When designing an RFID access control system, one has to decide what kind of reader and what kind of tags one wishes to use. They all function more or less the same way, but there are a lot of practical considerations to take into account such as cost, range, ease of use, and security options. After a lot of research, [Glen] decided on inexpensive sticker-style tags and a compatible reader supporting credentials with an ISO14443 UID that could be suitably mounted on a building’s exterior.
Breakout boards with ready-to-use code libraries exist for some RFID readers, but that wasn’t the case for the reader [Glen] had. He ended up rolling his own code to handle communication with the reader, with a Microchip PIC18F45K50 doing all the work of reading tags and performing access control. His code is on the project’s GitHub repository, and if you also find yourself needing to interface to a reader that uses the Wiegand protocol, you might want to give it a look.
Controlling the actual garage door was the easy part. All that took was soldering two wires across the switch contacts of a spare garage door opener remote, and using a relay to close the contacts. Simple and effective. You can see it in action in the short video, embedded below the break.
For devices that are destined for momentary and infrequent use as well as battery power, some kind of power saving is pretty much a required feature. For example, when [PJ Allen] turned two ESP8266-based NodeMCU development boards into a replacement wireless remote garage door opener, a handy USB power bank ended up serving as a bit of a cheat when migrating the remote away from the workbench. Instead of moving the board from USB to battery power and implementing some kind of sleep mode or auto-off, [PJ Allen] simply plugged in a USB power bank and let it do all the work.
This is how the feature works: some USB power banks turn themselves off unless they detect a meaningful current draw. That means that if the power bank is charging a phone, it stays on, but if it’s only lighting up a few LEDs, it’ll turn itself off. This feature can be a frustrating one, but [PJ Allen] realized that it could actually be useful for a device like his garage door remote. Turning on the power bank delivers 5 V to the NodeMCU board and allows it to work, but after about fifteen seconds, the power bank turns itself off. Sure, strapping a power bank to the remote makes the whole thing bigger than it needs to be, but it’s a pretty clever use of the minimum load as an effortless auto-off feature.
The NodeMCU boards in [PJ Allen]’s DIY remote use ESP-NOW for their wireless communications, a nifty connectionless protocol from Espressif that we’ve seen used in other projects as well, such as this ESP32-based walkie-talkie.
It’s getting into the hot summer months for those of us in the Northern Hemisphere, and for many Hackaday readers, that means its time to get the old window air conditioner out of storage and lug it back into position. But what if you’re trying to cool a space that doesn’t have a convenient window? In that case, this clever conversion that [Infrared] came up with to keep his garage cool might be of interest.
Basically, he’s taken the classic window AC and turned it into an impromptu ductless unit. By rotating the evaporator coils into a vertical position and lengthening the compressor wires, he was able to make the center of the AC thin enough that he could close his garage door over it. The back of the unit looks largely untouched, but the front side has a real Mad Max vibe going on; with sheet metal, exposed wiring, and a couple of fans thrown in for good measure. Fine for the garage or workspace, but probably not a great choice for the kid’s room.
The ESP8266 is a great processor for a lot of projects needing a small microcontroller and Wi-Fi, all for a reasonable price and in some pretty small form factors. [Simon] used one to build a garage door opener. This project isn’t really about his garage door opener based on a cheap WiFi-enabled chip, though. It’s about the four year process he went through to learn how to develop on these chips, and luckily he wrote a guide that anyone can use so that we don’t make the same mistakes he did.
The guide starts by suggesting which specific products are the easiest to use, and then moves on to some “best practices” for using these devices (with which we can’t argue much), before going through some example code. The most valuable parts of this guide especially for anyone starting out with these chips are the section which details how to get the web server up and running, and the best practices for developing HTML code for the tiny device (hint: develop somewhere else).
[Simon] also makes extensive use of the Chrome developers tools when building the HTML for the ESP. This is a handy trick even outside of ESP8266 development which might be useful for other tasks as well. Even though most of the guide won’t be new to anyone with experience with these boards, there are a few gems within it like this one that might help in other unrelated projects. It’s a good read and goes into a lot of detail about more than just the ESP chips. If you just want to open your garage door, though, you have lots of options.
Garage doors can be frustrating things, being a chore to open manually and all. Many people opt to install a motorized opener, but for some, even this isn’t enough. Hooking up a garage door to the Internet of Things has long been a popular project, and [Simon Ludborzs] decided to give it a shot. Naturally, there were some obstacles to be overcome along the way.
[Simon]’s build is relatively straight down the lines, using an ESP-12 as the brains of the operation, which connects to the internet over WiFi. However, robustness was a major goal of the project, and being reliant on shaky cloud-based services wouldn’t do. This opener is set up to work independently of an internet connection, too. There’s a nifty control panel with glowing buttons to operate the opener, in addition to the webpage served up on the network.
Today’s story is one of victory and defeat, of mystery and adventure… It’s time to automate the garage door. Connecting the garage door to the internet was a must on my list of smart home features. Our opener has internet connection capabilities built-in. As you might guess, I’m very skeptical of connecting a device to the internet when I have no control over the software running on it.
The garage door is controlled by a button hung on the garage wall. There is only a pair of wires, so a simple relay should be all that is needed to simulate the button press from a Raspberry Pi. I wired a relay module to a GPIO on the Pi mounted in the garage ceiling, and wrote a quick and dirty test program in Python. Sure enough, the little relay was clicking happily– but the garage door wasn’t budging. Time to troubleshoot. Does the push button still work? *raises the garage door* yep. How about the relay now? *click…click* nope.
You may have figured out by now, but this garage door opener isn’t just a simple momentary contact push button. Yes, that’s a microcontroller, in a garage door button. This sort of scenario calls for forensic equipment more capable than a simple multimeter, and so I turned to Amazon for a USB oscilloscope that could do some limited signal analysis. A device with Linux support was a must, and Pico Technology fit the bill nicely.
Searching for a Secret We Don’t Actually Need
My 2 channel Picotech oscilloscope, the 2204A, finally arrived, and it was time to see what sort of alien technology was in this garage door opener. There are two leads to the button, a ground and a five volt line. When the button is pressed, the microcontroller sends data back over that line by pulling the 5 V line to ground. If this isn’t an implementation of Dallas 1-wire, it’s a very similar concept.
Car lifts used to be a tool reserved for professional mechanics. Times are a-changing though. With the advent of reasonably priced four-post hydraulic lifts, more and more shade tree mechanics are joining the five-foot high club. Installing a lift in a home garage creates a few hazards, though. What happens when a family remotely opens the garage door while there is a car up on the lift? Garage door and lifted vehicle will meet – with expensive and/or dangerous results. [Joe Auman] saw this problem coming a mile away. He built the LiftLocker to make sure it never happens to him.
At its core, LiftLocker is a set of switched extension cords. Two cast-aluminum boxes hide the electronics. One box plugs in-line with the lift. The other box plugs in-line with the garage door opener. Each box includes a Sparkfun Redboard Arduino compatible, an RFM22 433 MHz Radio, and a relay. Input comes from a security system magnetic reed-switch. Both boxes are identical in hardware and code.
Operation is simple. One box and reed switch goes on the lift, the other on the garage door. If the lift is going up, its reed switch will open. The lift’s Arduino detects this and commands its RFM22 to send a signal to the other box on the garage door. Upon receiving this signal, the garage door controller will open its relay, disconnecting power to the garage door opener. Communication is two-way, so if the Lift controller doesn’t hear an ACK message from the garage door controller, everything will shut down. Click past the break to see the system in action.