Minimalistic 555 Adding Machine

How many 555 timers does it take to add up two 10 digit numbers? [Alan's] 555 Adding Machine does it with 102 of them, he designed the machine as an extreme entry to the 555 contest and the original plan was to make it even more complicated. This machine uses the 555′s to implement a nine decade accumulator and multiplexer, … Read the rest

Dishwasher notifier for the absent-minded

dish_o_tron_6000

[Quinn] over at BlondiHacks is admittedly pretty absent-minded when it comes to household chores such as emptying the dishwasher. She often can’t remember if the dishes are dirty or ready to be put away, so she decided it was time to devise a mechanism that would help keep her on task. She originally considered a double-sided sign that said “Clean” … Read the rest

Light-sensing circuit for power saving applications

light_sensing_circuit

Instructables user [MacDynamo] was thinking about home security systems and wondered how much electricity is being wasted while such systems are powered on, but not activated. He pondered it awhile, then designed a circuit that could be used to turn a security system on or off depending on the time of day, but without using any sort of clock.

His … Read the rest

Adjustable prank box growls and screams

growling_altoids_tin

[Brett] over at FightCube was tossing around ideas to build a screaming prank circuit that fits inside an Altoids tin. Sound familiar? We featured a story just a few days back about the construction of a very similar item by [Dino Segovis]. It seems that great minds think alike after all!

[Brett’s] version is a bit more robust than … Read the rest

Screaming Altoids tin just in time for April Fool’s

altoids_screamer

Maker [Dino Segovis] has started on a project he calls “Hack a week” where he will be putting together one hack or project per week, for a full year. The first installment of his video series was finished just two days before April Fool’s, and appropriately enough covers the construction of a circuit you can use to prank your friendsRead the rest

Real life Super Mario coin block

mario_coin_block

Instructables user [Bruno] recently constructed a fun little toy that brings a bit of the Mario nostalgia out of the video game universe and into ours. His Super Mario coin block is instantly recognizable from the first Mario game and performs just as you would expect it to. Punching or tapping the bottom of the block releases coins one at … Read the rest

Hardware-based security keypad keeps it simple

hardware_keypad_lock

Instructables user [trumpkin] recently built an all-hardware based keypad lock for a contest he was entering, and we thought it was pretty neat. The lock uses mostly NAND gates and 555 timers to get the job done, which makes it a nice alternative to similar software-based projects we have seen in the past.

The lock has 6 keys on the … Read the rest