Hello Everyone!

This instructable explains how I setup a Raspberry Pi to open my garage door using a smarthphone. While this has been done before, I thought I'd post my solution. This was my first hardware project and instructable ever and I'm sure I made some mistakes. So, when you find one let me know! 

Project Overview:
What we will be doing is turning the Raspberry Pi into a small web server. When you access the webserver from your browser of choice, you will have a big button that triggers the garage door via a relay. We will wire a very basic circuit to the Pi's GPIO pins and upload a website that triggers the circuit. When the relay is triggered, it closes the circuit hooked up to the garage motor and opens the garage.

Why would anyone want to do this?
Well, my garage door opener was broke and this was cheaper than replacing the other system. As an added plus though, you could wire up additional sensors and be able to make sure your garage is closed remotely if your were so inclined.

Shopping List:
I consider myself pretty cheap, and I tried to keep the costs minimal. All of the items are available on prime.

1.) Raspberry Pi - Model A - $32

2.) Wifi Adapter - $10

3.) PSU - $5

4.) 5v Relay - $6

Total: $53.00

You will also need an sdcard >= 2GB and some wires, but I had extra of each.

Step 1: Install and Optimize Rasbian (for Our Purposes)

This first step is to install an operating system to your rpi. I'm a bit of a debian fanboy, and had an extra 2GB sdcard, so I went with a shrunk version of Wheezy. The image I used can be found here:


For full instructions on installing an OS to your PI and other images, visit http://www.raspberrypi.org/downloads.

On Ubuntu, I used gparted to format to fat32, and dd to write the img.

After you install the OS, plug in a usb keyboard and hook up the raspberry pi to a monitor. Assuming you are using Wheezy, on the first boot rasp-config will automatically run. You should use this tool to stretch the parition and enable ssh (under the advanced menu on newer versions I believe).

After I installed my img, I also removed the GUI to free up some space. (If you have a large SD, you can skip this.) To do this type these commands:

$ sudo apt-get remove --purge x11-common
$ sudo apt-get autoremove

This removes all packages that depend on X11 which is pretty much all of the GUI.

Step 2: Setup Wifi Via the Command Line

The next step is to setup your wifi from the command line. This will allow us to control the pi remotely via ssh.

Here is a great guide for Wheezy:

Since we are using the Model A with only one usb port, you will need to set up the configuration with your keyboard, shutdown the pi, insert the Wifi Dongle and then start it backup. This may take a little guess and check.

The command to shutdown the pi is: sudo shutdown -h 0

If all goes well, once you set it up and reboot, your pi will be given an IP address by your router. You can find this IP address by either hooking the pi up to an hdmi monitor and looking at the boot log, or logging in to your router and looking at the DHCP table.

Step 3: Install Software

Now that we have the wifi setup, we are going to download and install the necessary software to our pi. Since our usb port is now being used by the wifi dongle, we will do this via ssh.

If you are using Ubuntu, open up the terminal and type ssh pi@[Your Pi's Ip address]. If you are using Windows, you can download Putty. On OSX, you can also just ssh from the terminal. Again, the default password on Wheezy is raspberry.

Once your a logged in, download, compile, and install Wiring Pi. This software allows us to control the GPIO pins on the pi. Here is a step by step guide for that:

Once Wiring Pi is installed, you will want to install Apache and PHP via these commands:

$ sudo apt-get update
$ sudo apt-get install apache2 php5 libapache2-mod-php5

Once this is done, you will have a working webserver! To verify that, just type in your pi's ip adress in a browser. You should see Apache's default website which says "It Works!".

Step 4: Upload the Garage Opener Website

Now that we have a working webserver, we are going to upload a website to it. I've created a very basic one that will trigger the relay we will wire in the next step.

Here are two ways to do that:

Dowload the GarageOpener.zip to your desktop. Open up your terminal, and type the following commands:
$ sudo rm /var/www/index.html
$ sudo chown pi:root /var/www
$ exit
$ cd ~/Desktop
$ scp GarageOpener.zip pi@[YOUR PI'S IP ADDRESS]:/var/www
$ cd /var/www
$ unzip GarageOpener.zip
$ rm GarageOpener.zip

Any OS
Download Filezilla. Using Putty or another ssh terminal:
$ sudo chown -R pi:root /var/www

Start filezilla. Log into the raspberry pi with these credentials:
Host: sftp://[YOUR PI'S IP ADDRESS]
Username: pi
Password: raspberry

Then upload all of the files from GarageOpener.zip to /var/www. Also, delete the existing index.html.

Some Technical Notes (for those interested):
The website uses jQuery to post to itself (via AJAX) when a user clicks on the big button. I did this so that if you refresh the page it doesn't trigger your garage to open.

If your using an iPhone (or the latest dev version of Chrome on Android) and add this website to your home screen, it should work like an app without the browser chrome. (It will still only work when your on your home wifi though :-P )

Step 5: Wire the Circuit to the Pi!

Now for the fun part - we wire the relay to the pi! For the code I provided (step 4 and 6) I used GPIO pin 7. You can use whichever one you want, but be sure to change the code.

Below is a diagram and my wired pi mounted on cardboard with zip ties. I used an old floppy disk ribbon cable for easy testing of ports and just left it connected.

Step 6: Create a Startup Service

This step is important.
Most relays including the one I purchased, operate like this - when the signal is ON the circuit stays off. When the signal is OFF then the circuit is on. So what happens if your pi looses power? Well most relays have a safety mechanism that keeps the circuit OFF when there is no power at all. The problem that occurs happens between when the pi (and subsequently the relay) gets its power back but before the pi has finished booting to turn the signal ON which is need to keep the circuit off. You could wake up in the morning with your garage open and potentially a few new friends!

After some experimenting, I found a simply work around. I found out that my relay doesn't actually initialize until the GPIO pin mode is set via this command: gpio mode 7 out. Furthermore, I found out that it you set the GPIO pin to ON (gpio write 7 1)before you set the GPIO mode, the relay will stay off once initialized.

To make this initialization run at boot, I created a start-up script.

$ ssh pi@[Your Pi's IP]
$ sudo nano /etc/init.d/garagerelay

Then paste this script:
#! /bin/bash
# /etc/init.d/garagerelay

# Carry out specific functions when asked to by the system
case "$1" in
echo "Starting Relay"
# Turn 7 on which keeps relay off
/usr/local/bin/gpio write 7 1
#Start Gpio
/usr/local/bin/gpio mode 7 out
echo "Stopping gpio"
echo "Usage: /etc/init.d/garagerelay {start|stop}"
exit 1

exit 0

Make the file executable:
$ sudo chmod 777 /etc/init.d/garagerelay

Now tell your pi to run this script at boot:
$ sudo update-rc.d -f garagerelay start 4
(Note: You can safely ignore the "missing LSB tags" warning.)


Step 7: Attach Raspberry Pi to the Garage

This part is very easy. Just follow the wires of the button attached to your garage motor and attach the relay the same way. Since the relay isolates the circuit, the direction doesn't even matter.

And you're done! Let me know it works for you.
<p>This worked great to get me started but like others I did have to tweak the code for two reasons:</p><p> 1. My relay was closed by default so I had to reverse the scripts to leave to circuit open</p><p> 2. I didn't have a full ribbon cable so I used GPIO 1 (pin 12) instead of 7.</p><p>Here are my resulting files in case they can help someone else get started</p><p>/var/www/html/index.php (note the corrected location):</p><p> &lt;?php<br> if(isset($_GET['trigger']) &amp;&amp; $_GET['trigger'] == 1) {<br> error_reporting(E_ALL);<br> exec('gpio write 1 1');<br> usleep(1000000);<br> exec('gpio write 1 0');<br> }<br> ?&gt;<br> &lt;!DOCTYPE html&gt;<br> &lt;html&gt;<br> &lt;head&gt;<br> &lt;title&gt;Garage Opener&lt;/title&gt;<br> &lt;link rel=&quot;apple-touch-icon&quot; href=&quot;apple-touch-icon-iphone.png&quot; /&gt;&lt;link rel=&quot;apple-touch-icon&quot; sizes=&quot;72x72&quot; href=&quot;apple-touch-icon-ipad.png&quot; /&gt;<br> &lt;link rel=&quot;apple-touch-icon&quot; sizes=&quot;114x114&quot; href=&quot;apple-touch-icon-iphone-retina-display.png&quot; /&gt;<br> &lt;link rel=&quot;stylesheet&quot; href=&quot;/css/style.css&quot; type=&quot;text/css&quot;&gt;<br> &lt;meta name=&quot;apple-mobile-web-app-capable&quot; content=&quot;yes&quot;&gt;<br> &lt;script type=&quot;text/javascript&quot; src=&quot;/js/jquery-1.10.2.min.js&quot;&gt;&lt;/script&gt;<br> &lt;script type=&quot;text/javascript&quot; src=&quot;/js/script.js&quot;&gt;&lt;/script&gt;<br> &lt;/head&gt;<br> &lt;body&gt;<br> &lt;div class='awrap'&gt;<br> &lt;a href='/?trigger=1'&gt;&lt;/a&gt;<br> &lt;/div&gt;<br> &lt;/body&gt;<br> &lt;/html&gt;</p><p>/etc/init.d/garagerelay:</p><p> #! /bin/bash<br> # /etc/init.d/garagerelay<br> # Carry out specific functions when asked to by the system<br> case &quot;$1&quot; in<br> start)<br> echo &quot;Starting Relay&quot;<br> # Turn 1 on which keeps relay off<br> /usr/local/bin/gpio write 1 0<br> #Start Gpio<br> /usr/local/bin/gpio mode 1 output<br> ;;<br> stop)<br> echo &quot;Stopping gpio&quot;<br> ;;<br> *)<br> echo &quot;Usage: /etc/init.d/garagerelay {start|stop}&quot;<br> exit 1<br> ;;<br> esac<br> exit 0</p>
<p>https://github.com/amorales2/GarageDoorProject</p><p>I modified the code so that hitting the page is all it takes to open the garage door. Then I created a task with the tasker app that lets me open the door with my phone, and also have a nice button on the home screen :)</p>
<p>I checked my Pi's IP address after doing the apache part like mentioned and I saw the &quot;It Works&quot; screen. Before I brought it out and hooked up to my garage door I went to check again and am getting a Not Found error. Any ideas how to fix this?</p>
<p>To update a little, I went on my laptop command prompt and did a ping 192.168.1.xxx and am not getting any packet loss at all so it can see that I am connected to the same wifi, but still get the 404 Not Found</p><p>I have not connected it to my garage door yet, but I am assuming that would not be the cause. I suppose I could connect it to test this theory out though.</p>
<p>I have a reply above about this in more detail but basically you want to check your apache error logs: </p><p>sudo tail /var/log/apache2/error.log</p><p>And it will tell you where it is looking for your site. Make sure that your site index.php file is in the folder that the error log lists as the location that was not found.</p>
<p>Ok, I'm farther down the path now. I've got a Rasbian jessie image changing the value of pin 7. It seems apache by default makes it's web root in /var/www/html</p><p>Place your files such that the index.php files is in that folder and you should make some headway.</p>
<p>Hi all. Didn't work for me. After I copied the files and opened the website all I got was a 404 Not Found msg. Can someone help out?</p>
<p>I haven't tried this project yet but I am a<br> full stack web developer. You should be able to find error logs for <br>apache (your web server). By default they will be located in:</p><p>/var/log/apache2/error.log</p><p>You can look at the most recent errors with a text editor with something like:</p><p>sudo tail /var/log/apache2/error.log</p><p>Chances<br> are that it is looking in the wrong folder for your site as it is <br>saying that it can't find the files (404). The error log should have <br>some advice on what folder it is currently looking in. Once you know <br>where it is looking, move your stuff there (make sure that your index file is in the folder it is looking in) and it should either <br>find the site or give you a new error to work through :)</p>
<p>I have a problem. when I type in: sudo chown -R pi:root /var/www into the ssh, nothing happens. no folder is created or anything :( plz help</p>
<p>Did you ever solve this, i am having the same issue</p>
<p>chown changes the ownership of a file or folder. In this case the command you are issuing is basically saying, change the /var/www folder (if it exists) and everything in it to be owned by the pi user and root group. If you don't have a /var/www folder, you can make it first by issuing:</p><p>mkdir -p /var/www</p><p>(make the /var/www directory and also make it's parent if they don't exist) if it complains about permissions put a sudo in front of it.</p><p>Once you have the folder, you can issue your chown command again and then you can check the results of your command by issuing:</p><p>cd /var</p><p>ls -l</p><p>Which translates to &quot;move to the /var directory then list in long format the contents of that directory&quot;. You should see the files in and folders in the /var directory with the group and owner listed beside each item. You are hoping for the line for www to look something like this:</p><p>drwxr-xr-x 3 pi root 4096 Jan 28 2016 www</p>
<p>Finally got it working :-) but had to make a few modifications. I used Raspbian Jesse and WiringPi for gpio control was already installed but was located at /usr/bin/gpio instead of /usr/local/bin/gpio so I had to modify my garagerelay file to match. I am not sure if the same thing caused my other issue but if I entered the gpio commands manually at the bash prompt it would trigger the door but the webpage button would not. I ended up making a shell script file called door.sh and making it executable and then removed the exec gpio and usleep commands and replacing it with exec(&quot;/home/pi/door.sh&quot;); and that worked. </p>
<p>This may be a stupid question to ask here. I am a newbie in IoT Home Automation area. However I do have a lot of technical background, so I hope that I will be able to understand your technical jargons :)</p><p>My question is - does this solution work for garage door that's canopy up and over? If yes - can a single integrated system be used to manage both doors, but can be controlled in user's discretion (i.e one door at a time or both at a time).</p><p>Any feedback or mentoring is really appreciated.</p>
<p>Worked great for me. I even ziptied like the picture. Two caveats:</p><p>1) I postponed step 6 at first because it seemed like it wasn't necessary to test basic functionality. However, the &quot;gpio write 7 out&quot; was crucial; nothing happened until then.</p><p>2) 'gpio reset' hangs/crashes the pi. Any ideas?</p>
Thank you so much for this comment! I also skipped step 6 for the same reason and couldn't figure out what I did wrong. <br><br>I will try step 6 tomorrow and see if it works!
<p>Hi i follow this instructable and adapt to my case, thanks for it ;)</p><p>I have issues with power on the garage door:</p><p>-When the pi boot all is ok the door stay close but when i opened 1 or 2 times if the power is off the door (only the door) and back on the door open itself!</p><p>I did the trick with the &quot;garagerelay&quot; file and try to change the pin (wpi 9) and its always do the same things.</p><p>Does anybody know how can i solve my problem ?</p>
<p>i just find how to do, modify index.php and adding &quot;safe off the relay&quot; replace the &quot;first php code&quot;</p><p>&lt;?php <br> if(isset($_GET['trigger']) &amp;&amp; $_GET['trigger'] == 1) {<br> error_reporting(E_ALL);<br> exec('gpio mode 7 out');<br> usleep(1000000);<br> exec('gpio write 7 1');<br> usleep(1000000);<br> exec('gpio write 7 0');<br> usleep(2000000);<br> exec('gpio mode 7 in'); <br> }<br>?&gt;</p>
<p>Would this interfere with a multi-button Wall Panel where you can not only open and close the garage door, but also turn on light, or place your unit in lock mode? If i had a single button opener on my wall this would be straight forward. Please advise if you have any more insights here. thanks and great job! this is pretty darn cool.</p>
<p>If you have a multi-button wall opener, it probably connects by two wires to the garage door opener. You can connect your relay to the same two terminals on the garage door opener. It seems like when you press a button on the wall opener, it sends pulses to the garage door opener, but if you just short those terminals by closing your relay for a second or so, it makes the door open or close. The wall opener will still work normally, including the light switch.</p>
I having a Chamberlain multi LCD wall button with motion sensor. It also tells if power has been restored or battery backup is charging. Does time and temp and lights.<br><br>I went directly to the ceiling unit. I think the wall button LCD doesn't like being shorted. I sometimes get a message on the LCD saying something is miss wired. So I may need to add leads to actual button or solder leads on a wireless remote.<br><br>Anyone have any thoughts?<br>
<p>I have this issue too, looking for a workaround</p>
<p>Oh. Another not-as-tricky option (now that I've looked at your wall button thing) is to crack open the button itself and just find the two wires that go to the actual button itself, intercept those and connect them together briefly, see if that gets your door moving. There are probably eletronics of some sort between the wires that go to the button box on the wall and the wires that go to the actual button itself. At the end of the day, that physical button probably just latches two wires together for a bit. Plus, if you screw it up, those wall button devices are under $40.</p>
<p>Your best bet is finding two terminals at the opener that are for a normal open button. There's no telling what they are sending down the wires to any kind of fancy wall button control module- it could even be some kind of data and not a simple open/short operation. </p><p>If your model just doesn't have any other easy way to attach a normal button, your next best option (and this is a tricky one) is to figure out on the inside of the opener which relay is flipping to cause the motor to go. The rest of it (open vs close, stop when you hit the top or bottom) should be mechanically controlled-- between the fancy controller parts and the mechanical up/down/stop/start parts should be a single relay (maybe two) that kick off the open or close procedure. If you can find those (look for relays, measure their input voltage when the system is doing different things) and if you can control power to those externally (note that they likely are 120v coils so please don't kill yourself) then you can control the up/down. </p><p>This will void your warranty. Don't operate appliances of any kind with covers removed. 120 volts is enough to kill you if it hits you the right way. And remember kids, have fun!!</p>
<p>As kyle D, I get 404 not found error with the garage door opener website :/</p>
<p>does this have anything to do with the directories you are using? newer updates of apache moved the default directory to /var/www/html if I am not mistaken. I followed the instructions above and was able to get it working with only this small modification.</p>
<p>I had been wanting to make this project for months, and the wall switch for my garage door broke so that was my excuse to do this. I'm so excited to have a smart garage door opener. I made several tweaks to the code which can be seen on Github at https://github.com/JoshuaCarroll/Raspberry-Pi-Garage-Opener. Thanks for sharing your knowledge on this!</p>
<p>Thanks to the author for the great instructable, it really helped me get started! Additional tweaks I implemented were adding two reed (magnetic) switches to inform the pi when the door is either fully open or fully closed. My web page displays the status of the door in real time (via websockets), regardless whether the door is controlled by the app or other openers. I also have it send me a text message if the door has been left open for more than 5 minutes. I found node.js a good language to use for the software- it can host the website, control the door, listen to the sensors, send text messages and emails as you like when events happen, all from one running app.</p>
<p>I am also looking for that same status notification. Thank you in advance!</p>
<p>Hi ChrisG212,</p><p>Iam looking for the exact same functions. Any chance you could share yours ?</p><p>Thanks in advance.</p>
<p>I will plan to create an instructable when I get time since it is too many details to include in the comments area. I will provide a link here when I have completed it.</p>
Oh Nice ! I'm looking for this too, can you share please ? :)
<p>This is exactly what I am trying to do! Could you provide any more information please ChrisG212? Any help will be great</p>
<p>Hi there. Thanks for the tutorial. I built something similar but I wrote the server code in nodejs. Since I start the node server at boot I could add the initialisation code for the pins (to make sure the door stays closed at startup) inside the nodejs script. No need for a separate bash file.</p>
<p>THANK YOU for posting this - what a great system and guide! I built this two years ago and just had to re-build it due to an SD card failure. </p><p>Mine wouldn't work until I added a &quot;-g&quot; to the two commands in the /etc/init.d/garagerelay scripts as such:</p><p># Turn 7 on which keeps relay off<br>/usr/local/bin/gpio write -g 7 1</p><p>#Start Gpio<br>/usr/local/bin/gpio mode -g 7 out</p><p>I vaguely remember having to do the same thing 2 years ago. You might want to edit the instructions to include the -g, which as you probably know tells the Pi to refer to the GPIO pin number, and not the &quot;actual&quot; or numeric pin number. </p><p>Also, one other tip. The photos you show are for an older RPi Model A, which is fine. Personally I'm running on a Model B. You may want a note saying to refer to your own pin-out diagrams (and specifically the GPIO pins) if anyone is using a more modern Pi 2 Model B or B+, or even a Pi 3 Model B... </p><p>Thank you again - I am running this to provide access to an entire Club so they can open the access gate from their phones via wifi when the RF-remotes won't reach the base station. Now... the next project is for me to turn it into an app instead of &quot;just&quot; a local web server! (Hah, that's what I said ~2 years ago too...!)</p>
Also, I had to initialize GPIO as off, or zero, not 1 as in the example. After rebooting the relay was pegged and connected (causing the remote to trigger and open the gate), so I manually issued the gpio -g write 7 0 command, fixed the startup script with the &quot;0&quot;, and rebooted to confirm that it worked... which it did! Thanks again, and I hope some of this helps others as well!
<p>Completed the project but just one little issue that I found.I have a LCD garage door remote that has time/temperature and light option and when I leave it connected to the garage door and when pressing the button through the web interface the relay clicks all the time but sometimes the garage door won&rsquo;t open. When I remove the stock garage door remote wire from the garage door system everything works perfectly.I am assuming there is an issue with the flow of current and if I assume if I use a regular push button then it wont be an issue but in this case it is a LCD remote that has features on it and all running on one wire to the garage door. Anybody seen this issue and if so what did they do to fix it, I have a craftsman die hard garage door opener. Would I need an resitor somewhere? </p>
<p>So I set up and follow the instructions to do the Garage Opener. When I got through all the steps I wanted to test it and make sure it was getting the power when pushing the button. So before hooking it up to the Garage Opener I attached a small LED light to the wires and it appears that the LED is ALWAYS dimly lit/on. When the button is pushed, the LED gets brighter. Should I be concerned that the Pi is always pushing out some power?</p>
<p>Can anyone tell me why this happens. If the power in the house blinks, or goes out and comes on later, as the RasPi reboots the door will open with out a command from me. There have been times I come home and garage is open and i didnt do it, but can see the power blinked or went out. </p>
<p>Power spikes, line conditioner on the net router will help</p>
<p>See step #6 for explanation and potential solution.</p>
<p>I think, but don't quote me, if you used Pi GPIO pin 5 (wiring pin 9) instead of GPIO pin 7 (wiring pin 7) you wouldn't ever have the issue at all, because that pin has a fixed 1.8 KOhm pull up resistor on board.</p>
<p>This system needs a pull up resistor between the output pin(s) and pin 1 on the pi (3v3) to pull that pin high when the pi is starting up. That will fix the problem. Your step 6 will probably work about half the time. (if it works every time for you, there's someone else in the world that will find it works none of the times.)</p>
<p>If I plug the Raspberry Pi into the same outlet as the garage door opener head unit, are the power fluctuations (when the opener motor starts and stops) bad for the Pi? Has anyone else used that outlet without issues?</p>
<p>That called endrush, its caused when a motor or valves are energized.</p><p>You can get an in line filter/line conditioner from Radio Shack or electrical supply (MOV)</p>
<blockquote>Most relays including the one I purchased, operate like this - when the signal is ON the circuit stays off. When the signal is OFF then the circuit is on.</blockquote><p>I'm totally new to this and don't understand this part. I assume you have either NO or NC terminal connected to the garage door opener. If normally when the signal is ON, the circuit stays off and vice versa, can't you just switch the garage door connection from NO to NC or NC to NO?</p>
<p>Here's the thing about GPIO ports on a pi, or an arduino, or just about anything that has a GPIO port. They [typically always] start up as INPUT, not OUTPUT, which means they are waiting for you to ask if they are &quot;high&quot; or &quot;low&quot; (3 volts or 0 volts, or 5 volts or 0 volts usually, this depends on what system. High and low can mean a lot of different things here, but low is almost always zero volts referenced to the other voltage.) </p><p>Let's say that for the purposes of explanation our system uses +3 to mean high and 0 volts to mean low. Since the pins are just sitting there waiting for you to ask if it's high or low, they don't have 0 volts on them and they don't have +3 volts on them either, they are what we call &quot;floating&quot;. Now sometimes, it will be closer to high and sometimes it will be closer to low, but there are a lot of variables that can affect this (like static in the air even!) so if your relay knows to turn itself &quot;on&quot; when it sees 0 volts (low) and &quot;off&quot; when it sees +3 volts (high) and your pin is &quot;somewhere between 0 and +3&quot; then it might be close enough to one end to turn it on or close enough to the other end to turn it off. </p><p>So it doesn't matter if you use the NC or the NO, even if you reverse the logic in the software to make one way on and the other way off, you're still going to have this &quot;I'm not in an output mode yet so I'm somewhere between high and low&quot; problem and you're not really going to know for sure if the relay is going to be on or off. For our purposes though, we really should have it set up so that the relay is off *most* of the time, and just clicks on to &quot;press the button&quot; as it were.</p><p>The way we fix this, in electronics terms, is to &quot;pull it down&quot; or &quot;pull it up&quot; with a resistor. That's the fancy term, usually a &quot;pull-up resistor&quot;. It sounds complicated, but the reality is, you just connect the pin over to 0 or to +3 with a resistor. Just about any resistor will do. The resistor will drag that pin &quot;high&quot; or &quot;low&quot; (depending on if you connected the other end to high (+3) or low(0) when the pin would otherwise be in a floating mode. A lot of relays have a pull-up resistor built in, a lot of systems with GPIO pins have a way to &quot;turn on&quot; a pull-up resistor built into the hardware so that you don't even have to physically wire one in. But what about if the resistor is pulling your output pin to +3 and you need it to go to 0? That's easy, when you &quot;write&quot; to the pin and tell it to go to 0, that 0 has a resistance that is much much less (like, about 0 ohms) than whatever resistor you've put in so your resistor basically does nothing. It's like you trying to whisper to someone at a rock concert. (your whisper is the pull up resistor and the concert is the near zero-resistance connection that the system made when you said to go LOW.) Then when you write to the pin and tell it to go to +3 that resistance is also much much less than whatever resistor you've put in so it ignores the resistor then too. So the only time your pull up resistor does anything really is when the pin is in a state where it isn't high and it isn't low (remember, when it's &quot;floating?&quot;) so that resistor prevents the float.</p><p>In the author's case, it seems like most of the time (enough of the time) his float is in a certain direction so he's just counting on that to not change. But you really need a pull-up (or down) resistor (or a way to enable one built into the pi?) to make for sure you know if that pin is high (+3) or low (0). </p><p>On another note- if you're going to try this, you really need some basic security on the web server running on the pi. I guess if your home wifi is secured with something real (not WEP!) then that's a good start but you're basically giving access to your garage door to anyone with your home wifi password. Or anyone who plugs into your home wifi... which would probably be someone inside your house already... but this really should have an extra layer of security. I'm not a pi wiz or an apache wiz but since we're talking ethernet and mac addresses there's probably a not-too-complicated way to tell the pi not to talk to anyone except your known devices, by mac address. (mac addresses can be spoofed, but that takes more work than anyone who wants access to your garage is going to do unless you're keeping gold bars in there?)</p><p>If the pi uses 5 volts on it's GPIO (but I think it is 3) then change every +3 above to +5! :)</p>
<p>Well, I will share my Index and others files, as I added 2 relay to close door, you still need to make pin work at the start, also I have not yet tested, but trigger's working and returning the 1 and 2 </p><p>&lt;?php <br> if(isset($_GET['trigger']) &amp;&amp; $_GET['trigger'] == 1) {<br> error_reporting(E_ALL);<br> exec('gpio write 7 0');<br> usleep(1000000);<br> exec('gpio write 7 1');<br>}<br> else if(isset($_GET['trigger']) &amp;&amp; $_GET['trigger'] == 2) {<br> error_reporting(E_ALL);<br> exec('gpio write 2 0');<br> usleep(1000000);<br> exec('gpio write 2 1');</p><p> }<br>?&gt;<br>&lt;!DOCTYPE html&gt;<br>&lt;html&gt;<br> &lt;head&gt;<br> &lt;title&gt;Garage Opener&lt;/title&gt;<br> &lt;link rel=&quot;apple-touch-icon&quot; href=&quot;apple-touch-icon-iphone.png&quot; /&gt;<br> &lt;link rel=&quot;apple-touch-icon&quot; sizes=&quot;72x72&quot; href=&quot;apple-touch-icon-ipad.png&quot; /&gt;<br> &lt;link rel=&quot;apple-touch-icon&quot; sizes=&quot;114x114&quot; href=&quot;apple-touch-icon-iphone-retina-display.png&quot; /&gt; <br> &lt;link rel=&quot;stylesheet&quot; href=&quot;/css/style.css&quot; type=&quot;text/css&quot;&gt;<br> &lt;meta name=&quot;apple-mobile-web-app-capable&quot; content=&quot;yes&quot;&gt; <br> &lt;script type=&quot;text/javascript&quot; src=&quot;/js/jquery-1.10.2.min.js&quot;&gt;&lt;/script&gt; <br> &lt;script type=&quot;text/javascript&quot; src=&quot;/js/script.js&quot;&gt;&lt;/script&gt; </p><p> &lt;/head&gt;<br> &lt;body&gt;<br> &lt;div class='awrap'&gt;<br> &lt;a href='/?trigger=1'&gt;<br> Open<br> &lt;br/&gt;<br> &lt;a href='/?trigger=2'&gt;<br> Close<br> &lt;/body&gt;<br>&lt;/html&gt;</p><p>$(document).ready(function() {<br> $('a').click(function(e) {<br> e.preventDefault();<br> $.get(&quot;/?trigger=1&quot;);<br> $('a').click(function(e) {<br> e.preventDefault();<br> $.get(&quot;/?trigger=2&quot;);</p><p> });<br>});</p>
<p>Thanks for posting this. I do see two button, but they both trigger the same relay for me. Any ideas?</p>
Perhaps you got the PI pin's mixed up, the code look for input related to pins and then use that to fire the relay, each one have number, in my case 1 and 2<br><br>Some time back I made this now, but Im happy to share my files with you if you need,

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