<Rumo>
an automated noise maker
Godfried-Willem RAES
2014-...
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<Rumo>
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<Rumo>
This robot was named after Luigi Russolo, the most wellknown musician-member
of the futurist movement at the start of the 20th century. Just like in his
pretty primitive designs, we make extensive use of acoustical amplifiers in
this design. So, in a way, building further on principles highly developed during
the period mechanical roll players and grammophones were developed. The sound
sources used here are mainly springs, steel ribbons, membranes and rubbed strings.
It consist of a variety of very different non-pitched noise sources. Here is an overview:
1.-Excited spring with acoustic amplifier: This component uses a very long
spring held between the anchor of an electromagnet at one side, and the membrane
of an acoustic compressor at the other side. The acoustic compressor is coupled
to a conical horn, in fact taken from an old bugle. The resonant frequency of
the horn corresponds to midi note 56.
2. A second second sound source with similar excitation and membrane. For this
one we modified a compressed air horn.
3. The third sound source is again a spring, but this time coupled to a brass
membrane on a modified ships horn. The electromagnet used here is taken from
a door closing mechanism.
4. A fourth horn, a linear cone in brass taken from an antique hooter, uses a smaller membrane again made of polyacetate.
5. A modified signal horn with a steel membrane, coupled to a very fine spring rubbed with a small DC motor.
Midi implementation and mapping:
| subject to changes during the building process |
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Construction diary:
12.06.2014: Construction of the first electromagnet assembly. Testing of force
and functionality.
13.06.2014: Construction of the acoustic amplifier with a horn. The membrane
was made from polyacetate
14.06.2014: Welding of a holding construction for the horn and the driver electromagnet.
15.06.2014: Selection of suitable horns for the construction of more acoutstic
amplifiers.
16.06.2014: Construction of the membrane for a second acoustic amplifier. Design
of the mounting.
17.06.2014: Discovered another identical electromagnet in our junkyard. Mounting
flange for the second horn welded. Horn re-assembled with the acoustic amplifier.
20.06.2014: Works on the construction of a thirth membrane amplifier, now using
a thin brass membrane. 
21.06.2014: Sketching of possibilities for an overall shape of the rumo robot.
22.06.2014: Another conical brass part found at the flea market. Useable for
a linear horn and a small membrane. Silver soldering works on the combined structure.
Orifice size for this one is 8 mm. The membrane could be polyacetate, steel
or hard brass.
23.06.2014: Experiments with door closing electromagnets, as these have very
high holding force. DC-Motor experiments for rubbing strings conducted as well.
24.06.2014: Mounting of the third horn assembly on the main structure. Electric
tests: the electromagnet is designed for 12V (5W) at 100% duty cycle.
26.06.2014:Some new DC motors ordered from Farnell. Required for the spring
rubbing mechanism. Work for <Rumo> slowed down a bit, as we needed to
be working on <Zi>.
30.06.2014: Start of adding testcode in GMT. Further work on <Rumo> postponed,
as we have to get on with <Zi> first... It looks
like we cannot advance until at least november 2014...
13.09.2015: Time-space in sight to go on with the works on <Rumo>...
Maintenance information:
Electromagnets used for the two springs with acoustical membrane amplifiers: Grundig Radio Werke Gmbh, Relaismagnet 38/33. DC resistance: 55 Ohm. These components were taken from relays. They have a laminated core and thus can be operated with AC..
by Godfried-Willem Raes
Further reading on this topic (some in dutch):