I make two premises :
This is my first Instructable
- I'm an ignorant Italian who has not studied English at school, and that's why I asked for help to:https://translate.google.it
Start with thank a few people who, through their work, have inspired me and helped me to "play" with Arduino / Genuino
My professor of laboratory "Perito Carli"
Step 1: My Workshop
In my workshop I wanted a watch that in addition to the hours and the date I also wanted to know the ambient conditions
The work can be done easily with Arduino, only serves an RTC, a DHT22 (a bit 'more expensive but more accurate than a DHT11) and BMP180
But we see in detail the necessary material
Step 2: Material
- Arduino or Arduino standalone
- BMP180 - Barometric Pressure/Temperature/Altitude Sensor
- DHT22 - temperature-humidity sensor
- RTC DS1307
- 1 Stripboard
- electric wires
- 3 buttons
- Boxes for four fruits GEWISS
- LCD 20x4 I2c
- 1 Photoresistance
Arduino there is little to say, because of limited space I used an Arduino Standalone
The sensors were purchased by aliexpress, they cost little but put us 40 days to arrive in Italy from China
The buttons are used to adjust the time since the RTC has a margin of error of one minute per month (diagram and sketches taken from arduinoenonsolo)
The Photoresistance to explain later
Step 3: Protocol I2c
The DISPLAY, RTC and BMP180 communicate with Arduino through the I2C protocol and the library Wire.
All three elements must be connected in parallel to the respective SDA and SLC contacts Arduino that correspond to the pins A4 and A5.
To facilitate the work, and not to confuse the contacts I used the wires with the same colors
The RTC module is a "clock" that, by communicating with Arduino, counts the real time (Hours, Minutes, Seconds, Day, Month, and Year).
The RTC is supplied by a buffer battery that, when the power is off, continues to calculate the passage of time.
The BMP180 Module (Barometric Pressure / Temperature / Altitude Sensor) is a high-performance sensor that provides temperature, barometric pressure and altitude.
I used the library SparkFun
Step 4: Display and Photoresistance
The Display is very bright, I want that when the room is dark, he decreases the brightness.
The I2C module for the display allows you to adjust the contrast and the jumper can turn off the backlight led, but if we put in place the jumper a photoresistor (that provided by the Arduino starter kit) with the increase of the light, its resistance decreases, as a result, increases the brightness of the display, while, in low light conditions, the resistance is very high and the brightness decreases.
Step 5: DHT22
As mentioned before, I used a DHT22, although more expensive than a DHT11, because it is much more accurate.
This sensor provides the temperature and humidity of the environment. Review of adafruit (from which I used the library)
To simplify the project I used a model with built-in pull-up resistor.
The data pin is connected to pin 4 of arduino
Step 6: Buttons
The buttons, as mentioned, are used to adjust the time without reloading the sketches.
It should to be constructed a small Pull Down circuit for each button.
The Arduino pin interested in this feature are:
- Pin 6 = menu
- Pin 7 = +
- Pin 8 = -
Step 7: Assembly
I chose a junction box for 4 fruits of GEWISS because it is the perfect size for the display that I used.
Not having points of anchor, I used an electric wire to attach the display to the front mask.
The LED (in series with a 220 ohm resistor) has been glued to the hole from 0.5 mm that I did.
To protect the photoresistor, I used a piece of clear plastic thatI don’t remember where I found.
I added a master switch to turn everything off when not needed.
For the mains I used a phone battery charger with mini USB plug.
The sensor of DHT was fixed so that it is external to the box.
To connect the PIR sensor I used a 2.5 stereo jack plug.
Arduino standalone and Stripboard, with the RTC and the resistance pull down (I'm sorry that you do not see), they are attached to the rear of the box with the M3 screws.
Step 8: Arduino Code
Step 9: ...Allarm...
My laboratory is located in the basement, and when I'm working I do not feel if someone comes to visit me, so I thought about adding an alarm with a PIR sensor, a LED and a BUZZER.
The PIR sensor needs to be powered at 5 volts supplied by Arduino and connected to pin 2
The LED is connected to pin 13
The buzzer to pin 9
You have been warned !
When you want to visit me…
Warn me !!!