For my first year in NMCT at Howest we had to make ourselves a project at the end of the year. I decided to go with some kind of smart wall calendar. I went with that idea because I usually forget to add upcoming events to the classic paper calendar and just add it to my personal google calendar on my phone. So I thought that a smart calendar would be rather usefull if I could connect my google calendar to a display on the wall.
We had to use 3 sensors (preferably reused) so than I picked out the 3 most usefull sensors:
- ds18b20 (temperature)
- DHT11 (humidity)
underneath this you'll find the complete item list and the corresponding websites I got the extra components from.
I would suggest you start of with a starter kit because most of them already have the required sensors within them.
On this page I will show you how to build the calendar from scratch, showing you the events from your or multiple google calendars. The raspberry pi will serve as a server for my database which will store humidity, temperature and the amount of time someone stood in front of the calendar. The website will also run on the pi which will show you the saved data from the last couple of days. The whole calendar will work using the PIR, which will turn the screen on when motion is detected.
1x passive infrared sensor
1x DHT11 humidity/temperature sensor
1x raspberry pi (preferably from a kit, the sensors above are usually already in that kit as well as the adapter)
1x external screen (recovered from old pc)
1x LVDS driver (you need the serial number to get the correct driver, this is shown in step 2)
1x power supply adapter for the LVDS driver
1x t-cobbler and connector
1x HMDI (a short one)
1x sticky nail (I used a tesa nail)
wood or any other material you want your case to be made out of
Step 1: Setting Up the Hardware
In the image you can see how I wired the project. The 2 resistors I used both have 4700 ohm as their value. I used a program called fritzing to make sure all components are properly connected. Once you've done this the electrical part of the project is almost completed.
Step 2: Changing Your Lcd Screen Into Your Calendar Screen
As I said before i got my screen from an old laptop that hasn't been used for years. You can easily do this yourself by just unscrew the 2 screws that are underneath the small circles at te bottom of your monitor. When you have done that you can unclip the screen, a little force is necessary so don't be afraid to push a little harder. Be careful that you don't rip any little wires apart and make sure you disconnect the wires without doing any damage to them. Once you've taken out the screen completely safe you can check the backside for the serial number. When you're ordering your LVDS driver, the seller should ask you for the serial number so they can configure the driver to work with your screen.
Step 3: Setting Up the Software
Step 4: Creating Your Frame
For this step I took the meassurements of the screen and added some margin to all the sides, so I could be sure that everything would fit in nicely. The case itself is made out of multiplex, 0.8 cm in thickness. Once I got the multiplex I used a lasercutter to cut out the design as seen in the picture. The plank itself was pretty sharp so I used sandpaper to make the edges a little smoother and more child friendly. When all this was done I spray painted it black which gave it a smooth matt black look.
As you can see in the scheme I created holes in seperate locations to fit both the PIR and the DHT11. The ds18b20 can be placed all around the screen where you prefer it. I placed it above the screen because I created holes in both the bottom and top panel so there's a little bit of airflow. (so it doesn't affect the ds18b20)
Step 5: Final Touches
With all the previous steps being done you can easily go to a hardware store and get yourself the sticky nail and place it on the wall where you want to hang the calendar. The case and hardware itself does not weigh that much so the nail should easily be able to hang it up. Do keep in mind that you do need 2 plug sockets, one for your raspberry pi and one for your LVDS driver. So that's that, now you got yourself a fully functioning smart calendar on your wall.