Saturday, 29 November 2014

Android-Arduino Controlled Eight-Relay Board

via Blue Tooth  Part I

Eight-Relay Module 
control the relays using a smart-phone or tablet.

In an earlier series of posts [] I described a project to design and build a remote controlled relay board, using Jee-lab's Jee-nodes. In this update I am adapting the design to work with Android and Java via a blue-tooth (BT) link to Arduino. NB some of the information from those posts will be repeated if I think it may help for safety or help makes things clearer.

So I am adapting the remote control device I made earlier to work over BT. It allows me to independently switch eight relays and control various  items. When I use buttons on an Android device, instructions will be transmitted via Blue-tooth. At the other end, Arduino switches the relays ON or OFF.

I used a relay module identical to the one in the picture above. It's an optically isolated 8-relay module. That's nice because it makes controlling it easy with an Arduino.  It's worth while reading this link before starting: 



I will not be posting how it is possible to link relays to AC mains devices. I will be using low power DC examples. If you go ahead yourself and try mains stuff, remember I told you it can be very dangerous. Playing with mains power can kill you, and the people around you, not just by electrocution but also by starting a fire. 

I didn't need full isolation, so I kept the Vcc and JD-Vcc pins connected using the jumper on the board. I wouldn't use more than 4 relays working at once in my Firework firing RC device. If you intend to use more than four relays at once, then you need to use a separate power supply for the relay coils. This is because the 5v supply can be damaged by the current needed to operate all at once (8 x 80mA = 640 mA ).

You can use a separate 5v supply for the relays, so long as that supply is capable of more than 640 mA. [NB USB should not exceed 500mA].

If you require a separate power supply for the relays follow: Optically isolated 8-relay module instructions with respect to the JD-Vcc jumper and ground connections.

So, relay board tested and working - time to adapt and update my Arduino code!

also see this link: 


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