I would like to build a greenhouse terrarium project using an LCD , DHT11 for humidity , light sensor to measure sunlight as opposed to household light if possible, temperature sensor for terrarium and one for soil, soil moisture sensor and build two sensors for two terrariums with either a switch to turn on each component sensor lead to each terrarium unless I can have the readings of each of them on one lcd all using one uno Arduino. Also a buzzer or LCD indicator for when the soil is too dry or soggy. I am uncertain as to which parts to get exactly. My choices are based on what I have seen online. I’d like to eventually set it up as a weather station at a later date. My arduino skill are very limited to what I learned in the Arduino Basics Kit. Any help would be appreciated with the build, coding, and suggested parts.
Can you explain what you mean by this ?
Is the sensor to be placed in a window or outdoors, separate from the terrariums ?light sensor to measure sunlight as opposed to household light if possible
Also …
Do you mean 2 moisture sensors or 2 complete sets of sensors ?soil moisture sensor and build two sensors for two terrariums
Your project is fairly easy, it’s just a matter of getting the “best” Arduino to handle all the sensors plus LCD. And on that note … do you have an idea of what LCD you want ? What data do you wish to be displayed on it ? I assume it’ll be indoors and so doesn’t have to be sunlight readable.
Probably the biggest question is what to use for a soil moisture sensor. There are ones you can buy but I’ve also seen articles on DIY ones.
Thanks for the response. By different light sensors I was referring to the light spectrum (warm light vs cool light). The warm light is more at desirable for flowers while the other for growth. But after much thought, I figure a berry sensative photo senso that would do that would be costly. I have two terrariums beside one another and instead of buying another arduino, I wanted to build two sensors using the one arduino. The LCD I would use would be the one that came included in the starter kit–unless there is something nicer. I’m thinking the LED output I would like to see is soil temp and moisture, air temp and humidity, light detection as mentioned, and an alarm (either led or buzzer) for when either of those variables are out of range. And if all goes well, I’d like to hook up a weather station few months down the road.
Let’s talk about sensors …
For a light sensor, the simplest would be this …
https://www.sparkfun.com/products/9088
… but all you’ll get is the intensity of the lighting. This …
https://www.sparkfun.com/products/12829
… can give you measurements of the R, G and B wavebands and so allow you some ability to differentiate one light source from another. The first sensor would require an analog input pin (2 pins for 2 terrariums) while the other sensor requires the use of 2 digital pins for the I2C communication bus it uses. Generally multiple I2C devices can all use the same 2 pins so long as each device has a unique ID number. Alas I don’t see a way to change the ID so you’re limited to 1 of these devices for the 2 terrariums (unless you want to go to additional effort).
You haven’t said what moisture sensor(s) you want to use and so I’ll assume it’s an analog output. Do you want 1 per terrarium ? You haven’t said but I’ll assume so and that’s 2 more analog pins needed.
I’m not sure what Arduino Kit you have (a link is always nice) but most come with this as a temp sensor, so let’s keep it.
https://www.sparkfun.com/products/10988
And for 2 terrariums, that’s 2 (soil) more analog pins.
The DHT11 does both temp and humidity and outputs those on a single digital pin. So that’s 2 more digital pins for 2 terrariums.
And then you have the LCD, which may use 2 to 6 digital pins depending on what type it is (link ?).
Lastly you have 1 or 2 digital pins needed for a audio (buzzer) and optical (LED) warnings.
So that’s 4 - 6 analog inputs and perhaps 12 digital pins (one light sensor). Just do-able w/an Uno. But no room left over for additional “stuff”, like a weather station. Then again perhaps I have duplicated too many sensors ??
ps - the I2C light sensors (and others like it) are 3.3V parts and so either require a 3.3V Arduino or a logic level translator to “talk” to 5V Arduinos.
https://www.sparkfun.com/products/11955