How to Create a Beer Bottle LED VU Meter

Step 15: Challenges

When I originally made this project I ran into a few challenges and a couple set backs. First off, there were a couple solder bridges and unwanted connections after I assembled the PCB. Those problems were minor and it didn't take long to fix them with the continuity function on my multimeter. Then I realized that I didn't allow enough room on the PCB for a heatsink which goes onto the LM7805. Luckily, there was enough room for it to be installed backwards. The LM7805 gets warm but it doesn't get hot, so I'm lucky that even though the heatsink is installed backwards it still has enough surface area touching the regulator to dissipate that extra heat. If you look at the PCB now I have added enough room for a heatsink on the LM7805 and it can be installed the right way.

Those last two setbacks were quite minor, I found the biggest setback when I noticed that I hooked up the green and yellow LEDs up to the IRL510's the wrong way! That is why my project lacks the functionality to control the lemon and the bottle. Now I just hardwired them in so that they are both completely on all of the time, but that takes a lot of fun out of the project. Once again, I fixed that in the PCB so that anybody who makes this project does have that functionality.

The error is posted in the photos to this step, but it happened because I had the LEDs connected to the source of the IRL510's and then grounded. Now I thought that this would work, but for some reason when I'd supply +5v from the PIC to the gate of the MOSFETs, the MOSFETs wouldn't allow enough current through and the LEDs wouldn't light up. So I got out a breadboard and started trying to figure out why it wouldn't work. Then I connected it up so that the LEDs were connected to the drain of the MOSFETs and voila! When I'd put +5v on the gate of either IRL510, their corresponding LEDs would light up. I should have wired it up this way from the start.