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MM_Wombat
Senior Member

Joined: 12/12/2011
Location: Australia
Posts: 139

Posted: 02:09am 21 Jan 2013

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Hi all,

I want to connect the maximite to a computer power supply. 350W

The 12 V line and GND (comp psu) would connect into a regulated power supply(jaycar KA1797), that has a max output of 1A at 9V, which in turn would plug into Maximite power socket.

The 5V line and ground (comp psu), would plug directly into the daisy chained DMD's (Dot Matrix Displays), 9 currently, with 21 in pipeline, as per their respective connectors.

Pins 1 to 4 , and 7 to 9 connect to the DMDCON(nector)[seperate from power connector) for control of the DMD panels, using the command spiDMD().

Pins 15, 16 , GND, and 3.3V from Maximite will power the Wifly Module and com1: connection to the wifly....

Do I need to protect the pins from unwanted spikes/surges?

The main need for the computer PSU is for the DMD panels... 4,608 led's

Or will all be ok?

Regards Dennis

Keep plugging away, it is fun learning
But can be expensive (if you keep blowing things up).

Maximite, ColourMaximite, MM+

bigmik

Guru

Joined: 20/06/2011
Location: Australia
Posts: 2870

Posted: 02:16am 21 Jan 2013

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MM_Wombat said
The 12 V line and GND (comp psu) would connect into a regulated power supply(jaycar KA1797), that has a max output of 1A at 9V, which in turn would plug into Maximite power socket.

Hi Dennis,

Why not just supply the MM with the 5V supply via the USB connector.

No need then for the 9V PSU.

As to protection... if these displays are to bve used over any distance you could use Opto-Isolators ... I wouldnt worry about your WiFly though

Regards,

Mick

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

MM_Wombat
Senior Member

Joined: 12/12/2011
Location: Australia
Posts: 139

Posted: 02:27am 21 Jan 2013

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Hi Mick,

There is no computer motherboard. Only a PSU, NO USB to plug into. Is for an embedded controller type project, for an outdoor display. hence the wifly, to change text from inside the building..

Quote if these displays are to bve used over any distance

The display will need to be viewed from a distance.. Panel will measure 960 mm x 1120 mm.
9 lines of text x 16 characters
Regards Dennis..Edited by MM_Wombat 2013-01-22

Keep plugging away, it is fun learning
But can be expensive (if you keep blowing things up).

Maximite, ColourMaximite, MM+

VK2MCT
Senior Member

Joined: 30/03/2012
Location: Australia
Posts: 120

Posted: 10:41am 21 Jan 2013

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Hi Dennis,

I've used a pc power supply to power a MaxiMite.
I used the 5v standby PS output (on 20/24pin conn) to feed the Maxi via USB.
(Retrieved a 20/24 conn from old motherboard, and cut/sacrificed a USB cable).
The 5v standby power is usually used by a Mobo even when the power supply is 'off'.
I used a low power FET, controlled by a Maximite pin, to switch the power supply 'on' when needed - via green wire on 20/24 pin conn.
In my project this allowed external relays etc to be 'set' by Maxi, before main power was turned on.
regards,
John B
VK2MCT

bigmik

Guru

Joined: 20/06/2011
Location: Australia
Posts: 2870

Posted: 12:06pm 21 Jan 2013

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VK2MCT said

I used the 5v standby PS output (on 20/24pin conn) to feed the Maxi via USB.
....... cut/sacrificed a USB cable).

Thats a good idea to use the 5V standby and power the supply as required via a mosfet or transistor ....

The sacrifice a cheap USB cable was exactly the idea I had in mind for powering the MM.

Regards,

Mick

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

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