Wireless Hackerspace Status Notifier

May 23, 2011 by 5 Comments

space_probe

Hackerspaces are always looking for novel ways to let their members know that they are open for business, and this notifier [Angus] from Make, Hack, Void recently put together is no exception.

While dumpster diving one day, he came across a fantastic-looking lab power supply from the ‘70s. He gutted it, saving the variable transformer for a future project, and started constructing his notifier. When someone enters the hackerspace, they simply set the dial on the “Space Probe” to the amount of time they expect to be there. The built-in Seeduino sends the data over Bluetooth to an OpenWRT-enabled router, which uses a couple of Lua scripts to notify members via email and Twitter.

Since almost all of the processing is done on the router side, it leaves the Arduino in the probe with little more to do than flash an LED and send ASCII status messages any time the knob is turned. [Angus] is well aware that this would probably make most people’s heads spin, but he hopes that other hackerspace members use that untapped potential to further enhance the notifier.

Stick around to see the Space Probe in action, and if you are interested in seeing what other hackerspaces use to keep their members in the know, check out this status switch from Hack42.

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Dishwasher Notifier For The Absent-minded

April 12, 2011 by 28 Comments

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” on one side, “Dirty” on the other, but she chose the fun option and decided to over-engineer the problem instead.

She ultimately focused on two conditions that she needed to monitor: when the dishwasher had been run, and when the dishes have been emptied. To tackle the first condition, she used a thermistor to detect when the door of the dishwasher got hot from the wash cycle. The second wasn’t quite as easy, since she often peeks into the dishwasher to grab a clean dish when needed, unloading the rest later. She eventually settled on using a tilt switch to monitor the angle of the door, assuming that the dishes have been removed if the door was open for over a minute.

[Quinn] reports that her Dish-o-Tron 6000 works well, and she had a good time building it. Sure the whole thing is kind of overkill, but where’s the fun in moderation?

Public Transportation Notifier

April 12, 2010 by 29 Comments

[Knuckles904] was tired of waiting for the bus. His town had installed GPS units on the buses so that riders could track their locations via the Internet so he knew there should be a way to avoid the wait while also never missing the bus. He developed a sketch for an Arduino to check the bus location and notify him when it was on its way.

This method saves him from leaving his computer running. It parses the text data from the public transportation website and updates both an LED display, as well as a Twitter feed. Now he can monitor several different bus lines via the hardware at home, or though a cell phone if he’s on the go.

DIY AVR USB RGB LED Notifier

July 6, 2009 by 37 Comments

LED_notifier_in_place

Giving us a chance to break out the TLAs, [Blair] sent in his latest hack where he embedded an RGB LED into his EeePC to display twitter, pidgin, and email notifications. It is based around the ATtiny45, and requires very few additional parts. He based the project on a foundation of work laid by [Dennis Schulze] on notifications and the work of [Dave Hillier] that used V-USB, a library for implementing USB on AVRs. The entire circuit was done freehand and crammed inside the netbook. He says that it is a lot easier to see notifications, even when the laptop is shut.

Related: Email notification via RGB LED

Cellphone Ring Notifier

January 29, 2005 by 18 Comments

cell phone ring indicator

tom horsley got rid of his land line but didn’t want to lug his cell everywhere with him when he was in the house.  his solution was to hack together a light detection circuit, a wireless doorbell remote, and some paper mache into a giant incoming call noisemaker.  if you want to build your own, you should also check out version 2 that he is working on.

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Moving The Snail Mail To WiFi

June 7, 2023 by 22 Comments

[Zak] loves getting a notification on his phone when he gets physical mail. Enough to wire his mailbox slot with an ESP8285 to send him alerts. Previously, [Zak] used a cellular-based solution as the mailbox slot was not within WiFi range. However, the network provider for the A9G GPRS module decided to move to different towers, and suddenly the module didn’t work. Unable to find a provider that had sensible pricing, he got to work redesigning the module.

The mailbox was now in a WiFi network range, meaning he no longer had to use cellular. This dramatically simplifies the design and uses an ESP-M2 module (think ESP8266 but with embedded flash). To maximize battery life, the ESP is entirely off most of the time. A reed switch triggers a 74LVC1G98 NAND gate with an inverted input. This enables the 3.3 voltage regulator. A 4uF capacitor holds the voltage regulator on for 716ms, giving the ESP8266 time to boot and drive the second pin of the logic gate so it can stay on. Once the web request completes (a call to a PHP server that takes 4-5 seconds, including WiFi association), it pulls the pin low, and the system powers off. With a custom server, [Zak] can include a few goodies, such as temperature and humidity from the SHT32-DIS sensor.

So far, the system has been chugging along for seven months and over 110 mail notifications and has only dropped 0.3v, suggesting that the battery should hold out for another year or two before recharging. The code and schematics are up on GitHub. We love the low-power focus and the handy circuit explanation that makes it easy to use in other projects.

Fixing (And Improving!) An Annoying Apartment Entry System

December 11, 2022 by 7 Comments

[Zak]’s two-floor apartment has a typical door entry control system, but the setup is less than ideally convenient. The wall-mounted telephone-like intercom is downstairs, but [Zak] is usually upstairs. What’s an enterprising hacker to do? Obviously the most elegant solution is to simply do without visitors in the first place, but [Zak] opted for a more full-featured solution to the problem.

The layout of the typical wall-mounted door intercom is less than ideal.

He fixed things with a custom ESP8285-based board that, with the help of opto-isolation, allows him to detect visitors and grant entry without having to be physically present at the wall-mounted intercom. It’s even integrated into Telegram, and has a few neat new features. Let’s take a look.

The first interesting bit is how [Zak] rolled his own opto-isolation. The door entry system uses 14 VAC and is frankly — electromagnetically-speaking — a very noisy device. Attaching GPIO pins directly to this system from the ESP board for interfacing is not an option. The solution in situations like this is to use opto-isolation, so that interfaced devices can be electrically isolated from one another.

Rather than use off-the-shelf options, [Zak] opted to keep things small and economical by rolling his own solution using side-mounted IR LEDs on the small interface PCB. LEDs can also act as photodiodes, so by pointing two LEDs directly at one another and driving one LED from the door control system and measuring the small amount of resulting current on the other LED, [Zak] can detect states without having to directly connect a GPIO pin.

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