Here is a great mod for a reef(wreaths) that has LED's on it. Use the Mediatek LinkIt ONE board with a SD card to hold Holiday songs which are played when some one is at the door.
An Ultrasonic sensor is used to detect if there is someone at the door and I am using a light and small portable speaker that fits behind the reef.
In addition if you have a 3D printer , print the STL attached in step 4 to house/protect the LinkIt ONE.
Step 1: Collect the Components Required for the Build
Collecte/buy the electronic compontes you'll need
- Reef with Battery powered Leds
- LinkIt ONE board
- Lipo Battery, this comes as part of the LinkIt ONE package
- Maxbotix Ultrasonic sensor EZ1
- Grove Relay
- Grove connector to connect the relay to LinkIt ONE
- SD card to store the mp3 files that will play
- Portable speaker
- 3D printer and filament if you plan to print the part as shown in the second picture above, or you can use a Tupperware container as the enclosure
Step 2: Putting the Circuit Together
As part of the Circuit , connect the
- Maxbotix Ultrasonic sensor to Pin 2 of the LinkIt ONE
- Connect the Relay to the Serial port (Tx,Rx), using a grove connector
- Connected the Portable speaker to the LinkIt ONE audio jack
Once done , cut the wire that runs from the battery pack to the reef and connect it to the terminals of the relay as shown in the pictures above.
In addition, here upload the mp3 files to and SD Card.These will play as soon as there is someone detected in front of the reef.
Add the SD card to the slot at the back of the LinkIt ONE.
Step 3: Uploading the Code to LinkIt One
Download the Arduino sketch attached and install the latest version of the Arduino IDE
To setup the Arduino IDE for the LinkIt ONE register and create an account on the MediaTek Labs website Then follow the link below to download the latest driver and software LinkOne Board
Upload the blink example sketch that comes with the Arduino IDE and see if the LED on the LinkIt one board blinks, this is to confirm that your setup is successful.
Upload the Code to the LinkIt ONE and then Open your serial monitor to decide on far you person needs to be in front of the door to trigger the Ultrasonic sensor , in my case I have set it to 10 inches as shown in the picture above.
In addition, you may also have to change the name of the mp3 file you uploaded to the SD card as part of the previous step
Step 4: 3D Print the Components
Download the STL files attached and using 3D printing software slice and 3D print the files.If you don't have a 3D printer handy you can use one at your local maker club or library or use a 3D printing service like 3D hubs(use the pint using 3D hubs button).
In my case I am using Repetier-Host as my 3D printing software with the Printrbot Simple metal, and the slicer set at 0.2mm layer height . And printing the files should takes about couple of hours.
In addition, I am using Hatchbox green and black 1.75mm PLA filament for 3D printing.
Step 5: Zip Tieing the Components Together to the Reef
Once your are done 3D printing , add the Lipo to the base and add the LinkIt ONE on top of it and add the grove connector
Snap fit the top and connect the Maxbotix Ultrasonic sensor to Pin 2
Zip tie the relay,battery back pack and the 3D print case to the back of the reef as shown in the pictures above.
Finally tie the speakers to the reef and mount it on your door.
Happy Holidays !!