you run into this problem yourself, pick the solution that you feel most comfortable with. Have fun and good luck stumping your contestants!
RoysterBot (author)  heato3 years ago
Congratulations and thanks for posting!
msamples7953 years ago
will do thank you very much for your quick response
phunt463 years ago
I see the board model you used is the CA68-03C for this illustration. Have you came across the same make but board model T11A39?
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