It is good advice to change batteries in your fire alarms at least once a year. Even our low-power LCD calculators need new batteries from time to time. But at the University of Oxford, they have an electric bell that has been ringing essentially non-stop on one set of batteries for about 178 years! Is the energy crisis solved then? Perhaps not. The bells require a high voltage but very little current and the pair of batteries — piles in the parlance of 1840 — have kept the charge flowing for about 10 billion rings. As you can see in the video below, though, the ringing isn’t very vigorous.
How does it work? When you think of converting electrical power to mechanical motion you probably think of a motor, even though there are plenty of other transducers like speakers, muscle wires, and solenoids. Arguably the first device was electrostatic bells that were invented by a Scot named [Andrew Gordon] around 1742. [Ben Franklin] made them famous, though, so they are often called Franklin bells.
Continue reading “The Bells! The Bells! One Battery since 1840”
[MeasuredWorkshop] wanted to know how a boxing bell mechanism worked. The best way to learn is by doing, so he jumped right in and built one! Boxing bells are a rare surviving example of the trip bell mechanism. Trip bells were used in schools and public buildings as fire alarms. They’ve since been replaced by modern electric systems.
The mechanical linkage behind the trip bell is a one-way lever. This is the arm you pull on. It has a hinged section which stays rigid when the arm is pulled down, but rotates away when the arm is released. [Measured Workshop] built the mechanics of his bell using rather basic tools. The brunt of the work was handled by an angle grinder and a drill press.
The sounder for this boxing bell came from an old school bell. The industrial grey paint was chemically stripped, and the metal cleaned up for a nice brushed finish. The metal stands out nicely against the wood board [Measured Workshop] used as a base.
The finished product looks and sounds the part – now he just has to find a boxing gym in need of a bell!
We’re really becoming fond of the “wordless workshop” style videos that have been popping up on YouTube. [Jimmy DiResta] has been doing it for years, and relative newcomers [HandToolRescue] and [Measured Workshop] are both producing some great content!
Continue reading “This Boxing Bell is a Trip”
[James] sent us a video of his latest creation: a robotic glockenspiel that’s currently set up to play “Popcorn”. It uses eight servos to drive mallets that strike the tone bars with fast, crisp movements. The servos are driven with a 16-channel I²C servo driver and MIDI shield, which are in turn controlled with an Arduino Uno. The previous incarnation of his autoglockenspiel employed solenoids, dowels, and elastic bands.
[Gershon Kingsley]’s 1969 composition for synthesizer “Popcorn” has been covered by many artists over the years, though perhaps the most popular cut was [Hot Butter]’s 1972 release. Check it out after the break, and dig that lovely cable management. We’d love to see [James]’s autoglockenspiel play “Flight of the Bumblebee” next.
If you’re hungry for more electro-acoustic creations, have a gander at [Aaron Sherwood]’s Magnetophone.
Continue reading “Robotic Glockenspiel Crunches “Popcorn””
We’ve got to say it… these tubular bells sound awful! They don’t really have a tight pitch center so they sound really out of tune to us. But we think that’s the failing of the instrument itself and not the work which [Tolaemon] did to automate the instrument.
There are three main parts to his project. The first, which is shown above, adds a hammer for each bell. The hammers are hinged, with one side being pulled by a solenoid in order to strike the bell. The second part of the hack also uses solenoids, dampening the bell’s ability to ring by pressing a felt pad up against the bottom of the tube. The final portion of the project brings it all home by adding MIDI control to the hardware.
The clip after the break gives a good overview of the different features including some preprogrammed playback as well as direct control of the instrument using an electric keyboard. This reminds us of that scratch-built solenoid xylophone.
Continue reading “Automatic tubular bells given a MIDI interface too”
The folks over at [Soup], a British marketing agency, thought up this cool project. It’s a set of handbells hooked up to an Arduino, actuated by central locking motors found in car doors. By the look of some pictures, there was also a Lego version. Songs written by users (through the online interface) are placed in the que of a server. Once it’s time for the song to be played, serproxy sends the Arduino an appropriate set of commands for ringing the bells in sequence. All of this happens in the [Soup] office while it is streaming live through a webcam.
We think that this is definitely a great way to use surplus auto parts. After all, not everyone can build helicopters.
It seems as though the bells are down for the moment, or the employees got a bit annoyed at hearing them constantly ring.