Scratch-built railroad crossing signal

At first glance you would think this is the real thing, but [Kevin] built this railroad crossing signal from parts you can find at the home store. We keep seeing traffic lights used as web-connected signaling devices. This would be right at home for that type of setup, but [Kevin] built it with railroad enthusiasts in mind.

He used Google SketchUp to design the frame for the signal, then purchased all of the PVC parts to match those specifications. Some grey spray paint goes a long way to making it look like steel tubing. But this is much easier to work with and he should have no trouble internalizing the wiring later on. The lights themselves are tail lights for a trailer with a decorative trim piece added. He designed his own driver board to switch the lights and ring the doorbell which give the signal some sound. His first version used a 555 timer, this one upgrades to microcontroller. We like what he’s doing in the video after the break, but think the bell speed needs to be doubled for it to mimick the real thing just about perfectly.

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A doorbell pleasing to both the ears and eyes

campanello-doorbell

When [David] moved into his new house, one of the things he noticed was that his doorbell was pretty lame. Coming from a home equipped with a solenoid and chime bell, his new wireless solid state doorbell sounded terrible to him.

Crummy sound aside, the doorbell hardly ever worked properly, but alas, other projects cropped up and years went by before [David] addressed his doorbell problem. Like many things that take a long time to come to fruition, we think his resonator bell based solution was well worth the wait.

One of his main goals was to make a nice sounding doorbell that also looked great. He mounted a kid’s resonator bell toy on a sheet of wood, creating his own wooden mallets for the job. He initially had a tough time locating actuators for his doorbell, but found a solution in geared pager motors as featured in another xylophone hack on Make. With the hardware taken care of he focused on the electronics, which consist of a pair of Arduino clones – one on the display and one in his basement.

Stick around to see [David’s] Campanello doorbell in action, and be sure to check out his site for more details if this sounds like something you would like to have in your home.

[via Make]

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A doorbell loud enough to wake the dead

really_loud_doorbell

[Ed Nauman] runs a machine shop, which we imagine can be quite loud at times. Sick of never hearing the doorbell when he was busy working on things, he decided that the solution to his problem was a new doorbell…an incredibly loud doorbell.

His Really Loud Doorbell (RLD for short) is actually a pretty simple device. We imagine he could have wired up an old alarm bell instead, but where’s the fun in that? The doorbell was built using a PIC16F876 uC, which is used to control the air flow through a pneumatic valve. When someone rings his doorbell, the pneumatic actuator pulses up and down, rapidly striking a piece of 1/4” thick steel pipe. As you can see in the video below, it is quite loud and likely to cut through any shop noise without much trouble.

We have seen some extremely loud doorbells before, but we figured that at least a handful of you work in similar environments – have you implemented any inventive ‘notification’ systems in your workspace? Let us know in the comments.

[via Adafruit Blog]

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Doorbell hack makes coworkers less annoying

doorbell_wav_player

Hackaday reader [Sprite_tm] works in an office building that used to house several businesses, and as a remnant of the previous configuration, a doorbell sits in the hallway just outside his office. Several of his coworkers get a kick out of ringing the doorbell each time they enter the office. While not annoyed at the practice, he was getting tired of the same old “ding-dong” and decided to shake things up a bit.

He wanted to modify the doorbell to play random sounds when triggered, but he was pressed for time as it was March 31st, and he wanted to get it installed for April Fools’ Day. Without any real plan or bill of materials in mind, he pieced things together with whatever he happened to have sitting around.

He used a design borrowed from Elm-chan in order to play wav files from an SD card with an ATTiny85, and used an L293 H-Driver as an improvised sound amplifier. After sorting out some power-related problems, and configuring the circuit to be as stingy with its battery as he could, he declared the project complete. He originally aimed to deadbug everything on the metal sleeve of the SD card socket (which is awesome), but considering the size of the speaker and the battery he selected for the project, he ended up stuffing everything into a cardboard box.

We don’t care too much about how he packaged it, we just wanted to know what his co-workers thought of his doorbell augmentation. In the end, they loved it, but we imagine this doesn’t do anything to discourage any of them from hitting the doorbell multiple times a day.

Stick around to see a quick video of his doorbell hack in action.

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Growling doorbell lets you know guests have arrived

wireless_doorbell_hack

[Sean] was screwing around online looking for nothing in particular when he came across a mailbox hacked to notify the homeowner when the mail had been delivered. Since his mail is delivered via a slot in the door, he had no use for the hack as is, but something similar soon came to mind.

His dog isn’t too keen on visitors, and he figured that he could save himself a bit of grief (and a lot of unnecessary barking) if he were to wire up his doorbell to notify him of guests via his iPhone. He stopped by the local hardware store and picked up a wireless doorbell. It was quickly disassembled and wired up to an Arduino he had set aside for a different project. Tweaking some code he found online, he soon had the doorbell talking with the Arduino and was ready to interface it with his iPhone. He decided that he wanted to deliver notifications to his phone via Growl and found a Perl script online that was close to what he needed. A few tweaks later, and he had a Growling doorbell.

As you can see in the video below, it works, though there seems to be a bit of a delay in the notification. We don’t think that it would be enough to send his visitors packing before he made it to the door, but the lag can likely be reduced with a few small modifications.

As for the post that started this whole thing, we’re pretty sure this is it.

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Snail mail notification system

[Mime] lives on one of the upper levels of an apartment complex. The mailboxes, being located at the ground floor can be somewhat inconvenient to check regularly. [Mime] decided to rig up a device to let him know when his mailbox had been accessed. He started with a wireless doorbell, thinking he could use the door side button inside his mailbox as a trigger with only some slight modification. On the receiver side, he wanted an LED to flash, letting him know that it was time to check his mail. One simple circuit and a self blinking LED later and the whole setup was finished. Great job [Mime]

Replacing the driver board in an old-school door chime

[Dan Kouba’s] parents replaced their doorbell button with one that lights up and found that the chime wouldn’t stop sounding after the button was pushed. These lighted buttons use an incandescent bulb in parallel with the button (a piece of hardware we’ve hacked in the past). It draws a small amount of current which isn’t enough to trigger the chime, but it is just enough that the chime unit reacts as if the button press never stopped. His parents asked what he could do about this and after some investigation he build a replacement board for the chime unit based around an ATtiny26L. The board monitors the voltage drop across a resistor in the doorbell circuit. When the comparator on the AVR detects a rise in the voltage drop across the resistor it rings the chimes, actuating the solenoids with a set of PNP transistors. [Dan] sent us all of the details which you can check out after the break.

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