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Help with my University Project !!

TechTyro

Aug 26, 2017
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Aug 26, 2017
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Hi guys. I am currently working on a simple project for my university. The project is to display time, date, day, temperature and humidity in a large led board. I have made the display using three 16x32 p10 led boards connected in series. I have used arduino uno as the controller to process and send data received from RTC 3231 module (time and date) and dht 11 sensor module (temperature and humidity). To power up the led boards, I have used a 5V 10A power supply unit. Everything is working fine till now....

The problem is that I was asked to extend the project and make 3 more of the same to make the display 4-sided. I want to display the exact same data on all the 4 sides of the display. I can buy 9 more led boards and power supply for the same and make the display, but can I use the same arduino to get parallel data lines for all the 4-sides ?? Will the arduino be able to produce sufficient current to send correct data to 4 parallel data buses ?? Please Help....I have attached some pictures showing the backside of a p10 module, the connections I have used for connecting arduino to the display (which has a 16 pin input) and the project which I have made.
 

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kellys_eye

Jun 25, 2010
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'Fan out' would be the usual specification t look for but that doesn't seem to exist for the Arduino. But given you can drive a 20mA LED directly you should be able to determine the drive capability from the information associated with the 'input' of the display logic board(s).

Having said that, buffering is a straightforward exercise in itself.
 

Irv

Jun 7, 2017
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Jun 7, 2017
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You also have to consider the maximum that can be drawn by all ports combined - which, I think, is less than you would get by multiplying 20mA by the number of ports. IOW, not all can be used at the same time, if you're drawing the recommended amount from each of them. Buffers are the answer.
 

TechTyro

Aug 26, 2017
10
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Aug 26, 2017
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Thank you guys for the reply. I will surely check the total current drawn by the input port. Can you give me a more detailed explanation on how to use buffers??
 

kellys_eye

Jun 25, 2010
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The term 'buffer' refers to any device that can increase the drive voltage or current with little/no effect on the source signal.

You can get inverting and non-inverting, logic level, open-collector etc etc so as far as 'buffering' is concerned you can drive anything - a few extra LED boards should pose no issues at all.
 

Irv

Jun 7, 2017
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Jun 7, 2017
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We want photos or videos when you're finished!
 

TechTyro

Aug 26, 2017
10
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Aug 26, 2017
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It worked ! All I did was just connect the data lines in parallel using a breadboard and fed them into the 4 sets of led boards. Apparently, the Arduino was able to provide sufficient current to all the data lines with just a 5V 1A rated power supply. The only problem was that there was some flickering in some of the boards which was frustrating to look at. Later, I found that the problem was either with the AC adapter or the power supply port present in the Arduino and fortunately the flickering stopped when I used a mobile charger with a USB port to power up the Arduino. Apparently, the USB power supply was more regulated and stable than the power provided by the AC adapter to the DC barrel plug.

I have posted a few pics with all used led boards. My next step towards completion is to design a PCB which does what the temporarily used breadboard does, which I believe is not a big task. Thank you for your responses guys.
 

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