Sounds like you may have a power issue :
Red power LED is blinking
A blinking red power LED indicates problems
with the power supply. On model A and B, it is hard-wired to the 3.3V
power supply rail. If it is blinking, as one user has reported it
means the 5V power supply is dropping out. Use a different power
On model B+ (...
it probably is a power supply problem.
The allowed voltage range is the normal one (for 5V logic) 5.0V ±5%
so its a the range between 4.75V and 5.25V.
Note that the lower limit of 4.75V is more a matter of many USB devices not working below that value than it is that the PI itself is that sensitive, especially as much of it (including the ethernet/hub chip, ...
The red LED is the power indicator, it should be on whenever you have your pi plugged in. The green LED is the sd card access indicator; it goes on when the pi is accessing the sd card (which is like its hard drive). When you plug the pi in, the red light should turn on and then the green light should turn on. After that, the green light will flicker and ...
I use my Raspberry Pi to control my grow lights using a power relay
This is a great way to control line voltage with a Pi and lets you do all sorts of fun stuff on your pi. for example, I use the Pi for timing the daily light cycles.
I do discourage designing your own power line relay. If you make a mistake, you risk severe electrical shock to yourself and ...
The RPI 3 requires 5 volts to operate. This is normally supply using the RPI 3's micro USB port. As the RPI 3 has the ability to run faster on multiple processor cores, it is stated here to get a power supply equal to or lager than 2.5 amps.
The GPIO pins of the RPI 3 do not supply enough current / voltage to drive most common relays directly. You will ...