ATTiny 85 Blink

I just remembered today that I had another Atmel chip that I had sitting around. I originally purchased it to program with the Arduino, which failed. I've been working through the AVR book some more. Recently did some analog stuff however I have a lot of time in between working on it so I forget a lot of what I had previously done. Takes a lot more time to work through things but it is starting to get engrained. The ATTiny85 gets programmed using the same hardware/processes, only has less memory and fewer pins. I programmed it to do a simple blink program just to see if I was successful. Turned out I was, I'm starting to think how I could incorporate this into a project eventually.

Starting with AVR Programming and ATMega Chips

I really enjoy microcontrollers but wanted to understand them in more detail. I saw on O'Reilly media they were having a book sale and noticed one specific to AVR programming. It essentially is a book of programming the chip series that is used on the Arduino and many more. The book is called Make: AVR Programming and I happened to get it 50% off. It takes you through three levels including beginner, intermediate and expert. It doesn't take much to get started. I purchased a few components I did not have on hand and the biggest purchase is an AVR programmer. I bought the AVRISP mkII from Digikey (I think it is now discontinued?). There are others that will work as well. I've started to walk through the book and worked on some basics. Everything is coded in C and the book walks you through on installing all the necessary programs as well. The image to the left is just an example of controlling multiple LED's. I altered the code several times and created several different patterns. Most recently I had the chip hooked up to the computer using Serial-USB communication. Everything I've done thus far has been outputs. The next chapter is inputs so the famous push button example will be up next. Here is a video of one of the patterns I created.

AVR LED PATTERN

Bluetooth Speakers are Complete

I finished my bluetooth speakers that hook up to some old computer speakers. Streaming music from my phone or computer from anywhere in my home. It is not as loud but I could always incorporate an additional amplifier into the circuit. Before I packaged it up, I had everything completed on a perfboard and ensured everything was working. It was not powering at first but it was because I forgot to Ground the board :-/...after that everything worked great.

I packaged it up in a small project box with a 3.5 mm audio jack and it is powered from a 3.3V wall adapter which supplies plenty of current for this project. The two LED's are status LED's to see when someone is connected. Fun and pretty simple project putting some old speakers to use.

Bluetooth Speaker System

We had some old computer speakers sitting around that we utilize in the living room for our ipod or computer. Since I'm a lazy bum I got sick of standing up and "thumbs downing" songs on Pandora or changing songs when we are at the table or entertaining so I went the route of making those suckers bluetooth where we can stream through our phone or computers from anywhere in out place.

I got the bluetooth module from Sparkfun and it has a lot of great documentation on it in regards to getting started. I bought the RN-52 breakout board for convenience but you could go cheaper just buying the module. The speakers I have are 2 speakers and a subwoofer so I cut the audio jack off to see what wires I had. Turnout I had the left speaker, right speaker and a common ground among them. These speakers are externally powered so the signal is already amplified. In the case you would be using headphones or low powered speakers there would be no need to amplify the signal.

Prototype of Bluetooth Speakers

I intend on packaging everything on a protoboard and in a project box. I'm going to power it from a 3.3v wall adapter and add an audio jack if I ever change speakers in the future I won't have to hardwire anything. Functionality wise it works great!

Wheatstone Bridge Hydrometer

So I was not making the wheatstone bridge for my health. My intent was to build a hydrometer for home brewing. There are multiple ways of doing this but I wanted to play around with the strain gages. The principle being the buoyancy of a ping pong ball bolted at the end of a beam would vary as a function of a fluids density or Specific Gravity which is the typical measurement when home brewing.

This was my crude build and attempt at utilizing it as such but was not overall pleased with the results, fun idea. I had a few other ideas for making a hydrometer but ditched them because of cost and complexity to replace a simple glass tube.