Stumbled across a great intro to prototyping thanks to an article at Makezine, about billionaire Dan Gelbart.  He has a cool set of tools in his basement, and has great instructions for how to build stuff. Check out the YouTube intro and the YouTube Channel. Lessons I liked a lot were on forming plastic molds, and on building…

After I completed the prototype of the bag movement alarm I spent some time turning it into something that is more of a usable product.  I designed a layout to fit onto a protoboard PCB that I got with a small project case I purchased, and then soldered it up and stuck it in the project…

After figuring out the modified power circuit and the battery power monitor circuit, I could finally finish the prototype of the bag movement alarm.  I also added the same power switch circuit for the speaker, which allowed me to use a much better speaker (when I had tried it before with the old power circuit, it beeped…

For the bag movement alarm project, I wanted to be able to monitor the battery level so I can warn the user when they need to change the battery.  A simple way to do this is just to monitor the voltage of the battery, as batteries have a pretty well articulate discharge curve:  with more…

When I integrated the TrinketPro into the bag movement alarm prototype project, the power circuit did not work.  So I needed to redesign the power circuit. I had posted a question about this in the Arduino.cc forum, where forum user dlloyd had helpfully pointed me to an excellent explanation of using MOSFETs as power switches.…

Now that I have the TrinketPro working fine, and have the sketch and prototyped circuit for the bag movement alarm project using an Uno, I wanted to replace the Uno with the TrinketPro. There were a few small changes, as there are two pins on the TrinketPro that are not available:  #2 and #7.  Since…

As part of the hackaday.io Everyday Carry contest that I am (in part) building the bag movement alarm for, I need to utilize a Trinket Pro.  Which is fine, because the product itself is a pretty affordable ~$10, and it packs pretty much to same punch as an Arduino Uno. I ordered one from the…