The preamplifier and microcontroller board for my blaster. I did this board about two months ago and now I remembered to upload a photo here.
At the moment it only functions as a preamplifier in the temporary miniblaster but in the final blaster the microcontroller part will handle some visualization, battery voltage measuring and some other stuff.
The solder kinda looks messy, but every random looking solder spot is a via between the top and bottom side of the board to connect the ground layers together. Also the area of the operation amplifier looks messy but there are a bunch of SMD resistors and caps around it but they are hard to see from the photo.
Left photo: on the top of the board is the 5V voltage regulator, on the left side there is an Atmel ATmega8L and on the right a random dual operation amplifier to amplify the input signal with two different adjustable gains. The other line goes to the power amplifier and the other goes to an ADC input of the microcontroller so I can sample the signal and then use that data to do some visualizations.
Right photo: left corner of the board has breakout pins from the AVR, on the bottom is the 7-12V input and next to it the signal input. Close to the power amp board are two variable resistors to adjust the gain of the two lines and on the top is the preamplified output that is connected to the input of the power amp. On the center of the board are the pins for a volume adjust potentiometer.