ESP32 Adds New Features To 1990s Home Alarm System

November 2, 2020 by 16 Comments

Given how fast technology is progressing, some consumer gadgets lend themselves to being replaced every few years. Mobile phones are a particularly good example of a device that you probably won’t want to hold onto for more than 4 years or so, with TVs not far behind them. On the other hand, something like a home alarm system can stay in the fight for decades. As long as it still goes off when somebody tries to pop a window, what more do you need?

Well if you’re like [Brett Laniosh], you might want the ability to arm the system and check its current status from your phone. But instead of getting a whole new system, he decided to upgrade his circa 1993 Gardiner Gardtec 800 alarm with an ESP32. As it so happens, the original panel has an expansion connector which he was able to tap into without making any modifications to the alarm itself. If you’ve got a similar panel, you might even be able to use his source code and circuit schematics to perform your own modification.

Optocouplers link the ESP and alarm panel.

Now we know what you’re thinking. Surely there’s a risk involved when trusting an ESP32 connected to the Internet with the ability to disarm your home alarm system. [Brett] has considered this, and made sure that the web server running on the microcontroller can only be accessed from the local network. If he does want to connect from beyond WiFi range, he does so through a VPN. In other words, his code is never directly exposed to the wilds of the Internet and is always hiding behind some kind of encryption.

The WiFi connection allows [Brett] to arm and disarm the alarm system remotely, check if it’s been triggered, and reset it if necessary, all from his smartphone. But he’s also added in a 433 MHz receiver so he can use simple handheld fobs to arm the system if he doesn’t want to go through the phone. Even if you dropped out the Internet connectivity, this alone is a pretty nice upgrade.

For those not afraid to take the more invasive route, you could potentially reverse engineer and reprogram your old alarm panel. Or you could even so the full DIY route and create your own low-cost alarm system using the ESP32 and off-the-shelf modules.

Self Monitoring A Home Alarm System

September 18, 2012 by 16 Comments

[Lior] wanted to cancel the monitoring system for his home’s alarm, but he didn’t want to stop using the alarm all together. The trick is to rig up some way to monitor it himself. It would have been simple to have it just call him instead of the alarm company since the system just uses a telephone connection. But this would require that he have a land line for it to connect to, and when it calls him he would have no idea what part of the system had been set off. He developed a way to have the system text message him with all of the available details.

An Arduino controls the system, with a SIM900 GSM shield to hand the cell side of things. The board to the left emulates the standard telephone line, with an M8870 DTMF touch tone decoder to figure out what the alarm system is telling him. He also needed to implement touch tone generation to talk back to the system. His write-up includes links to other articles he posted about hardware, software, and protocol specifics.

Tweeting Home Alarm System

June 30, 2011 by 9 Comments

tweeting_home_alarm_system

Instructables user [willnue] wanted to build a DIY Tweeting alarm system from the ground up, but reconsidered after taking a close look at the scope of such a project. He settled on using an off the shelf security system, taking care of the Twitter interface on his own. He bought a GE 45142 Wireless alarm and promptly disassembled it to see how he might retrieve status messages from the unit.

He figured that monitoring the alarm’s LEDs would make the most sense, so he used a bit of Ethernet cable and wired all of the system’s indicators to his Arduino board. He hooked up an Ethernet shield to the Arduino, then wrapped the pair up in a plastic project box that closely matched the look of the security system. Once that was done, he wrote some simple code for the Arduino that monitors each of the alarm system’s six status lights, sending updates to Twitter via the ThingTweet service.

With this system you might not get your status messages in time to foil whoever is carrying off your plasma TV, but at least you will know what to expect once you get home!

If you want to keep tabs on [Will’s] security system to find out the best time to rob him see how things are going, check out his Twitter feed here.

Homemade Alarm System Doesn’t Lack Features

May 30, 2014 by 15 Comments

alarm system

To many of us, our garage (or workshop) is probably one of the most important parts of the house. If a burglar broke in, we’d likely be more worried about our tools! [Ron Czapala] decided he needed an alarm system in his garage to keep his stuff safe, so he decided to build one from scratch.

The system makes use of a Parallax 4×4 keypad membrane, a MCP23008 port expander, a Parallax Propeller, a LCD screen, and a few switches to represent future magnetic reed switches located in the door and window.

Using circular buffers, the propeller has several states for monitoring the garage.

  • Not armed — ignore all sensors
  • Armed — system will react to changes in the sensors
  • Exit delay — system has been armed, 45 second countdown has begun to allow you to exit the garage
  • Window trigger — if the window is opened, the alarm will go off immediately (siren and strobe light)
  • Door trigger — alarm will go off in 60 seconds if correct code has not been entered on the keypad

For a complete demonstration, check out the following video where [Ron] explains it all!

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Alarm Panel Hack Defeats Encryption By Ignoring It

January 19, 2024 by 23 Comments

As frustrating as it may be for a company to lock you into its ecosystem by encrypting their protocols, you have to admit that it presents an enticing challenge. Cracking encryption can be more trouble than it’s worth, though, especially when a device gives you all the tools you need to do an end-run around their encryption.

We’ll explain. For [Valdez], the encrypted communication protocols between a DSC alarm panel and the control pads on the system were serious impediments to integration into Home Assistant. While there are integrations available for these alarm panels, they rely on third-party clouds, which means that not only is your security system potentially telling another computer all your juicy details, but there’s also the very real possibility that the cloud system can either break or be shut down; remember the Chamberlain MyQ fiasco?

With these facts in mind, [Valdez] came up with a clever workaround to DSC encryption by focusing on physically interfacing with the keypad. The device has a common 16×2 LCD and a 25-key keypad, and a little poking around with a multimeter and a $20 logic analyzer eventually showed that the LCD had an HD44780 controller, and revealed all the lines needed to decode the display with an ESP32. Next up was interfacing with the keypad, which also involved a little multimeter work to determine that the keys were hooked up in a 5×5 matrix. Ten GPIOs on the ESP32 made it possible to virtually push any key; however, the ten relays [Valdez] originally used to do the switching proved unwieldy. That led to an optocoupler design, sadly not as clicky but certainly more compact and streamlined, and enabling complete control over the alarm system from Home Assistant.

We love this solution because, as [Valdez] aptly points out, the weakest point in any system is the place where it can’t be encrypted. Information has to flow between the user and the control panel, and by providing the electronic equivalents to eyes and fingers, the underlying encryption is moot. Hats off to [Valdez] for an excellent hack, and for sharing the wealth with the HA community.

Tiny Microcontroller Uses Real-Time Operating System

May 10, 2023 by 51 Comments

Most of the computers we interact with on a day-to-day basis use an operating system designed for flexibility. While these are great tools for getting work done or scrolling your favorite sites, they have a weakness when it comes to interacting quickly with a real-world environment. For these kinds of low-latency, high-reliability systems you may want to turn to something like freeRTOS which is optimized for this kind of application and which [Parikshit Pagare] has used to build his home automation system.

This build is based around an ESP32 for which freeRTOS, designed specifically for embedded systems, is uniquely suited. There are several channels built in capable of monitoring temperature, functioning as a smoke alarm, and sensing whether someone is at the front door. All of these are reported to a small OLED screen but are also updated on an Android app as well, which happens nearly instantaneously thanks to the real-time operating system. There are a number of user-controllable switches as well that are capable of turning lights or fans on and off.

For a home automation system, it’s one of the most low-cost and fully-featured we’ve seen and if you’re still having trouble coming across a Raspberry Pi as they sort out supply issues, something like this might make an excellent substitute at a fraction of the price. If you’re looking to expand even beyond this build, one of the gold standards for ESP32-based automation design is this build from [Marcus] which not only demonstrates how to build a system like this but goes into great detail on the ESPHome environment.

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Damaged Soyuz May Leave Crew Without A Ride Home

December 19, 2022 by 54 Comments

Though oddly beautiful in its own way, it’s a sight no astronaut wants to see: their spacecraft, the only way they have to return to Earth, ejecting countless iridescent droplets of something into space.

When the crew of Apollo 13 saw their craft literally bleeding out on their trip to the Moon it was clear the mission, and ultimately their lives, were in real jeopardy. Luckily the current situation is not nearly as dire, as the leaking Soyuz MS-22 spacecraft docked to the International Space Station doesn’t pose any immediate danger to those aboard the orbiting laboratory. But it’s still an unprecedented situation, and getting its crew home will require engineers on the ground to make some very difficult decisions.

This situation is still developing, and neither NASA nor their Russian counterpart Roscosmos have released much in the way of specifics. But we can make some educated guesses from the video and images we’ve seen of the stricken Soyuz capsule, and from what’s been shown to the public so far, things aren’t looking good.

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