Calculating Power Supply for a Project[LDR Target Shooting]

Using Arduino Project Guidance
1

Hello guys!

I develop many projects using arduino but power supply is always one big question for me. I am always afraid to put a large amount of current in my arduino and blow his regulators. I would like to know how you guys manage to calculate the ideal power supply, and how to provide that energy to all elements involving the project.

For ex, I am current working on a Target Shooting with LDR. There are 6 LDR each with his respective servo, every time one random pair of servo/LDR is selected to be aimed with a laser, when it hits other pair is selected. I also have two 4 digit BCD display that show time and score for the player. All servos are connected in a protoboard and the 5V arduino output is supplying their power.

So the project have:

  • 1x Arduino Mega
  • 6x Servos
  • 7x LDR(6 for target, and 1 to start the game)
  • 2x 4 digid BCD display
    For now I am using 2 power supplies at the same time: one Android charger in the USB port of the Arduino(5V-2A) and one standard 5x2.5 power supply(12V-1A). The problem is one of the servos always have trouble to go UP, as if there is no enough current to make him move.

So what do you guys think? I need to change to a 3.5/4A power supply? Should I just put a exclusive supply for all the servos?

Also, any general tip on power supplies for Arduino projects?

Thanks!(Also, sorry for any english mistake, not my first language)

2

Hi Davi,

Very nice description and write up. We have something similar to this at a local sporting store called Outdoor world. It makes shooting sounds and makes bell sounds also when it registers a hit.

Please include even more detail. Servos, wiring diagram or schematics, pictures, codes... It is hard to respond to a specific problem you are having without enough information...

Thanks

3

If only one servo moves at a time, then the current rating you need is that + say 200mA for the other stuff.

If a beefier power supply helps is hard to say without knowing how much current the servos draw.

You can measure the maximum current draw with a multimeter

4

daviunifei:
Hello guys!

I develop many projects using arduino but power supply is always one big question for me. I am always afraid to put a large amount of current in my arduino and blow his regulators. I would like to know how you guys manage to calculate the ideal power supply, and how to provide that energy to all elements involving the project.

A power supply will only supply the amount of current that the load needs.
A 5V 2A supply will output 5V at any current below 2A.
A 12V 10A supply will output 12V at any current up to 10A.
If you are afraid of damaging a controller due to over current, then I suggest if you are developing many projects, you purchase a power supply with variable voltage and variable current limit.
Although somewhat expensive it will be well worth the effort and addition to your workbench.
Tom..... :slight_smile: