Automated growing using Raspberry Pi

[Craigjw]

Hi, I have a mini cab which I've had some success with in the past. I'm now improving the cab design by making it more automated by using some electronics and an old Raspberry Pi model B, which has been kicking around gathering dust for a few years now.

I have none to little experience of the Python programming language, which I will be using to program to sense temperature, humidity and control the lights and fans with, however, I do have experience with other programming languages, so Python shouldn't be too hard for me to pick up.

I have studied a couple of other posts that discuss Raspberry Pi automated grows, here are the links. I am using these as a base for my build.

Automated Raspberry Pi Growing Monitor

Raspberry Pi Automated Growing

I have purchased some equipment to build a control box with, here is a list of what I have:

1x Raspberry Pi model B
micro USB power supply
8gb SD card
Network cable
HDMI cable
USB wireless keyboard/mouse
1x 4 Ralay module
1x Temperature & humidity sensor
Female-Female jumpber cables

Hammond ABS Enclosure 221x150x64
2x C13 IEC Chassis outlets
2x C13 IEC Straight cable sockets
2x C14 IEC Straight Cable plugs
1x C14 IEC Fused and switched Inlet
5x 2.5mm x 5.5mm Male & Female Panel mount socket jacks
1x 3-Pin DIN Panel mount socket & plug connector
5x 4 way Wago push connectors
26 AWG PVC stranded wire 7/0.16mm

[Craigjw]

Here is the equipment set out neatly, for you to get an idea of what I have procured.





I have cut out sections of the encasement to fit the various sockets and plugs



And here's what they will eventually look like

[M_C]

I'll be keeping an eye on this

[Craigjw]

Here's some basic Python that describes how to control the Relay. I'm using the GPIO ports 02, 03, 04 & 17.

import RPi.GPIO as GPIO
from time import sleep
GPIO.setmode(GPIO.BCM)

#set relay pins as output
GPIO.setup(02, GPIO.OUT)
GPIO.setup(03, GPIO.OUT)
GPIO.setup(04, GPIO.OUT)
GPIO.setup(17, GPIO.OUT)

while(True):
#turn all relays ON
GPIO.output(02, GPIO.HIGH)
GPIO.output(03, GPIO.HIGH)
GPIO.output(04, GPIO.HIGH)
GPIO.output(17, GPIO.HIGH)

sleep(5)
#turn all relays OFF
GPIO.output(02, GPIO.LOW)
GPIO.output(03, GPIO.LOW)
GPIO.output(04, GPIO.LOW)
GPIO.output(17, GPIO.LOW)

sleep(5)

[Craigjw]

Here's some basic Python that describes how to monitor the Temperature and Humidity sensor. This was using GPIO port 02.

import sys
import Adafruit_DHT
import time
import json

sensor = Adafruit_DHT.DHT11
pin = 02
while True:
humidity, temperature = Adafruit_DHT.read_retry(sensor, pin)
data = {'humidity':humidity,'tmperature':temperature}
print(humidity,temperature)
print 'Temp: {0:0.1f} C Humidity: {1:0.1f}%'.format(temperature, humidity)
time.sleep(2)

Output is received every five seconds, a sample is shown below where I breathed on the sensor:

Temp: 24 C Humidity: 64%
Temp: 25 C Humidity: 64%
Temp: 28 C Humidity: 76%
Temp: 28 C Humidity: 78%

Not sure if I need the json import at the top, will remove & test this at a later date.

[JamesJoyce]

I am interested in this but have very little knowledge of programming. I just wonder can this system play with fan speeds also?


Stumblin' in the neon groves

[Bulls]

I have 0 idea what are you doing but sounds interesting . I will keep an eye

[Craigjw]

I am interested in this but have very little knowledge of programming. I just wonder can this system play with fan speeds also?

I have looked into this and I don't think it's so easy for 2 reasons; current draw and availability.

If a variable voltage resistance is applied to the circuit, it needs to be able to handle the current draw, if it's not enough, it will melt. ie, the speed controller needs to be properly rated. Perhaps someone can elaborate on this better than I can. When I first created my cab with pc fans, i attached a pc fan controller, however, controlling 6 pc fans caused the controller to melt in under a minute.

I can't find a digitally controlled speed controller with a suitable rating that will handle the current draw, most of the ones available are rated too low or are only manually adjustable.


A circuit using some form of MOSFET maybe the way to achieve this, but I don't know enough about electronics to be able to design/build it and also guarantee it wouldn't melt.

If anyone has electronics knowledge enough to design a circuit that would be suitable, please let me know.

[Craigjw]

I have 0 idea what are you doing but sounds interesting . I will keep an eye

I'm building a box that will control the following:
-When the lights turn on & off, which include an LED & CFL
-When the fans turn on & off
-When it waters the plant
-Monitors the temperature & humidity.

The box will have programming in it to switch on & off the lights depending on the temperature, if it gets too hot, it'll turn off the CFL, if it gets way too hot, it'll turn off the LED also. It will also keep a log of all of the above.

[Bulls]

Seems a bit pointless to me for a small grow..no offense just my thinking.
It is not any different from running your fans and heater though a controller and stick a watering pump with couple of drippera on a timer? Set your controller to max/min on the extraction/intake and the desired temp and humidity and you won't have to worry about switching the lights off?