Update on Digital Audio Siggen

I have made what I hope will be the last update to the Digital Audio Siggen. This is to use an LM386 as the output amplifier. I bought an amazing kit for £1.56 on eBay, a complete amplifier with gain control!!! So the schematic is now this:



If I decide to build this, I may do a PCB. This is the hard wired prototype.



The output is up to a little above 10dBV up to 100kHz - pretty good for the LM386!

UPDATE

Later I found that 12V was too much for the LM386 I had an it blew up - seems you need a special version fo ruse at 12V and above. So I have removed the amplifier for now.

Code update here

Sythesised Audio Oscillator

While many struggle to build audio signal generators using phase shift networks, voltage and gain stabilisers and bunches of op-amps, there is another solution. Digital synthesis.

AD9833

The AD9833 is an IC designed for generating Sine, Triangle or Square waves from 0Hz up to +10MHz. It is simple to use with an Arduino to build a variable frequency sine wave generator. Combined with a Rotary Encoder and an OLED display an accurate audio generator can be made for about 20€!

Here's the circuit.


And here's the mockup



Code here.