Here’s a little smoke detector hack which [Ivan] has been working on. He wanted to extend the functionality of a standard detector and we’re happy to see that he’s doing it with as little alteration to the original equipment as possible (this is a life-saving device after all). He sent all the build images for the project to our tips line. You’ll find the assembly photos and schematic in the gallery after the break.
As you can see his entry point is the piezo element which generates the shrill sound when smoke as been detected. He connected this to his own hardware using an optoisolator. This allows him to monitor the state of the smoke alarm on his server. It then takes over, providing a webpage that display’s the board’s temperature sensor value and streams video from an infrared camera.
Of course this is of limited value. We’ve always made sure that our home was equipped with smoke detectors but the only time they’ve ever gone off was from normal cooking smoke or after an extremely steamy shower. But still, it’s a fun project to learn from and we’ve actually got several of the older 9V battery type of detectors sitting in our junk bin.
Continue reading “Beefing up a smoke alarm system with video, temperature, and connectivity”
As part of a complete home theater setup [Andy] wanted to be able to control the lights from his couch. He started thinking about the best way to do this when he realized that his TV remote has buttons on it which he never uses. Those controls are meant for other components made by the same manufacturer as the TV. Since he doesn’t have that equipment on hand, he built his own IR receiver to switch the lights with those unused buttons.
He monitors and IR receiver using an AVR microcontroller. It is powered from mains via the guts from a wall wart included in the build. Also rolled into the project is a solid state relay capable of switching the mains feed to the light circuit. [Andy] mentions that going with a solid state part mean you don’t get that clicking associated with a mechanical relay. An electrical box extension was used to give him more room for mounting the IR receiver and housing his DIY circuit board.
It figures. You spend a ton of time making a cool set of costumes and then you can’t get your kid to pose for a picture. It’s okay though, we still get the point. This themed set of costumes dresses the little one as a Roomba vacuuming robot while mom and dad are suited up as virtual walls (modules that are used to keep the bot from falling down stairs, etc.). It’s fun and unique, but had it not been for some additional electronics this would have been relegated to a links post. For safety sake each costume was outfitted with a ring of LEDs. As a challenge, the lights were given the ability to sync up patterns with each other.
Each costume has a circular frame at the top with a set of RGB LED strings attached. To get them to display synchronized patterns an IR transmitter/receiver board was designed and ordered from OSHPark. Each costume has four of these modules so no matter where the wearers are facing it should not break communications. A demo of the synchronized light rings can be seen after the break
Continue reading “Roomba and virtual walls make up this theme family Halloween costume”
Just the other day we were reading a Reddit thread asking about how to control a television with a smartphone. The conversation started by talking about adding an IR LED to the phone. Then it was suggested that there should be standalone Bluetooth devices that convert commands to IR, and came around to the ideas that TV’s should ship with native Bluetooth hardware. We couldn’t agree more but we’re also not about to replace our TV just for this option. That’s why we were delighted to find this project waiting on our tip line. It’s a method of controlling a camera shutter from a smartphone using Bluetooth. But the technique will work for any device which uses an infrared remote control.
The video after the break shows two different devices controlling the camera shutter. As you can see in the diagram above, the iPhone is the master controller, connecting to a Bluetooth headset mounted on the camera. That headset was altered to feed the speaker connections into an IR LED pointed at the camera’s receiver. The iPhone plays an encoded audio track matching the IR remote command, resulting in the properly formatted message flashing on the LED. The watch doesn’t have the ability to playback audio, but it can send a message to the phone, which then plays the proper audio track through the headset.
Continue reading “Bluetooth control for your DSLR or just about any other IR operated device”
This home automation hardware turns on and off the lights based on room occupancy. The hack is an extension of an earlier version that was only a proof of concept. [RPisces] took the idea and made it into reality by mounting the sensor hardware in a doorway.
He prototyped the device using the MSP430 launchpad. It monitors a pair of IR distance sensors which record a change when something passes between them and the opposite side of the hallway. This is a good sensor choice as it only requires hardware on one side of the passageway. Because two of them are used, it’s quite simple to figure out if a person is entering or leaving the room based on which is tripped first.
In this case [RPisces] drives a relay to switch a lamp on and off. But it could be used for just about anything. We’d enjoy seeing it trigger an audio system like the one [Quinn’s] installing in every room.
This device is a prank or gag that [Eric Heisler] came up with. It will intercept IR remote control codes and play them back after a bit of a delay. The example he shows in the video (embedded after the break) catches the television power signal from a remote, then sends it again after about thirty seconds. This shuts off the TV and would be extremely annoying if you were unable to find the device. Fortunately (for the victim), [Eric] included a piezo buzzer that Rickrolls after sending each code. Just follow that tune to find the offending hardware.
He chose to use an ATtiny10 microcontroller. It looks like it’s realizing its full potential as the six-pin package use all available I/O to control the IR receiver module, an IR led, and the buzzer. It runs from a coin cell without regulation and the circuit was free-formed on a tiny surface mount breakout board which hosts the microprocessor.
This tutorial will guide you through the process of building a tachometer around an Arduino. Tachometers are used to measure rotation rate in Revolutions Per Minute (RPM). You don’t need much in the way of hardware, this version uses an Infrared beam to measure fan speed. As with last year’s PIC-based tutorial, [Chris] is using a character LCD to output the reading. Wiring and driving the LCD ends up being the hardest part.
An IR transmitter/receiver pair are positioned on either side of the fan. When the blade passes in between then, the receiver shuts off a transistor connected to one of the Arduino’s external interrupt pins. He shows how to use this interrupt to measure the amount of time between the passing of each fan blade. If you divide for the number of blades, and average the reading for greater accuracy, you can easily calculate RPM.
Another alternative would have been to use a reflectance sensor which allows to for the transmitter and receiver to both be on the same side of the fan.