Using an Android Phone to Control Real World Appliances - DECOMMISSIONED.

Introduction: Using an Android Phone to Control Real World Appliances - DECOMMISSIONED.

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 as it's address and no other network devices uses the address 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.

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    Question 4 years ago on Step 2

    Hi, iMatic doesn't connect to my network.

    I receive an error message stating "check network connection..." However the TCP Relay works fine via WEB?

    How can I fix the problem?


    7 years ago on Introduction

    Last week I bought the Sainsmart Imatic and it works really beautiful.

    But I would like to customize the android app, Can you Please tell me how you did it?

    I have some experience with making android apps, but I do not succeed to change the layout of the Sainsmart app in the Android-studio.

    Thanks in advance.


    Reply 7 years ago

    Hi. I had severe difficulty in customizing that app. I used apk editor pro. It is very time consuming. All in all I have decommissioned my Imatic. I am no longer using that device. It has been replaced by an infrared relay set and girder 6. This new setup is far more reliable than the imatic. I can no longer Recommend the imatic due to the very unstable app behavior. Check my instructable on opening my home with girder 6 and an android phone.


    7 years ago

    This is a very nice concept and may be useful in the future. The description by the poster is very good. The problems that prevent it from being useful now are the fault of the board manufactuer.

    The hardware imlementation by the relay board manufacturer is incredibly flawed. The idea of forcing the router to a fixed address and forcing use of a fixed IP for the board was ok 20 years ago but not today. At a minimum the board should default to connecting using DHCP, which tells the device where the router (gateway) is and assigns an IP address to use. The hardware manufactuer cannot reasonably expect all users to change their router address, even if they know how.


    Reply 7 years ago

    Ah my friend. That is by no means the real problem with this device. If you turn off your phone wifi then turn it back on the app goes into an error state. Restarting the phone does not fix the problem. Only cycling power to the hardware board will clear the issue. I actually reset the device 0.1s every 30s using my home controller software. It's a nag yes but it works for me. The fixed ip is a low cost approach but I have no problems with it. The same manufacturer does offer newer variants than can accept new ip addresses and ports.