[McHUG] Arduino Shields

[Rich Mitchell]

 McHUGgers,

The long weekend of snow with no power outage really helped my Arduino shield project.  
Once the parts got here (and turn around from both Modern Device and from NKC was very quick) I first built a protoboard shield for the Deumilenova Arduino to make it useful.  I used the NKC proto board kit and a small breadboard that I liberated from an old PICAXE board.  This plugged on top of the Arduino so I didn't have to rubber band it to a large breadboard like you sometimes see.

The next project was making a Bare Bones Board shield compatible.  I got a BBB and was going to try to populate a shield board directly with the parts.  One of the problems was how to provide external power to the board and still keep the profile low enough for shield compatibility.  After studying the new RBBB (which is not as really bare bones as the older RBBBs because it has an external regulated power supply) I realized that if you built the RBBB as thin as possible (solder the 328 directly to the board and bend over tall components) it would fit beautifully onto a shield board with the external regulated power supply extended over the end where it would not interfere with shields.  I was able to provide all the right connections to the shield connectors with the exception of the 3v pin.  I did not wire up the ICSP pins, though that could easily be done.  I also provided a 6 pin bent male connector so you could program and serially monitor it using the FTDI TTL-232R cable.

Now one of the things the RBBB shield board did not have was the ability to connect it to a computer using a regular USB cable, like the Arduino can.  So the first shield I built for the RBBB was one that held the BUB board, which uses the same chip as the Arduino for USB connection.  Because the BUB board only took up half the shield I provided a serial LCD connection for LCDs piggybacking the LCD 117 Board.  This connection is just 5v, ground and a data pin.  I made the data pin selectable from any of the digital shield pins so that it would be flexible for what an application required.  Not only did this shield provide direct USB connection to the programming computer but it also had a 3v. output as well as 5v.  Both of these are switchable in case you want to run with an external power supply from either the RBBB shield or an Arduino.

I then could plug the breadboard shield right on top of that and start playing.  I set up a simple 434 MHz receiver on that breadboard and a 434 MHz transmitter on my old BBB breadboard setup.  I used the VirtualWire library and got the transmitter at one end of my house talking to the receiver at the other end.  I don't think that VirtualWire is compatible with the SoftwareSerial setup that Anderson uses to do the serial LCD.  As soon as I added the VirtualWire setup code, the LCD would print garbage.  Maybe they are both using timer one.  So I ended up using the serial monitor through the BUB board shield - which worked perfectly.

Before we make a shield of the receiver we need to find out what we would need to also pick up PICetSat Morse code transmissions.  If we decide that VirtualWire is a good way to go for digital comms, and if there is indeed conflict with the serial LCD software, then a four wire LCD connection would be a good thing to add to the receiver shield.

I was able to show the shield work I had done to Dave in the parking lot of yesterdays non-meeting.  We did not start up the NetBook to see the shields in action.

With the new storm already starting, if it leaves the power on, maybe I can do more shield work.  and when the storm clears out, maybe we can set up a Meet to Eat and chat about this stuff.

73,
Rich, N3III

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