MAIA Gießsystem

(giesssystem@michellemaia.com)

List of materials (prototype 3)

Berlin, 04/2018

To control better the power consumption and avoid short circuit, I've decided to design my own PCB with EasyEDA but now I'm using only the ESP-12 module to control the system.

First I substituted the ESP-01 for the ESP-12 because I can access almost every pin of the ESP8266ex IC. And then I got rid of the ATmega328P microcontroller because the ESP-12 module has a more powerful 32-bit processor embedded. Because of this change, I had to use a multiplexer (CD74HCT4051 IC) connected to the analog input of the ESP-12E module and operational amplifiers (MCP6004 iC) to isolate some pins of this module.

I'm still using the HC-SR04 module (water level sensor), the capacitive soil moisture sensors, the same pump, the same stepper motor and its drive. You can find the main components of my PCB on Table 3.

Component	Price	Electrical Characteristics	Datasheet
	~ € 3.50 Amazon.de Amazon.com	Max. Current at startup: ~ 500 mA Operating Voltage: 3.3 V	ESP8266 SMT MODULE
	€ 0.90 Digi-Key	Current - Supply (Max): 1 mA	IC REG LINEAR 3.3V 1A 8HTSOP-J
	€ 0.90 Digi-Key	Current - Supply (Max): 1 mA	IC REG LINEAR 5V 1A 8HTSOP-J
	€ 0.50 Digi-Key	Current - Collector (Ic) (Max): 500mA	IC PWR RELAY 7NPN 1:1 16SO
	€ 0.41 Digi-Key	Current - Leakage (IS(off))(Max): 400nA	IC MUX/DEMUX 8X1 16SOIC
	€ 0.36 Digi-Key	Current - Supply: 100µA	IC OPAMP GP RRO 1MHZ 14-SOIC
	€ 0.25 Digi-Key	Drain to Source Voltage(Vdss): 30V Current - Continuous Drain(Id)@25°C: 500mA	MOSFET N-CH 30V 500MA SOT-23
	€ 0.12 Digi-Key	Vce Saturation (Max) @ Ib, Ic: 400mV @ 5mA, 50mA	TRANS PNP 40V 0.2A SC75-3
	€ 0.11 Digi-Key	Voltage - Forward (Vf)(Max)@If: 1.1V @ 1A	DIODE GEN PURP 400V 1A SMA
	€ 0.24 Digi-Key	Current Rating: 3A Voltage Rating: 250V	CONN HEADER XH SIDE 5POS 2.5MM
	€ 0.48 Digi-Key	Current Rating: 2.5A Voltage Rating: 24VDC	CONN PWR JACK 2X5.5MM SOLDER
	€ 0.15 Digi-Key	Contact Rating @ Voltage: 0.05A @ 24VDC	SWITCH TACTILE SPST-NO 0.05A 24V
Table 3 - List of materials (prototype 3)

List of materials (prototype 2)

Berlin, 12/2017

My first approach to assemble the system was to use a universal PCB to connect all the modules to the Arduino Nano and use the modules that I had or buy them from Amazon.de. On Table 2 you can find these components, the price (usually I buy five of them because something always goes wrong they become cheaper) and where you can buy them, the electrical characteristics (always essential to know to choose or to design the power supply) and technical information.

Component	Price	Electrical Characteristics	Datasheet
	~ € 1.65 Amazon.de Amazon.com	Operating Voltage: 5 - 12 V Operating Current (5V supply): ~ 300 mA	STEPPER MOTOR
	~ € 2 Amazon.de Amazon.com	Operating Current:15 mA Operating Voltage: 5 V	Ultrasonic Module
	~ € 8 Amazon.de Amazon.com	Operating Current: 400 mA Operating Voltage: 12 V	-
	~ € 1.60 Amazon.de Amazon.com	Operating Current: ~ 20 mA Operating Voltage: 5 V	Relay
	~ € 0.50 Amazon.de Amazon.com	125 V AC 5 Amp	SPDT Switch
	~ € 12 Amazon.de Amazon.com	Average Current: 5 mA Operating Voltage: 3.3 - 5.5 V	Capacitive Sensor
	~ € 3.50 Amazon.de Amazon.com	Max. Current at startup: ~ 500 mA Operating Voltage: 3.3 V	WiFi Module
	~ € 3.50 Amazon.de Amazon.com	Operating Current: 19 mA Operating Voltage: 5 V	Arduino Nano
	~ € 7.99 Amazon.de Amazon.com	Operating Current: 2 A Operating Voltage: 12 V	-
Table 2 - List of materials (prototype 2)

List of materials (prototype 1)

Berlin, 12/2017

On Table 1 you can find the components that I have used on the first prototype (and discarded in the second version). Instead of the stepper motor I have used the servo motor (I've changed that in the second version to get a linear movement). To mesure the soil moisture and the water level I was using resistive sensors (but they don't last one month). Also there wasn't connection with the Internet, so I was saving the data on a MicroSD Card and getting the time value with the RTC module.

Component	Price	Electrical Characteristics	Datasheet
	~ € 2 Amazon.de Amazon.com	Current (5V supply): ~ 500 mA	SERVO MOTOR
	~ € 1.50 Amazon.de Amazon.com	Current (5V supply): 35 mA	Resistive Sensor
	~ € 2.25 Amazon.de Amazon.com	Working voltage: 5V Working Current: 20ma	Resistive Sensor
	~ € 2 Amazon.de Amazon.com	Max. Current: 200 mA Operating Voltage: 5 V	Card Module
	~ € 1.50 Amazon.de Amazon.com	Less than 500nA in Battery-Backup Mode with Oscillator Running and 5V DC supply	RTC Module
Table 1 - List of materials (prototype 1)