Mega voltage question

So I have a configuration consisting of 3 8-relay boards, with a total of 24 relays. I have a light switch sketch that turns a switch on and off from an Android app.

I can turn on 8 relays at once on 1 relay board, however, when I start turning on relay 9, 10 and so forth on relay board 2, it seems I run out of juice - all the relays turn off without me turning them off. I did a forum search to find a solution but nothing specific to my scenario. I would like to be able to power on all 24 relays at once and assuming I would need an external PS. What can I do to rectify my problem?

I purchased this hoping it would resolve the issue, but the problem still exists when the Arduino is powered with this PS.

http://www.amazon.com/gp/product/B00BWA48AA/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

How about some info on the relay board?

650ma of current is not much... how much current does each relay consume? (Use a multimeter set to ohms and measure)

Sounds like the regulator is dropping out.

you can usually power the relays with external power, then just send an "signal" from the Arduino...

CrossRoads:
How about some info on the relay board?

Sorry about that, here you go! This is what I purchased, and attached is a schematic.

Qdeathstar: you can usually power the relays with external power, then just send an "signal" from the Arduino...

True, is there a recommended board PS for the relays I posted? The arduino will still need to send 5 v to the relay switch right? All 24 on at the same time.

Datasheet here http://www.datasheet-pdf.com/datasheet/Songle/720556/SRD-05VDC-SL-C.pdf.html says the coils need 70mA each. 8 x 70 = 560mA. 3 boards = 1680mA. You need a bigger 5V supply for the relay boards to connect to JD-VCC. Do not install the jumper that connects VCC to JDVCC. Connect board's GND to Arduino GND. http://www.dipmicro.com/store/DCA-0520

CrossRoads:
You need a bigger 5V supply for the relay boards to connect to JD-VCC.

Is there one that you recommend?

CrossRoads:
Do not install the jumper that connects VCC to JDVCC.

Ok I just want to make sure I understood correctly, attached is a picture of my board, are you saying to remove the VCC and Ground which I currently have connected to my Arduino in the IN1-8 row and use the JD-VCC and ground where the jumper is to power the board from an external source?

CrossRoads:
Connect board’s GND to Arduino GND.
Switching DC Wall Power Adapter 5V / 2A - dipmicro electronics

Will this resolve my entire issue? Or will I still need the external PS for the relays.

Connect GND from all cards next to In1-2-3-4...to Arduino Gnd. Connect dipmicro 5V/2A supply to GND/JD-VCC. Remove the yellow (orange) jumper.

External supply is needed. The relay coils need more current than you can get from the Arduino 5V supply.

CrossRoads: Connect GND from all cards next to In1-2-3-4...to Arduino Gnd. Connect dipmicro 5V/2A supply to GND/JD-VCC. Remove the yellow (orange) jumper.

External supply is needed. The relay coils need more current than you can get from the Arduino 5V supply.

The link you gave me shows a 2.1mm plug, how am I wiring that up to the relay boards to JD-VCC?

Plug into something like this, split out to three boards. http://www.pololu.com/product/2449

CrossRoads: Plug into something like this, split out to three boards. http://www.pololu.com/product/2449

Thank you for all your help CrossRoads. I wanted to recap and make sure I got everything:

  • Remove jumper and connect external PS to JD-VCC. Nothing connected to GND and VCC. (or do I connect the GND to the PS?)

  • Leave GND on the row of pins with IN1-8 connected to the Arduino.

  • The PS I purchased from Amazon is that good enough to power the Arduino?

I just want to confirm I'm doing it right before I burn my house down XD

Connect PS to JD-VCC and GND. Leave GND connected to Arduino - use a meter and make sure the two GNDs on the relay card are connected. Amazon supply looks to be 9VDC, 650mA, good for Arduino use.