Project: 8 channel Relay Box

Discussion in 'The Completed Projects Collection' started by smching, Oct 26, 2012.

  1. smching

    Thread Starter New Member

    Dec 2, 2010
    9
    1
    This is a 8 channel relay box that the input connect to a controller allow it to control large loads like home appliances.

    I'm using this relay box for a snooker centre to control snooker table lamps. The lamps consists of 6 pieces 20W and 3 pieces 10W fluorescent lamps, total of power consumption is 150W per table.

    Material:
    PVC BOX
    DIN Rail
    2A 12 DC adapter
    Omron MKS2P relay x 8
    On/Off Swith x8
    Relay Socket
    ULN2803 IC
    18pin Swiss machined socket
    PCB with copper hole
    Pin Header connector
    Wire/IDE cable or Floopy drive cable
    Key Switch

    Finish product shows 10 on/off switch. I'm using only 8 of them, 2 of them reserved for future use.
    [​IMG]


    Block diagram
    [​IMG]


    Connection diagram
    [​IMG]


    The relay is control by an ULN2803 line driver. As shown in figure below, I'm using Swiss machined socket for the ULN2803 since the ULN2803 can generate heat & require more current on it especially on pin9 (Gnd), but I agree the best thing is a solid soldered connection.
    [​IMG]

    To turn on relay manually, on/off switch must connect between the output of ULN2803 and relay coil. See figure below on how to adding on/off switch and indicator to the circuit. This is very useful when the controller is not able to control the relays while still want to turn on the lights.
    [​IMG]


    Figure below shows 10 units on/off switch fixed to the cover, I'm using only 8 of them, the other two is reserved for future use. A key switch is use to prevent manually turn on the relay.
    [​IMG]


    More pictures and instruction available at
    http://ediy.com.my/index.php/projects/item/43-8-channel-relay-box
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Interesting project. I'm not sure how I would use it, but I suspect someone will.

    I'm more of a fan of SSR's. Relays have their uses though, they tend to be tougher in use, though they can wear out over time.

    Nice job. Any thoughts where you would like to put this article in the index?
     
  3. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    This project while simple its function seems to be well documented. I can't make out what role the Arduino plays in this project. I also could not locate the source code for the project. If it is buried in a link then I totally missed it.

    hgmjr
     
    Last edited: Nov 4, 2012
  4. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Actually I noticed that, and I was going to mention it. We really do need the Arduino schematic and programing hosted locally, this is a firm requirement for posting on this forum. If it isn't in a month or so I'll move it to the Projects forum. The other submission is also in limbo because of the lack of local documentation. If you want I will move it to the Projects forum so you can work on it. Members require 10 posts or more to be able to edit old posts.

    I'll remove this post if the requirements are met, but meanwhile please note the rules for posting a complete project. While links are OK, in and of them self they are not acceptable.

    Please read the rules of the Completed Projects forum.

    To repeat what I have said:
    All documents must be hosted locally. AAC allows for attachments and albums, use them. You Tube video links allowed, but they in no way constitute proper documentation.
     
  5. smching

    Thread Starter New Member

    Dec 2, 2010
    9
    1
    The Arduino is do nothing here, it use to show that the relay box must connect to the controller and allow it to communicate with the controller.

    You don't have to use an Arduino, you can use any other device as a controller.

    I think I should remove the Arduino from the picture. Thank you for your feedback.
     
    Last edited: Nov 5, 2012
  6. smching

    Thread Starter New Member

    Dec 2, 2010
    9
    1
    I'm first time posting article in this forum. May be I had missed out something.

    I though I want to upload all the pictures to this project, but this fourm limited me to upload only 6 pictures. Is there a way that I can upload more pictures.
     
    Last edited: Nov 5, 2012
  7. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Yes, start a second post. The limit is 6 per post.
     
    smching likes this.
  8. MMcLaren

    Well-Known Member

    Feb 14, 2010
    759
    116
    Are the switches SPST (single pole single throw) type rather than momentary type? If so, then it seems you don't need the Arduino or the ULN2803 and your project is really just a key switch, eight lighted SPST switches, and eight 12 volt relays, is that correct?
     
  9. smching

    Thread Starter New Member

    Dec 2, 2010
    9
    1
    I'm using the Arduino as an example of controller, you can use any device as the controller.

    Actually you need the ULN2803 since most of the controller cannot connect directly to the Relay. Another reason is the controller is using 5V and the relay is using 12V.
     
  10. MMcLaren

    Well-Known Member

    Feb 14, 2010
    759
    116
    Your project presentation then is a switch controlled eight channel relay box which includes a ULN2803 interface for a microcontroller. Is that correct? If so, it would seem that any individual switch left in the "on" position would energize its associated relay and over-ride any microcontroller control of that relay channel. And so, if a user wants to control all of the relays using a microcontroller he/she would have to make sure all of the switches were left in the "off" position, yes?

    Very nice job on the relays and enclosure...
     
    Last edited: Nov 6, 2012
  11. smching

    Thread Starter New Member

    Dec 2, 2010
    9
    1
    Yes, you are correct. The purpose for the on/off switch is for emergency use, user can manually turn on the relay when the controller is not functioning.

    I'm using this relay box to control snooker lamps, when the snooker lamps is turn on, the rate counter is start to count money:D Sometime the snooker lamps including the snooker tables (everyday need to clean and the environment is very dark) require to maintenance, therefore it must turn on manually (provided the key switch must turn on) without start the rate counter.
     
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