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nnvpaul
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Joined: 12/12/2014
Location: United States
Posts: 7

Posted: 04:19pm 19 Dec 2014

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I have a maximite colormax2. I want to use an 8 channel relay board that requires 5v. I plan to power the board with its own power supply. I am not going to power it through the computer. The maximite only puts out 3.3v. What is the easiest way to step it up. There seems to be several ways of doing it and I am not sure what I should do. I have heard that pull up resistors are easy and will do the job but I don't know how it works or what to get or how to do it. I would assume that I would need a resistor for each pin and I would assume that the current draw would not be an issue because the relay board has its own power supply. Can someone help me with this. Thanks.
Paul

bigmik

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Joined: 20/06/2011
Location: Australia
Posts: 2949

Posted: 05:25pm 19 Dec 2014

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Hi Paul,

It depends on how the relay board you have is driven..

It is quite possible, read LIKELY, that the 3v3 output would be sufficient to drive the relay board which would presumably have a transistor or Opto coupler driver embedded in its design.. (you may need to add a resistor in parallel to the one on your driver board but you may get away without that.)

If you wish to direct drive the relays then you will need a simple transistor switch in between the MaxiMite and the relay board.

Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

OA47

Guru

Joined: 11/04/2012
Location: Australia
Posts: 982

Posted: 07:28pm 19 Dec 2014

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Paul, instead of setting up 8 transistors, I have used the ULN2803 IC that is a ready and simple way of linking the mite to the 8 relays. The IC has all the components needed as well as diode protection from the relays.

GM

bigmik

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Joined: 20/06/2011
Location: Australia
Posts: 2949

Posted: 11:52pm 19 Dec 2014

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Paul,

If your relay board is like this one I think you could more than likely direct drive it with the 3v3 output pins as it is driven via Opto isolators..

Ebay Board

If they work as a LOW to enable the relay then certainly it would work but if it is a High to enable the relay then you `may' need to reduce the resistor on the LED side of the OPTO Isolator, but even then I reckon it would most likely work without modification.

Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

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