I am using an Arduino Uno with a 4 relay module (found here) and an Adafruit CC3000 WiFi breakout board. However, once I connect the power source, the board just constantly cycles on and off, e.g. about 1 second per cycle. Could this have to do with too much current being drawn? Or that the current output of the digital pins isn't enough for all of the relay inputs? I'm new with this, but I am sure all of the pins are appropriately connected.
EDIT: If I use the USB connector (5V 1A) instead of the external power supply, I can connect 1 or 2 of the relays without problem, but any more causes the wifi to disconnect and become unresponsive. However, I must connect the relays AFTER the wifi has already connected to the network, otherwise the wifi will never connect. Also, if I toggle the relays a few times, the wifi becomes unresponsive. I assume this is maybe a current issue? Any ideas? Thanks!
Yes, sounds like a current draw problem.
Can you use a lower voltage current source? Like 7.5V?
4x 80mA for the relays.
350mA peak current for the WiFi board.
~55mA for the Arduino.
Could be 725mA total peak draw.
As CrossRoads said, maybe just ok with 7.5volt on the DC jack.
More than that will overheat and shut down the regulator.
Find another way of powering the relay board.
Thanks for all the replies! I can get a new power source, but would prefer to use the one I currently have. I'm no expert with wiring or EE, but is there any way I could use some resistors to keep using my current power source? Or am I just totally wrong with that thought? Also, why would the regulator overheat? I thought it could handle at least 12V. Would I maybe need to heatsink it? Thanks!
With 12V source, 5Vout, that is 7V that must be dissipated by the regulator. Voltage x current = power in watts.
7V x .725A = 5W. That is a lot of power for a little regulator with minimal heatsinking. It will get hot and go into thermal shutdown, when it cools off, starts regulating again, overheats, shutsdown, etc.
With 7.5V source, only 2.5V is dissipated. 2.5V x .725A = 1.8W, may have a chance at keeping cool enough.
If you want to use a resistor between the source and the barrel jack, be sure it's a high power wattage rated part.
5V x .725A = 3.6W, so get a 5W rated part at least.
Thanks so much for the help!
Where did you get the uno? Arduino.cc has good quality regulators. Never seen one shut down with 12V supply under relatively high load. Arduino.org has been selling shit quality regulator since the later part of 2014. 12V no extra hardware overloads the regulator in minutes. Clone arduinos are usually alright.
I couldn't drive for MAX7219 from 12V, regulator went into thermal shutdown.
Would run for a bit, heat up, shut down for a few seconds, restart, run for a bit, etc.
Runs okay from 9V tho.
As always, you should absolutely never be attempting to power one of these relay boards from the Arduino's internal 5 V supply.
You remove the JD-VCC to Vcc jumper. The Arduino output pins connect to the respective inputs, and "Vcc" connects to the Arduino Vcc.
"JD-Vcc" and ground connect completely separately (that is, not through the Arduino connections) to a relay power supply which can be another 5 V regulator from your 12 V supply.