Arduino Theremin Door-close Reminder

Sometimes, we need to add some seasoning to our life, so that you ‘ll feel better and create more fun to prompt life become amazing.

My colleagues and me always forget to close the door after our meeting, and there are too many valuables in the meet room. I think keep door closed is a good manner. So how to change this status? I have a idea now, both of us like listen to music, especially light music and classical music. The voice of theremin sounds deep but melodious. It always make me feel comfortable. Although we are engineer, we also enjoy life with “massaging” our ears. How about to make theremin by Arduino? It seems well if we could play the music with the process of closing the door. When we start to work, some of problems encountered, such as how to make the sound feel more comfortable and set the effective range and so on, these have been solved by modifying the program. Arduino is a easy but powerful tool, we complete finish this project as it cost just several hours.

Ok, now we started to close the door, can you hear that? DO,RE,ME,FA,SO,LA,SI. A funny project to change your bad habit. You’ll fall in love with it.

Let’s work together to build the hardware part, first of all, you need to prepare these modules:

1: Crowduino Uno-SD V1.5 x 1

2: 4 Pin Crowtail to Male Splittable Jumper Wire(5 pcs）x1

3: Crowtail- Ultrasonic Ranging Sensor x1

4: 40mm Mini Speaker 2w 8ohm x 1

5: Jumper Wire x 6

6: Audio Amplifier PAM8403 with Colume Control x1

Ok, let’s get going! Put the Crowduino UNO on the table, and then we take out our “keys”- Crowtail- ultrasonic ranging sensor, yep! We play the theremin by invisible touch with this sensor, it has a corwtail interface so that we can use the 4 pin Crowtail to male splittable jumper wire directly. Note these line:

Black line –GND

Red line- VCC

White line- Echo

Yellow line- Trig

The white line connect to D12, and yellow line connect to D11，red line connect to 5V, black line connect to GND.

The next, an important character will be played, it’s a audio amplifier PAM8403, it will promote the colume output. You can adjust the volume by the knob, and it has two kinds of audio output: L-OUT and R-OUT. Choose any one as you want. Then connect the L-INPUT/R-INPUT to D9, G-INPUT connect to GND, also its power should be supply by Crowduino, according the connection as shown.

In the end, we need to add a nice “voice” to it so that it can issued a wonderful voice. Yeah! We choose a 40mm mini speaker to play this role, we need to weld the jumper wire to the speaker, the red one connects to the “+”, the black one connects to the “-”. This speaker should be connected with audio amplifier, we choose the L-OUT as audio output this time, according the connection as shown.

All in all, a basic hardware module structures has been finished.It's time to upload the progam to crowduino, you can found the program in the attached files, download it and unzip, then open and upload the program with Ardunino IDE tool. Now we can have a test, power it with a 9V 1A DC power adapter. Use your hand to get close to the ultrasonic sensor slowly, it will issued a changing tone of voice. You can even try to play simple melodies.

At last, we fix it behind the door, now it’s time to enjoy the process of closing a door. Undoubtedly, it obtains everybody’s consistent high praise.

A fun little project, help you to change your bad habits. Love music, love life, love DIY.