[Oneironaut] sent us another IR hack. This time it is a writeup on the best ways to create IR light sources from regular lights. Since normal flashlight bulbs emit a broad enough spectrum to include visible light and IR light, this basically comes down to filtering. [Oneironaut] explores different light sources and different materials in depth, along with great pictures to show his results. This is a great resource if you’re needing to do some night vision for cheap.
[Arthur Benemann] has the worst part of making coffee licked. His add-on for a drip coffee maker fills the water to the proper levels for you, saving the drudgery of rinsing out the carafe, carefully filling it to the appropriate level, then pouring it into the machine without getting everything wet. This isn’t limited to a full pot, but is user selectable by the cup based on how many times in a row you hit that red button. One LED gives feedback on the selected mode, then the device uses a washing machine water valve to turn on the tap for the appropriate amount of time. We’re a little bit leery of connecting homebrew hardware to the water pipes in our house. Make sure you’ve done a good job of debugging so that an infinite loop doesn’t flood you out.
Cats do what they want, which rarely coincides with what their owner wants them to do. In [Dumitru]’s case, his girlfriend’s cat [Pufu] tended to make it outside into the cold more often than desired. Rather than settle with the normal bell which gets obnoxious even when the cat isn’t misbehaving, he decided to put together a custom Cat Finding collar. He used a PIC microcontroller as the brains, and temperature and light sensors to decide whether the cat had snuck into the cold, dark night. Once the cat has been marked as being outside, a buzzer and LED are set to go off at regular intervals until returned into the safety of the indoors.
[Dumitru]’s website along with his YouTube videos are in Romanian, though the schematics and source code provided speak for themselves. He does a wonderful job walking through the entire design process, including time spend in the IDE as well as EAGLE designing the board. YouTube has managed to subtitle the majority of the details, but we imagine this post will be a real treat to any Romanian speaking hobbyists out there. Be sure to catch both videos after the break.
[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]
[Chr] picked up a pack of remote control outlets in order to reverse engineer them and build control into his own projects. These can be plugged into outlets around your house and a relay inside each module will switch whatever device is plugged into it after receiving a command from the remote. Once he cracked open the control housing it was easy to find the data line for the RF module which was on its own board. He used a logic analyzer to capture data from various button presses and then spent some time deciphering the communication protocol. He used what he learned to roll the module and code into an interface box where an ATmega8 connects via USB and passes commands from a computer to the RF board. Now he’s added home automation via a computer quite inexpensively. After the break you can watch a clip of the outlets switched using a smartphone.
So why not just patch into the buttons on the remote? Well, this same project was attempted at our local hackerspace earlier this month and the buttons don’t just pull a pin to ground. They use tri-state logic and are arranged into a matrix that is a lot harder to mimic (if not impossible) with a microcontroller. Analyzing the communications going into the RF module is definitely the less labor-intensive of the two approaches.
Continue reading “Reverse Engineering Radio Controlled Outlets”
[Mikey Sklar] wrote in to show us how he refurbished a neighbors useless refrigerator as a fermentation chamber. [Mikey] is a fan of making breads, kemchi, yogurt, and tempeh. To make these, it helps to have a completely controlled temperature for them to ferment in. [Mikey] developed a temp controller for this in the past, but had to either build a control box or use a giant chest freezer. This is not optimal for limited space, such as a kitchen. He got lucky when a neighbor tossed a wine cooler into the trash. These little coolers are perfectly sized for a kitchen and even have a glass front so you can keep an eye on what is going on inside without having to open it and effect your temps. [Mikey] ripped it open, replaced the peltier cooler with a large heat lamp and his temp controller. Since he was making yogurt with this one, he needed only to heat it. The final product turned out pretty effective.
[Billy’s] work got new keys which he didn’t want to carry around with him. Instead he built this system to unlock the door via text message. It is based around a Spinneret Web Server which drives a servo motor. He’s rigged up a pipe hanger to add some leverage to the lock’s knob. We’re surprised that the servo has enough power to do the job here but the video after the break shows there’s really no problem. On the communication side of things [Billy] set up Twilio to wait for text messages from an approved list of senders, then used an HTML form to issue the unlock commands to the webserver.
