Go Down

Topic: voltage drop (Read 684 times) previous topic - next topic

groundsman

Hello.
I have just completed my scoreboard project, which consists of 3 units a treble a double and a single. I have used one ardruino uno, 6 sparkfun TPIC6C596 shift registers. The shift registers are all linked together though the 3 units. The power to the arduino is 12 volt from a transformer. My problem is the first unit which is the single is fine but as the chain progresses I am losing voltage so when I get to the treble unit I have lost 2 volts so the lights are not as bright. I thought I would feed each unit with its own power supply from the transformer. this worked the lights brightness and the voltage where all the same. But what happens is the numbers change but are erratic ( the control is though buttons) Any ideas what is wrong and what I can do to cure this problem.
Thanks Eddie.     

ReverseEMF

#1
Jun 11, 2018, 08:45 am Last Edit: Jun 11, 2018, 03:43 pm by ReverseEMF
Please read this, and then update your post:

How to use this Forum

[fixed the link]
"It's a big galaxy, Mr. Scott"

Please DON'T Private Message to me, what should be part of the Public Conversation -- especially if it's to correct a mistake, or contradict a statement!  Let it ALL hang out!!

groundsman

I have clicked the link but It will not open.
Eddie.

ChrisTenone

It's at the top of every subforum page, this link should
work:

http://forum.arduino.cc/index.php/topic,148850.0.html

Are the ground wires of all the power supplies and the other components all hooked together?
Atmosphere carries combustion vapors to places where they will do good instead of harm - Mike Faraday's 'History of a Candle': https://www.youtube.com/watch?v=6W0MHZ4jb4A

Whoops ::)

falexandru

When you open the General section of the General electronics, there is a "topic" called "How to use this forum".

That section lists some reccomandations that increases the value of the experience of using the forum.

Basically, it is about how to fully describe the problem, to post schematics and full description of what somebody intends to do or what was the problem.

It is sometime difficult - from my personal experience in the forum- to find descriptions of some actions. But at least by attempting to use the commands one can ask for assistance in a more precise way. The experienced people here are very kind and supportive, I can tell from my personal experience.    

groundsman

Hi
Eddie.There are 2 ground wires. One is from the buttons and one from the shift registers. They both go to the ardunio and then back to the power supply that feeds the arduino. All the ground wires on the shift registers are linked together.
Eddie

Shuzz

May I suggest that you draw up a schematic and post that together with your code?

Otherwise we'll only be shooting in the dark.

Also, please describe in as much details as possible what you mean by "erratic behaviour" in the numbers.

srnet

Describing and providing a link for the 'units' would be helpful too.
$50SAT is now Silent (but probably still running)
http://www.50dollarsat.info/
http://www.loratracker.uk/

NoraTheDoggo

As said before there is not much to go in with this topic. I have included a wiring schematic for three shift registers just remember you may need to change the data clock and latch pins based on you code.
I like cooking children and Arduinos
Is not the same as: I like cooking, children, and Arduinos
Grammar matters!

groundsman

Hi I will drew up my schematic drawing and code and post it.
Eddie.

NoraTheDoggo

Hello.
 My problem is the first unit which is the single is fine but as the chain progresses I am losing voltage so when I get to the treble unit I have lost 2 volts so the lights are not as bright.    
Just a quick troubleshooting idea: are your LEDS are connected to one resistor? If so split them up and use three or four.
I like cooking children and Arduinos
Is not the same as: I like cooking, children, and Arduinos
Grammar matters!

TomGeorge

#11
Jun 13, 2018, 11:37 am Last Edit: Jun 13, 2018, 11:38 am by TomGeorge
Just a quick troubleshooting idea: are your LEDS are connected to one resistor? If so split them up and use three or four.
An example of how you connect LEDs to TPIC6C596,

Tom.. :)
Everything runs on smoke, let the smoke out, it stops running....

groundsman

My leds are in strips and each led has its own resistor. My TPIC6C596 shift registers are produced by sparkfun so they are different to your drawings. If you look on there web page you will see what I mean. I followed there drawings.

TomGeorge

Hi,
Does each display module have its own separate power supply wires directly back to the display power supply?

Don't daisy chain the power wires as this will produce your symptoms.

Does the voltage at the powersupply terminals drop, or just the display modules?

Can you post a diagram of how your power supply is distributed please?

Tom... :)
Everything runs on smoke, let the smoke out, it stops running....

groundsman

Hi Tom George.

I have attached a drawing and hope you can understand it.
If I take a voltage reading before connecting the to the arduino I get 12.4 volts. when I connect them it comes down to 11.4 volts. Should I connect each shift register with its own power supply?
Eddie.

Go Up