Simple tweak alerts you when you've left your headlights on

April 11, 2012 By Leave a Comment

landrover-headlight-buzzer

[Paul McGuinness] owns a Series III Land Rover, and as the vehicle as formerly used by the British military, it’s lacking some of the modern amenities he was accustomed to. Overlooking the lack of power steering and all-around drum brakes, the one item that [Paul] really missed was a buzzer that let him know when he left the lights running.

On more than one occasion, he’s had to have “The Sarge” jump started after leaving the lights running all day. Explaining the humiliation involved with jump-starting a Land Rover with a Nissan Micra (an unfortunate excuse for a vehicle, known here in the states as the Nissan Versa) in his blog, [Paul] decided that he’d had enough – it was time to build a headlight warning buzzer.

The circuit itself is straightforward, consisting of a normally closed relay connected to his headlights and ignition, along with a buzzer. When the key is in the ignition and the lights are on, the relay is open and the buzzer is silent. However, if the lights are on and the relay is not supplied power from the ignition, it closes and sounds the alarm.

A simple fix for a frustrating problem – we like that.

Filed Under: transportation hacks Tagged With: , , ,

Preheat alarm added to a basic kitchen oven

March 7, 2012 By Leave a Comment

[Justin] didn’t want to keep checking if the ‘oven heating’ indicator light had gone off before popping his unbaked edibles into the oven. Many models offer a buzzer to let you know when the chosen temp is reached, but for folks who own a basic oven model there’s just a light that tells when the heating element is getting juice. Not to worry, he plied his circuit design skills and built a buzzer to alert him when the oven’s ready.

It only took a few components to accomplish the task. [Justin] uses a pair of NPN transistors triggered by a photoresistor. One transistor is responsible for switching on the buzzer, the other transistor is driven by the photoresistor and controls the base of its companion transistor (see the schematic for a better understanding).

He designed and etched a small PCB to host all the parts. As you can see above, it mounts over the indicator light and is powered by a 9V battery. There’s an on/off switch to the right so the buzzer doesn’t keep triggering while cooking, and a potentiometer allows him to fine-tune the photoresistor sensitivity.

Filed Under: cooking hacks Tagged With: , , , , ,

Office game show buzzer keeps things fair and square

February 3, 2012 By Leave a Comment

office-game-show-buzzer

The sales team in [Chuck’s] office is a pretty competitive bunch as you might expect, and they decided that they wanted a system which would allow them to challenge one another during their weekly meetings. The competition involves answering questions posed by their manager, but hand raising only works for so long – they needed a definitive way to tell who “buzzed in” to answer a question first.

Since [Chuck] only had a short bit of time and a tiny budget to work on, he opted to find the easiest solution to the problem, which was an Arduino-based game show buzzer system. The game display is built from an Arduino, some LEDs and an Altoids tin, while the buzzer pushbuttons were salvaged from an old radio broadcast console.

Now, when a question is posed, the salesman can buzz in to answer, knowing that only the quickest person’s button click will be registered. When it’s time for another question, the host simply clicks his buzzer to reset the console.

While it’s not quite as fancy as this game buzzer system we featured a while back, [Chuck] says it does the job perfectly and was cheap to boot.

Continue reading to see a short video of the office game buzzer system in action.

[Read more…]

Filed Under: arduino hacks Tagged With: , , , ,