SEEED Studio / Arduino -- 5V Relay module (Digital) -- Electronic Brick

Working with the digital relay to control high voltage can be hard to understand.  There are no instructions on how to make this perform with an ARDUINO.  I created this so people will be able to use the relay with a standard 110 volt house outlet in either NO - NORMALLY OPEN  or NC - NORMALLY CLOSED modes.  As always working with high voltage is dangerous so be careful.  If you do not understand how it works seek help from someone who knows how to make it work or DO NOT ATTEMPT THIS INSTRUCTABLE !!!!!!



UNDERSTANDING RELAY STATES:

You can configure your ARDUINO signal to be either "LOW" or "HIGH".  It does make a difference as to how the RELAY controls the outlet in the "NO" or "NC" states.  For this project all PINS on the ARDUINO will start out in the "LOW" state as the default.  You need to determine how you need your "OUTPUT" PIN to be configured for your own projects.  You need to understand this concept so you can configure your projects using this RELAY BRICK to be the most effective with the least amount danger possible.


NO - Normally Open

The RELAY can be NO (Normally Open) state . When outlet is pluged into a high voltage power supply the outlet is HOT (power to it and LED on outlet is on).  The default mode at the ARDUINO is in the "LOW " state (RELAY LED light is off). When ARDUINO send a "HIGH" command to the RELAY (LED on RELAY turns on) all power is cut to the outlet  (LED light on outlet will go out).

POWER LOST DURING USE:
When power goes out or power cord is unpluged there will be no power to the outlet or ARDUINO and all devices connect will not work.

RELAY "LOW" (LED on RELAY is off) and power is lost to the ARDUINO and RELAY outlet will remain HOT.  What ever device is connected to the outlet will continue to run.
 
RELAY "HIGH" (LED on RELAY is on) and power is lost to the ARDUINO and RELAY the outlet will revert back to a HOT condition.  What ever device is connected to the outlet will be turned on again.




NC - Normally Closed

The RELAY can be NC (Normally Closed) state . When outlet is pluged into a high voltage power supply the outlet has no power and is OFF (power to it and LED on outlet is off).  The default mode at the ARDUINO is in the "LOW " state (RELAY LED light is off). When ARDUINO send a "HIGH" command to the RELAY (LED on RELAY turns on) power allowed to flow to the outlet  (LED light on outlet will turn on).

POWER LOST DURING USE:
When power goes out or power cord is unpluged there will be no power to the outlet or ARDUINO and all devices connect will not work.

RELAY "LOW" (LED on RELAY is off) and power is lost to the ARDUINO and RELAY outlet will remain OFF (LED light on outlet is off) .  What ever device is connected to the outlet it will continue to be off.
 
RELAY "HIGH" (LED on RELAY is on) and power is lost to the ARDUINO and RELAY the outlet will revert back to a OFF condition.  What ever device is connected to the outlet will turn off as power to the outlet has been lost.


Know what you can drive with this RELAY:
current * voltage = power 
This RELAY is rated for 10A at 120V
The RELAY can handle up to a 1,000W device.
It is not a good idea to run this RELAY at a full 1,000W demand.  It is a better idea to stop at about 800W to be on the safe side. 

Step 1 COMPONETS OF PROJECT

There are 4 major componets to get this project to work correctly:

1 - Arduino of some type to control the relay.

2 - 5V Relay module (Digital) -  Electronic Brick
      It is much easier to use this small foot print digital relay with all the correct parts in one unit.
      Building one of these little guys can be a lot of work and not perform as well as this unit.

3 - House Outlet the the relay will control

4 - The Sketch to drive the relay using an Arduino.
      (if you don't understand how to use sketches with an Arduino, you will need to learn this skill).

Comments

[City Lights]

.
I agree with the others, you have NC and NO labeled backwards.

I also noticed you used a lower gage wire from your terminal block to the relay brick and back again (the HOT/black line). It looks a little under rated for a 10 Amp max relay. I use #12 Solid copper for such interconnects, but #14 gage should be fine. #14 solid is the standard 15 amp wire gage used in NA - North America. #12 gage is NA standard for 20 Amp service. The Lower the gage number in wire the smaller/thinner the wire and the Less Current it can carry before heating up.

Also remember that when a Load (power device) is switched on there may be a rush (Peak) in amps that exceeds the 10 Amp Continuous rating of the Relay. This is normal but is one of the reasons I would never downgrade my wire gage.

I would suggest to anyone playing with circuits that switches house main voltage to install a ARC Fault breaker at the panel or somewhere before your custom monkey business! This Is Not the same as a Ground Fault which saves You from getting electrocuted. Most electrical fires are started by Arcing. A small arc over time will carbonized where the electrical bounding has been broken or poorly made. Once carbonized, heat increases and increased heat can lead to Fire. Arc Fault Circuit Interrupters Saves Lives from Fires! ..and property and insurance hassles :) so play it safe and Happy automating!

[doctek]

Be very careful putting high current through this board! Even though the traces are short, they are no where near 14 gauge. Trying to put 10A at 12V vaporized the trace between the relay and the output connection. If I had taken the time to look at the thickness (thinness?) of the traces on the board I would never have done this.

Be warned.

[arduino man]

If any one would like some cheap handmade arduino bricks
pleas go to my etsy shop 111swords.
I would greatly appreciate it.

[TerryKing]

This relay and other similar ones in 4-relay and 8-relay boards are available here:

http://¡.ws/relays

There's lots of information on power control with this relay and others here:

http://arduino-info.wikispaces.com/ArduinoPower

Regards, Terry King

[e-mail]

[rik]

Thanks Terry,
I will check these sites out. Always good to learn new things.

Rik

[City Lights]

I would not use the 5V from the Arduino due the the current draw of the relay. I would use a separate 5V supply.

[mitsubob8404]

Great instructable; however, the open/close descriptions are backwards for electricity BUT not for water-

Electricity - Open circuits are not continuous, meaning there is an 'opening' or separation between one connection and another.

Water - An open valve is one in which the gate has been shifted as far away from the flow of water as possible (hence the phrase 'Turn it wide open' meaning 'to allow the maximum flow of water/fluid through')

Hope this helps!

[rik]

mitsubob8404 -- Thanks for the input. I am new to electronics and understanding how these bricks work with the correct terminology.  What would be the correct way to state the change I need to make?  If you could help me on this I will make the change, so others will not make the same mistake I have made.

Thanks so much for your input,

Rik

[8bit]

You have normally open and normally closed backwards. When a circuit is open, no current can flow. The circuit is "off." When a circuit is closed, the power is on.

[rik]

thanks for pointing that out. I will check with the Seeed Studio tech person on this, as they have reviewed this and had no changes as is. I can make the changes. Thanks again, rik