# Voltage Inverter: Arduino to 250Vrms AC @ 25-200Hz

Hello!

I am new to Arduino (besides working through Banzi's Getting Started with Arduino) and have the following design need and appreciate any pointers / feedback.

I am working with a type of Smart Glass that needs the following input to change between states:

230-280Vrms square wave AC voltage at 25-200Hz.

Any help is greatly appreciated.

Thanks, Bt

Do you need to change the Hz? Rectify the 240V to 2 parts -240 and +240 (assuming you need both parts) with diode rectifier(s) (2 needed to get both polarity) http://en.wikipedia.org/wiki/Rectifier switch the rectified dc with a opto isolated fet on 2 pins turning -+-+-+ with the pins at the appropriate frequency

David

Please clarify exactly what changes between states: Does the voltage (230V vs. 280V) change between states? Does the frequency (25Hz vs. 200Hz) change between states? Or is no voltage at all vs. ~250VAC the factor that changes between states?

I suspect that when you apply NOTHING, the glass is on one state, and the glass changes state when you apply a large AC voltage

Your assumption is correct. The glass is in one state when No Voltage is applied and another state when a voltage between 230-280V and at 25-200Hz is applied.

I live in the U.S. (110V 60Hz)

Thanks for info. I'll start looking into optical-coupled solid-state relays.

You should be able to find a DC to AC inverter that will take 12 or 24 volts DC and produce 230VAC - search inverter in google,

You could use something as simple as an optical-coupled solid-state relay to switch the mains power on and off. A solid state relay like this can be connected directly to an Arduino digital output pin.

I've been looking around a bit online and have a quick question.

Will any optical-coupled solid-state relays provide a square wave?

I live in the U.S. (110V 60Hz)

Thanks for info. I'll start looking into optical-coupled solid-state relays.

Well most U.S. homes have 230vac single phase supplied to their homes. It's used for the higher power appliances such as cloths dryers and ovens. You haven't stated a current requirement for the glass phase change, but I assume it's very low, almost an electrostatic requirement? Anyway a small 230 to 230 isolation transformer with a small fixed fuse and a solid-state relay should meet your power input needs. You may have to have a fixed permanent load of say a 230vac low wattage lamp or maybe just a fixed resistor load as solid-state relays require a minimum current draw from the load that your glass thingy may not possess. Not sure how to advice you of how to turn the 230vac sine wave into a square wave, it that's a true requirement, I'll leave that to others as I'm not sure I would attempt to build a 230v comparator op-amp. ;)

Anyway an Arduino can directly drive a solid state relay, so control is pretty simple. Just be very very careful with 230ac stuff. If you don't have experiance working with high voltages you might try and get local experiance people to help or work with you.

Lefty

The power required is 1 watt (1W).

Sorry for not including earlier.

Looking at 1 Watt required for the demo piece and a desired voltage of 250 Volts the amps is 0.004 amps. I believe that is right (Amps = [Watts / Voltage] = [1 w / 250 v] = 0.004 amps).

Thanks for the help Richard.

I went ahead and ordered the 229E230 from Mouser earlier today.

Bt

I received the 229E230 in the mail today.

I am not sure how to proceed and after reading a few threads over concerns on AC power I want to make sure I get it right.

Here are the circuit schematics that were included in my package.

The transformer is listed as being a PCB mount. Can I utilize a solderless breadboard initially for design purposes?

Design Objective

To be able to send ON/OFF command via Arduino

Thanks, Bt