I started this project so that I could easily dispense a preset amount of water into my brew kettle when brewing beer.  My local brew club has a brew house and currently has hoses attached to the water filtration system.  Instead of waiting to fill up jugs of water this device will allow me to set 6.5 gallons, turn on the water and it will automatically shut off at the preset volume of water.  This lets me get started on other things while the water is dispensing and assures an accurate water level.

Parts include:

Arduino Uno $25 but will be replaced with a $3 ATMega Chip Later
YF-S201 Water Flow Meter $11
LCD Display Panel $5
ECHOTech Solenoid Valve $9


The flow meter is hooked up to the Arduino and there is a basic program uploaded that displays the flow rate and total volume of water that has passed through the flow meter.

Below is a video of the flow meter working.  I had to tweak the program to take measurements every 1/8th of a second.

The flow meter in action.

TODO: Wait for solenoid to arrive.
TODO: Code the reset button, Volume Up and Volume Down buttons.
TODO: Hardwire circuit to breadboard for compact mounting.
TODO: Mount in project box (waterproof).

So I decided to jump in to serial communication.  Why not?  I have a ublox LEA-5H-0-009 GPS Receiver and a GS407 break out board from sparkfun.com. I connected the red (3.3v) and the black (gnd) from the GPS to the netduino.  There is a TXO and RXI pin and a GPIO pin on the GPS break out board (BOB).  I admit, I had to google a lot.. I mean a LOT to figure this one out.  Eventually I found a great article from blog.bobcravens.com with 99.9999% of the solution.

http://alphafn.com/oldpics/2011-08-05 15.35.28

I learned a lot about serial communication from reading Bob’s article.  In summary, what I learned is that I can use D0 and D1 on my netduino as a serial port COM1.  D0 is COM1 IN or RX and D1 is COM1 OUT or TX.  The last piece of the puzzle was the GPIO pin on the GPS.  Clueless me had no idea what to do with the GPIO pin.  After reading his blog, it seems that is used to turn on and off the power.

Here are a few better views of the connections.  Ignore the IC chip and the three axis sensor on the project board.

http://alphafn.com/oldpics/2011-08-05 15.35.38

http://alphafn.com/oldpics/2011-08-05 15.35.28

When I first connected the device I was getting nothing from it because the TX and RX were flipped.  Then, I started getting bytes from the serial port but they were poorly formatted and I could not convert them to UTF.  This caused errors when using the System.Text.UTF8Encoding.UTF8.GetChars(buffer); code.  As it turns out the baud rate needed to be 9600 and I had it at 4800.  After that fix I was set and I was getting NEMA messages.

It does not look like it is picking up a signal yet but that is my next step.  Get the messages decoded and get the device to lock on a few satellites.

Here is the code I used which I got from Bob’s post and tweaked a bit as I was running into issues decoding the bytes because of the baud rate issue.