I have no musical ability. And besides, people have been making music a very long time. Is there anything I could create that is both easy to play and novel? Here is what I came up with:
- Wind Chimes: They more or less play themselves
- Internet of Things: It's new (kind of) and all the rage :-)
These are the project objectives:
- Easily constructed
- Can connect to the internet
- Can be muted when no one wants to hear it
- Can work in the normal fashion when there is wind
- Can check the weather and automate itself when there is no wind
The main challenges in this project seemed to be mechanical so I started with this cartoon:
An inexpensive ESP-8266 will provide access to the internet and drive a servo to move the striker back and forth and thus ring the chimes. Not shown is a wind sail which would hang below the striker and ring the chimes in the traditional fashion when there is a breeze.
The making of the chimes is interesting and Lee Hite has a very good description of how to do it: An Engineering Approach to Wind Chime Design. I recommend a quick perusal even if you don't plan on making chimes for the sheer geekiness of it.
A feature (flaw?) of my design is that multiple tubular chimes will be struck more or less at the same time. For this reason they should be pleasing to the ear when this happens - I chose to use the pentatonic scale. I also chose to make the chimes from 3/4" copper tubing which I thought attractive and is readily available locally in six foot lengths. Mr. Hite gives the information to make chimes from other materials and in metric as well as imperial dimensions. My design is in the key of A which allowed maximum use of the six foot length. The full mechanical details for the tubes are recorded in the table below:
This was one of those projects where I just started building without planning any more than what is described above. I cut the chimes to length with a hack saw and drilled a hole through both sides at the hang point with my trusty electric drill. The burrs in the holes for the hang points were removed with a small "rat tail" file. Shown below are the finished chime tubes:
The support platform and striker were cut from scrap 5mm plywood to the same size (approximately 7 inch diameter) with a reciprocating jig saw. Then equidistant 1-3/4 inch holes were drilled in the striker plate about 2 inches in from the outside edge for the tubes to hang through. A 1/4 in dowel long enough to pass through the center of the support platform was glued into a friction fit hole in the center of the striker.
The tubes were hung from the support plate with fishing line (Steelon leader) with the bottoms aligned. The striker was suspended from three points a few inches above the bottom of the tubes and the dowel passed through a hole in the support platform large enough to allow it to rotate and move freely.
A servo was then mounted on the support platform using cable zip ties and the horn of the servo connected to the dowel with fishing line.
The nearly complete mechanism is shown below with the center dowel pulled tight such that it mutes the chime..
A servo was connected to an ESP-8266 (Wemos D1 mini) and programmed with the Arduino IDE. The servo example was modified and uses the random function to set the interval between strikes and try and get a natural sound.
Apologies for the poor sound quality. Here it is working, and this being Seattle, it started to rain as I made the video:
- The design procedure for the chimes worked well and they sound good to my ear
- When pulled and held, the mechanism effectively mutes the chimes
- The servo was noisy - consider using a quieter DC motor and maybe a cam mechanism to drive the striker
- Plywood dulls the sound from the striker and different materials / edge shape should be explored
Due to time constraints this ended up being a concept demonstration rather than a completed project. Should I continue there are obvious improvements to the build quality as well as addressing the two items in the minus list above. Andreas Spiess describes how Adafruit IO could be used to give smart phone and internet access. He also describes a method that could be used to pull data like wind speed off the internet with an ESP-8266 to further automate.
Thanks for reading and be thankful I did not try to play a musical instrument for you!
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