How to handle Voltage Spikes??

Hello everyone, Im doing a project in which I have an Arduino UNO with a GPRS Shield that also powers an Arduino Micro connected to a XBee. Both arduinos communicate through I2C.

The Arduino UNO will be powered by a generator of AC 220v, the connection between both will be by a transfomer that puts out DC 7.5v and 500mA.

The problem is that Ive been told that many electrical devices will be plugged and unplugged from said generator causing Voltage Spikes that most likely fry my Arduinos.

I dont know much about electronics, thats why Im reaching out for a solution.

A friend advice me to buy a power bank that puts out DC 5v 1A between the transfomer and the Arduino, thus having a stable Voltage input. As it is already 5v I have to bypass the regulator and connect it straight to the 5v pin.
Would this work?

Also I was hoping if you could give me any other advice.

Thanks in advance for your time!!

Leo

The Arduino's 5V regulator should provide sufficient protection. The 7.5V supply's capacitors will provide some additional protection, and if the 7.5V is regulated that's another layer of protection.

If the generator is particularly bad, look-up "crowbar protection circuit". It normally uses a Zener and a fuse.

leogar07:
Hello everyone, Im doing a project in which I have an Arduino UNO with a GPRS Shield that also powers an Arduino Micro connected to a XBee. Both arduinos communicate through I2C.

The Arduino UNO will be powered by a generator of AC 220v, the connection between both will be by a transfomer that puts out DC 7.5v and 500mA.

The problem is that Ive been told that many electrical devices will be plugged and unplugged from said generator causing Voltage Spikes that most likely fry my Arduinos.

I dont know much about electronics, thats why Im reaching out for a solution.

A friend advice me to buy a power bank that puts out DC 5v 1A between the transfomer and the Arduino, thus having a stable Voltage input. As it is already 5v I have to bypass the regulator and connect it straight to the 5v pin.
Would this work?

Also I was hoping if you could give me any other advice.

Thanks in advance for your time!!

Leo

Your DC power supply has internal capacitors. You will find that if you unplug the power supply while the Arduino is running, the Arduino will stay powered for a second or so due to the charge in the capacitors.

Therefore, momentary power fluctuations in the AC line (MUCH shorter duration than the discharge time of the power supply) will have no effect at all. The power supply will "absorb" any spikes.

Can you explain this better:

The Arduino UNO will be powered by a generator of AC 220v, the connection between both will be by a transfomer that puts out DC 7.5v and 500mA.

transformers put out AC only - you are talking about some sort of mains input power supply - please
give full details of this. In particular if its cheap and shoddy or not a regulated supply it will probably not be good enough by itself.

Hello it's an Adaptor, something like this:

The one I have doesn't have a switch for polarity.

No doubt, there'll be several sources of EMI you may need to contend with ... conductive and emissive (radiated).

May need to use an EMI/RF shielded enclosure:
http://www.iaasr.com/product/arduino-project-enclosure/
http://www.hammondmfg.com/pdf/EMI_RFI%20Shielding%20Info.pdf