Output Devices

For this week, I began looking at audio amplifiers in anticipation of my final project, a bicycle mounted boombox. I began by making Neil's H-bridge audio amp. This was a pretty simple process, it seems like I'm getting pretty comfortable with the milling and stuffing workflow.

After I changed the makefile to use a ATtiny 44 instead of 45, it seemed to upload the code just fine. However, I realized the output format was different for the H-bridge board I had made than for the simple mosfet amp that the code was written for. I started looking at ways to make a better amp. I did a lot of research, and finally stumbled upon this 70 watt amp, based on the attiny44.

I first tried to adapt this code to my first board(and still may do this). The problem is that I dont have the pins pulled out, so I'd have to solder some very fine connections on the unused pins of the IC. Neil's board also doesn't use the Tiny44's hardware PWM, and I wanted to change the pins for the speaker output to pins that do use PWM. I instead designed a sort of hyrid board that combies the schematic from the hackaday site and parts of Neil's H-bridge board.

Here is my Franken-schematic...

and my layout...

and my traces...

and the finished board.

Of course when I went to load the code, I got this infuriating message

Soooo... it looks like this week is a bust. I want to try again, but I think I will make my own H-Bridge with MOSFETs. I also need to learn more about the audio input signal.