I always wanted to use my Galaxy s3 phone to open my gate or unlock my Front door. I just don't like the idea of carrying around extra remotes for such basic tasks.
Along comes the sainsmart rj45 8 relay device. Using their free app anyone can control devices that can turn on and off.
Please note that this system uses only wifi and not Internet. If you forgot to pay your Internet bill or your drunk neighbor ran down the pole with your Internet line, have no fear! Once you connect to your wifi you have the control you need.
Take a look at my other instructable on how to increase the range of a wifi router with internal antenna.
Also this remote is secure since a phone must have your wifi password in order to connect to the imatic. For example If you give a friend access to your imatic and somehow you don't want that friend accessing your device anymore, just change your wifi password! Super easy.
Step 1: Install the Sainsmart Rj45 8 Relay Device.
I used a 6inch pvc box to house the imatic device. It requires 5volts to power up. I soldered extension wires (not required!) to provide ease of installation for my future needs. Normally the imatic plugs directly into the 8 relay card. Once powered a blue led will blink plus leds on the RJ45 socket will light up when the cat5e cable is inserted.
My pvc box I stuck on the wall using double sided tape. Quick and easy.
Step 2: Install the App.
It's free and you can get for Android and ios. Install and it worked right off the bat for me. Just ensure your wifi router has 192.168.1.1 as it's address and no other network devices uses the address 192.168.1.4 since this is reserved for the imatic.
To control a device you just need to hardwire the relay contacts to the device you have in mind. I wired two relays, one for my gate motor and the other for my door solenoid lock.
The nice thing about using the phone as a remote is that you can password or biometric protect your phone and thereby have a safer universal remote.
Step 3: Modified App.
I really did not like a few things on the app.
1. The color scheme is not cool.
2. Having all relays on is a dangerous proposal.
3. I don't need to see links to buy the imatic again.
4. I'm an expert and don't care to see the guide on how to use the damn thing.
I butchered the free source code and made my custom version. It's much easier on the eyes in bright sunlight so now I'm pleased.
You now have my blessings sainsmart. :)
Update 19 April 2015.
Due to the sluggish behavior of the app, I have removed the imatic device and app from my home Control. I have replaced it with girder 6 and an infrared relay set. Please read my instructable on how I did it.