Si5351 breakout board

Jason/NT7S launched the crowdfunding campaign for his version of an Si5351 breakout board last night, and already this morning it's at over 150%. The stretch goal at $1 500 involves spending some more time on the software library to make the board easier to use.

It's a neat little oscillator chip that seems to provide a lot of capabilities for not a lot of money. He's been documenting his investigations on the chip at his blog for the past year now, including building a couple of receivers and transceivers around the Si5351.

The Si5351A is quite a capable IC at a very modest price. It is a PLL clock generator with three independent outputs which can each generate a separate signal from 8 kHz to 160 MHz. A 25 or 27 MHz reference oscillator is used for the two internal PLLs (the Etherkit breakout board uses a 25 MHz reference oscillator), which allows the user to choose the amount of frequency stability and accuracy required. 

Go check out the Si5351 breakout board campaign on Indiegogo, and pick one up if it's something you'll find useful in an upcoming project.

Arduino thermometer

Started with my first big Arduino project using one of the Sparkfun Redboards and my new *duino work station.

The Adafruit RGB LCD shield and TMP36 temperature sensor were pretty easy to wire up to the Redboard. The LCD shield communicates using the I2C pins, so it just need those to connections plus 5V power and ground from the Redboard. The TMP36 was just as easy to wire using 3.3V power and ground from the Redboard and connection to one of the Redboard analog inputs.

FreezerThermometer.jpg(There was no Fritzing part for the LCD shield, so I just used an LCD display part instead)

A few hours of writing some code and fiddling around got me a working thermometer.


Thanks to the Adafruit RGB LCD library, the sketch for what I've done so far is pretty simple. Pressing the Select button on the shield makes the LCD turn on and display the current temperature as well as the range of temperatures measured since it was turned on. The temperature is displayed for 30 seconds, then the LCD and backlight are turned off. Pressing the Select button again makes it display the temperature again.

The next step will be to add some additional functions accessed via a menu. I'll add a speaker or buzzer and have it alarm above a certain temperature. Once I have this prototype working nicely, I'll repackage it and turn it into a thermometer to monitor the temperature in our freezer. I'll have to figure out how to attach the thermometer to the power and analog pins, because the LCD shield doesn't break them out. Shouldn't be too hard to work out.

Inside a cassette adapter

Found one of these rummaging around in the car the other day.


If you have no idea what this is or don't get what it's for, ask your parents.

The cassette player in the car kept spitting it out, so I figured I'd open it up to see what was inside.

DSC01868.JPGSurprisingly simple inside and much less than I expected. Just the magnetic read/write head and a single circuit board.

DSC01870.JPGDSC01873.JPGThere are just a couple of capacitors and a couple of resistors (on the other side of the board), so it's a very simple circuit.

DSC01875.JPGThe resistors are pretty big, 820 MΩ, presumably to knock down the input down to something the cassette player can deal with.

*duino work station

Inspired by the Sparkfun Arduino and Breadboard holder, I decided to build my own portable work station to use for building projects with my *duinos.

I cut a 27.7cm x 40.5 cm piece of 6mm thick (1/4") plywood from stuff I had on hand to serve as the base, and started playing around with how I wanted things laid out. I eventually settled on a setup with three breadboards around the *duino board (in this case, a Sparkfun RedBoard) and a little parts bin on the side.


Scrounged up some nylon standoffs and screws to mount the board to the plywood and I ended up with this.


I can switch between the Netduinos and RedBoards pretty easily, and it gives me plenty of breadboard space to work on. The parts bin stays on the board thanks to the magic of Velcro and I used the adhesive backing on the breadboards to stick them to the plywood.

Still have plenty of room on the left side to put other things. Now I'll be able to easily pick up my projects and move them somewhere else to work on. 

My Radio Shack closed :(

My Radio Shack on Folly Road fell victim to the store closings announced by Radio Shack earlier this year. The closing was a surprise, because I had stopped in there a few days ago and there was no indication of anything amiss.

Stopped by there yesterday to pick up something I had been thinking about, and saw the sign saying the store had closed, and some bigger signs giving the location of two other Radio Shack locations. There were a number of people in the store scurrying about taking inventory or something like that.

Now instead of being 5 minutes away, the nearest Radio Shack now is significantly less convenient to get to.

The closing makes me very sad.

BarcampCHS 2014

Another BarampCHS is in the bag. I haven't seen any numbers yet, but attendance seemed lower this year, and there weren't quite as many sessions. The ones that were presented were pretty good though.

Once again, I was wearing my Star Trek bathrobe :)

I pitched my amateur radio session again, and it got put on the schedule in the first time slot. Had a pretty decent turnout of people who didn't have their licenses yet and were actually interested in getting one. I recycled my amateur radio talk from a couple of Barcamps ago and answered a bunch of questions. Tom/AJ4UQ stopped in towards the end and helped out a bit with the questions too. Then throughout the day, I had a few people stopping me to ask about how and where they could get licensed.

Joe/@joel8x got a picture of me giving my presentation

Joe did another great job wrangling Barcampers for the group photo just before lunch.

Having my talk in the first session of the morning meant I could spend the rest of the day attending sessions, and I was able to make it to some pretty good ones. Clay McCauley gave a nice talk on basic automotive maintenance. There was a short informative talk on the Shellshock vulnerability, and the last one I went to was a packed room talk on genetic programming by Ted Tanner.

Once again, another good BarcampCHS year where I learned a few new things.