Connecting an Arduino Uno to a powered breadboard

Hello,

I am trying to connect my Arduino Uno to multiple devices. I believe these devices will cumulatively pull more current than the Arduino’s 5v pin can supply, so I am investigating alternatives.

The first thing I am trying is using a MakerSpot Breadboard Power Supply Board Module
(Amazon Link). It is powered using a 9 volt wall wart.

I am trying to connect this electromagnet device to the powered breadboard. When I connect it directly to the Arduino, as shown in the diagram, everything works fine. When I connect the GND and VCC pins to the powered breadboard, but leave the SIG pin directly connected to the Arduino (digital port 3), it does not seem to work.

Is there something I am missing about how this circuit needs to work? My multimeter verifies that I am getting 5 volts out of the power supply. I have tried eliminating the breadboard and just connecting to the power supply module’s 5v and GND pins, but that did not help either. I am basically just using the sample code for the electromagnet, so there’s nothing too complex in the code.

Do you have a common ground? The GND that goes from the breadboard to your device also needs to go from the breadboard to the GND of the Arduino.

Further, the power rails on the breadboard might be interrupted halfway the board; double check that.

fr0:
I am trying to connect my Arduino UNO to multiple devices. I believe these devices will cumulatively pull more current than the Arduino's 5v pin can supply, so I am investigating alternatives.

You are correct there, but regrettably the module you cite is as equally useless as a 5 V power source, as the UNO itself.

And when you post a link, please do not click the "Prevent this page from creating additional dialogs" checkbox; this is just a nuisance for people trying to follow the links.

The electromagnet module is very poorly documented; the circuit and actual specifications are not given. It incorporates a switching transistor and the suggestion given that it draws a "maximum" of 300 mA and operates at 5 to 12 V implies that it draws 120 mA at 5 V.

This in addition to the operating current of the Arduino itself is going to be too much over time, for the regulator on board the Arduino UNO or that little "Breadboard Power Supply Board Module". You need a proper regulated 5 V supply for both the UNO and electromagnet.

But it does sound as if you have forgotten to connect the grounds of the two systems together. :roll_eyes:

Post a photo of your breadboard connected to the
breadboard power supply which has it's own piwer rails.
Also, what is the voltage on the arduino 5V pin ?

Paul__B:
This in addition to the operating current of the Arduino itself is going to be too much over time, for the regulator on board the Arduino UNO or that little "Breadboard Power Supply Board Module". You need a proper regulated 5 V supply for both the UNO and electromagnet.

Do you have a suggestion for a proper way to power my system (assuming I will have about 3 devices that have similar power requirements to the electromagnet)? I am very much a beginner, and I can solder, although I prefer simple plug-and-play options. I also prefer to stay away from dealing directly with AC wall power for safety reasons.

But it does sound as if you have forgotten to connect the grounds of the two systems together. :roll_eyes:

Yeah, I'm still learning about this electrical/circuit design stuff. That is definitely an issue I overlooked, and thank you (and sterretje) for pointing it out.

You have not really specified the power requirements to the electromagnet. The article describes 5V to 12 V. Which is it? What do you want it to actually do?

If 5 V is sufficient, then a common USB “phone charger” with a current rating adequate for the total of devices you wish to use is a practical approach, generally relatively cheap. You need to split out the USB connector to the 5 V and ground wires, either by finding a USB “A” plug you can wire or by getting a cheap USB cable and splitting out the wires. The advantage of the former is that many USB cables use ridiculously fine wire which may introduce a voltage drop.

This power supply can be connected to the “5V” and ground pins. You could plug it into the USB connector on the UNO but that has a current limit of 500 mA (which is at least, considerably more than the on-board regulator can handle powered from the “barrel jack” or “Vin”).

Post a photo of your breadboard because we can't see it.

If the electromagnet is any use except as a toy then the mounting is too weak.

For using an Arduino to control devices that take a bit more current than the 30mA or so the Arduino can provide, see this page on my site, especially #3