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GMenv1
Innovator
1,327 Views

Avoiding Electrocution using Grove Relay - Feedback needed

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Good morning,

While the French healtchcare system is good, I'd love to avoid having to use it because of pesky power/wattage issues.

 

I am putting together a demo and would like to use the Grove Relay (https://www.seeedstudio.com/Grove---Relay-p-769.html Grove - Relay ) in conjunction with a light that is hooked up to the power (220 v outlet).

Looking at the doc on the Grove site leads me to think it should be ok but...

  • Here (http://johnny-five.io/examples/relay/ JavaScript Robotics: Relay with Johnny-Five ) they mention not using devices more than 24v
  • From what I recall, if a relay is off, the power is then "stored" (to simplify things, don't quote me) in the coil. Looking at the size of the relay, wouldn't be a recipe for disaster and frying a board?
  • What if use the power-switch on the light as the primary on/off controller, the Edison being the secondary.
  • The few instructables out there either use a low voltage battery or nothing at all (meaning no connection to a real powered device) so not much to go with.

 

Has anyone tried using the relay with a real power output or are we indeed limited in how much power can go through the board without toasting it?

Ideas + advices are welcome

Thank you!

 

Gregory
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1 Solution
idata
Community Manager
65 Views

Hello Gregory,

I will try to help you use the relay in order to avoid any accidents. According to the relay's picture found in https://www.seeedstudio.com/Grove---Relay-p-769.html https://www.seeedstudio.com/Grove---Relay-p-769.html, it has a 3VDC coil and its contacts can support up to 250VAC/10A or 30VDC/10A.

So, what you read might have been recommendable when using DC but if you are using AC (as I believe you are doing), you should be safe connecting 220VAC.

The relay also mentions that if you are working on 250VAC, it is not recommendable to surpass 7A, nevertheless if you are just using a light bulb, the current shouldn't even get near that number. Anyhow, you should keep this in mind to avoid any eventuality.

Regarding the third point you mentioned above, what would happen would be that you would interrupt the circuit in two points. This means that the light would only be on when the light switch is closed and the relay in active.

About the fourth point you posted, I don't understand what you mean, could you please specify?

If you connect the relay correctly to both the board and the light, you shouldn't worry about burning the board as both circuits would never get in contact with each other. However, you must always be very cautious when working with power circuits.

Let me know how it goes.

 

Peter.

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5 Replies
idata
Community Manager
66 Views

Hello Gregory,

I will try to help you use the relay in order to avoid any accidents. According to the relay's picture found in https://www.seeedstudio.com/Grove---Relay-p-769.html https://www.seeedstudio.com/Grove---Relay-p-769.html, it has a 3VDC coil and its contacts can support up to 250VAC/10A or 30VDC/10A.

So, what you read might have been recommendable when using DC but if you are using AC (as I believe you are doing), you should be safe connecting 220VAC.

The relay also mentions that if you are working on 250VAC, it is not recommendable to surpass 7A, nevertheless if you are just using a light bulb, the current shouldn't even get near that number. Anyhow, you should keep this in mind to avoid any eventuality.

Regarding the third point you mentioned above, what would happen would be that you would interrupt the circuit in two points. This means that the light would only be on when the light switch is closed and the relay in active.

About the fourth point you posted, I don't understand what you mean, could you please specify?

If you connect the relay correctly to both the board and the light, you shouldn't worry about burning the board as both circuits would never get in contact with each other. However, you must always be very cautious when working with power circuits.

Let me know how it goes.

 

Peter.

View solution in original post

GMenv1
Innovator
65 Views

Thanks Peter. I'll give it a shot in the next few days and will even make a video of it just for fun (so if it will be memorable if there is a short )

As to my fourth point I was merely saying that all the examples on the web (often found at instructable.com) stopped at the point where a real device (say a light bulb) was hooked up to the system.

Thank you!

 

Gregory
idata
Community Manager
65 Views

I understand, I hope the information I posted above helped to clear your doubts. I look forward to hearing how your project goes. In case you have any other doubts, please let us know and we'll try to help you in any way we can.

 

 

-Peter.
GMenv1
Innovator
65 Views

Thanks for the advice + ideas, it worked out really well for our demo. If you are interested here is the built + project we did

https://www.smartnotify.us/MainSite/NewBranding/Blogs/ViewBlog.aspx?id=559 How to: Building an IoT demo for Esri Sig2016

 

Gregory
idata
Community Manager
65 Views

I'm really glad to hear that, thank you for sharing your project with the community.

 

 

If you ever need help, please don't hesitate to come back to the community.

 

-Peter.
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