Planet Arduino

Planning a game of Hacker Jeopardy at your next meetup? You’re going to want some proper buzzers to complete the experience, but why buy when you can build? [Flute Systems] has released an open source DIY game buzzer system based on the Arduino that will help instantly elevate your game. Certainly beats just yelling across the room.

The design has been made to be as easily replicable as possible: as long as you’ve got access to a 3D printer to run off the enclosures for the buzzers and base station, you’ll be able to follow along no problem. The rest of the project consists of modular components put together with jumper wires and scraps of perfboard. Granted it might not be the most elegant solution, but there’s something to be said for projects that beginners and old salts alike can complete.

Each buzzer consists of an Arduino Pro Mini 3.3 V, a nRF24L01, and of course a big pushbutton on the top. Each one is powered by a 110 mAh 3.7 V LiPo battery, though [Flute Systems] notes that the current version of the buzzer can’t actually recharge it. You’ll need to pull the pack out and charge it manually once and awhile. Thankfully, the printed enclosure features a very clever twist-lock mechanism which makes it easy to open anytime you need to poke at the internals.

The base station uses the 5 V version of the Pro Mini, with a Adafruit PowerBoost 1000C to step up the voltage from its 2,000 mAh battery. Of course it also has a nRF24L01, and also adds a buzzer and twin four digit seven-segment LED displays. [Flute Systems] says you can expect about five hours of runtime for the base station.

An especially nice feature of this setup is that the eight digit display allows the base station to show the number of each button in the order it was received. So rather than just getting a display of who buzzed in first, you can see the chronological order in which all eight buttons were pressed. Coming up with clever applications for this capability is left as an exercise for the reader.

Of course, there’s more than one way to build a buzzer. If you don’t like the way [Flute Systems] did it, then check out this version that uses 900 MHz radios and an OLED to show the results.

In what we hope is a new trend in interviewing, some of the people at [Anthony]‘s place of work asked him to make some wireless quiz buttons. He took the task quite seriously, making them extremely robust and low-power.

[Anthony] is experienced in the button arts, having made this party push button for a wedding reception. His design for the quiz buttons is a little different. Each button has an Arduino Pro mini and an nRF24L01 wireless RF module. On the receiver side is an Arduino Pro micro and an another RF module. A connected PC captures the serial data and  displays the pressed button’s ID. It also shows the order in which subsequent buttons were pressed and the time elapsed between them.

The really notable part of this build aside from the awesome laser-cut MDF Devo energy dome button housings is the extremely low power consumption of the transmitting Arduinos. [Anthony] has designed them to go into sleep mode which disables all on-board circuitry and only wakes on interrupt. He removed the power LED and the voltage regulator since they run on 2-AA batteries. The voltage regulator was drawing more than 25mA in sleep mode. Because of these mods, each button consumes < 1μA, which is less power than the batteries can self discharge over their lifetime.

[Thanks Jef]

The four colored buttons seen above are a product made by Learning Resources. They flash and make noise when pressed and are meant for quiz-show style games in the classroom. The problem is that they don’t use a central controller, so it’s up to the person running the game to judge who rang in first. [Kenny] fixed that issue by building his own controller which is housed in that black project box.

He went with an Arduino Uno board. It fits in the project box and has no problem monitoring all of the buttons and triggering their sound and lights when necessary. There are two telephone jacks (RJ11 connectors) on either side of the controller. He also cracked open each button, cutting some traces on the PCB in order to patch the signals into connectors he added to the housing.

The video after the break shows the system in action, In addition to illuminating the first button to ring in there are LEDs on the box that indicate who was 2nd, 3rd, and 4th in line.

If you don’t want to purchase buttons try making your own with some cheap plastic bowls.