Final Project-Weeks 17 through 19

Applications and Implications (assignment)

What is the Final Project?

• Make a wireless moisture sensor that turns on a sprinkler valve.

Who's done what beforehand?

• Spark fun has a moisture sensor and watering project. Also, other Arduino projects exist.
• None of these projects are wireless. I was unaware of these projects when I proposed a final project. However, I still believe that I can make a meaningful contribution and will try to make as many parts from scratch as possible.

What materials and components will be required?

• I will make two boards and purchase a solenoid valve. The prices below will be components for one system, but I buy many additional parts for prototyping.

  Supplier	Quantity	Part number	Description	Price	Cost
  http://www.digikey.com/	2	ATMEGA328P-AU-ND	Micro-controller	$3.58	$7.16
  	1	S1133E-36-ND	Connection header	$5.56	$5.56
  	4	609-4958-ND	2X2 Socket connector	$0.73	$2.92
  	4	609-3569-ND	2X4 Socket connector	$1.39	$5.56
  	1	LM3480IM3-5.0/NOPBCT-ND	5.0V 0.1A Voltage regulator	$0.92	$0.92
  	2	LM3480IM3-3.3/NOPBCT-ND	3.3V 0.1A Voltage regulator	$0.92	$1.84
  	2	311-1161-1-ND	100pF SMD 1206 Capacitor	$0.18	$0.36
  	1	497-5559-1-ND	Diode SCHOTTKY 100V 150MA	$0.34	$0.34
  	1	609-4463-1-ND	2X2 header	$0.99	$0.99
  	1	CP1-023PJCT-ND	CONN PWR JACK DC 0.65X2.75MM SMD	$1.39	$1.39
  	2	609-3487-1-ND	2X3 header	$0.84	$1.68
  	1	311-1.00KFRCT-ND	1 kohm resistor	$0.10	$0.10
  	1	311-0.0ERCT-ND	0 ohm resistor	$0.10	$0.10
  	1	1568-1360-ND	Moisture Sensor	$4.95	$4.95
  http://www.amazon.com/	1	2pcs nRF24L01 module	2.4GHz Wireless Transceiver	$6.45	$6.45
  	1	39	Uxcell 2 Pcs 4 x AA 6V Battery Holder	$3.75	$3.75
  	1	GD-001	Etekcity 12V Power Adapter	$4.89	$4.89
  	1		HOSL DC 12V 1/4 Inch Electric Solenoid Valve	$9.99	$9.99

   

What is the schedule?

1. Make an output board that turns on power.
2. Make an input board with a humidity sensor.
3. Connect them wirelessly with two nRF24L01 modules.
4. Make an enclosure for the device.
5. Decorate it with a vinyl sticker.

Step one: Make an output board that turns on power.

RxBoard version 0.1

• Designed an output board in Eagle (RxBoard version 0.1)
• (Final versions of Eagle files are linked below)

• Cut and stuffed board

• Inserted wireless module into header

• Checked all connections several times, but wireless module did not transmit.
• Connected module via wires to header and it worked. (video)
• The connections are all good, therefore I assume the problem is crosstalk or local interference.
• This board turned on the stepper motor board with no problems, but would not allow the solenoid to turn off. When connected, the solenoid was immediately powered and would not power off.

I had numerous other boards that I produced that failed due to milling problems, missing wire traces, and poor design.

• I ultimately setup a bread board and made a switch using a Darlington transistor, a base resistor, and a diode between the solenoid leads.

RxBoard version 0.4

• Using this switching system and substituting a N-MOSFET for the Darlington transistor I made a working board.
• WifiWaterRx.sch and WifiWaterRx.brd

• Milled the board using a Roland MDX 20 mill and stuffed it.

• Programmed the board using the Arduino IDE under Linux.
• Receiver code

Step two: Make an input board with a humidity sensor.

TxBoard version 0.1

• The transmitter board was much easier.
• The moisture sensor already had a resistor for voltage devision, so connection to the ADC and ground was all that was needed.
• In future designs, I will make the sensor with a potentiometer to tune the voltage.
• Designed the schematic in Eagle.
• WifiWaterTx2.sch and WifiWaterTx2.brd

• Milled the board using a Roland MDX 20 mill and stuffed it.

• Programmed the board using the Arduino IDE under Linux.
• Transmitter code

Step three: Connect them wirelessly with two nRF24L01 modules.

• Video of working wireless system

Step four: Make an enclosure for the device.

• Designed an enclosure for both boards in Fusion 360

• RxBottom.stl, RxTop.stl, TxBottom.stl, and TxTop.stl
• Printed them with a Printrbot 3D printer

Step five: Decorate it with a vinyl sticker.

• Used a Roland Vinyl cutter to cut out a decorative sticker.
• Cloud.svg

• Presentation Video