by A Cassandra.
told in part from the point of view of a child who is deaf and blind
Ian and the new thing
It's a cold morning, Ian thought as the hands-on his shoulders steered him forward and left. He could smell petrol fumes, and there had been enough meals, It is morning, Ma is putting me in the car seat. And it's purring. I'm going to the toy's room. Ian was happy about this, he likes the toy's room its soft and interesting and last time there was a new thing. A new thing that was like the cold hard place, where the air shakes Ian and makes him feel good all the way through. First back then forward then back and right, Ian knows the order he gets tipped for the toy's room. Forward, right and back, back, then nothing but the purring gets more urgent. Thud, thud, thud, hard forwards, left rough shaky, forward, stop. Must get out of the car seat. Ma helped Ian out of the car seat. Ian holds out his hand like he had been taught. Ian hopes it would not be the bad hand, the bad hand goes to the flashy room. It is the good hand. Ian followed it quickly to the toy's room. The new thing is there. Ian can almost imagine that he is controlling it.
Margaret had to get her son to the day centre, then five hours.
The car's engine has to be running before she can strap Ian into his car seat, or he will kick off.
Driving to the centre she had to keep her speed down, anything over thirty, and he will start screaming.
At the centre, she has to get him out of the car quickly before he gets himself tangled trying to free himself. As soon as he is out he stands there hand out waiting for Karen to lead him inside as always.
Karen genteelly scooped his hand in her left hand. She leads him in through the main door. Round a left-hand corner and to one of the soft playrooms on the left. This set of playrooms has lots of soft toys with all sorts of different textures. In the last three weeks, they have added a couple of bass theremins for the profoundly deaf students. For the students that like them, they can be a real motivator. Though some of the staff complain about the noise.
Margaret got into her car. Five guilty hours a week
Again with annotation.
Margaret had to get her son to the day centre, then five hours.
The car's engine as to be running before she can strap Ian in <the vibrations of the engine are reassuring to Ian. Although he does not remember it a rushed trip to the hospital has left him afraid of the car seat when it is not vibrating.>
Driving to the centre she had to keep her speed down, <To understand imagine that you are flying a jumbo jet flight simulator through a terrible storm. Then some idiot turns of all the lights, instruments, and controls. Leaving you strapped to a chair inside a black box that is getting tossed around like a plane in a storm. Scary.>
At the centre, she has to get him out of the car quickly before he gets himself tangled trying to free himself. As soon as he is out he stands there hand out waiting for Karen to lead him inside as always. <when he holds out his hand Ian does not know if it will be Karen's right hand that will lead to the visual sensory room. Or her left hand, which leads to the toys. But he has learned to be lead.>
Karen genteelly scooped his hand in her left hand. She leads him in through the main door. Round a left-hand corner and to one of the soft playrooms on the left. This set of playrooms has lots of soft toys with all sorts of different textures. In the last three weeks, they have added a couple of bass theremin <The bass thiamine is a small battery-powered Tupperware box. It is really loud so much so that it makes the room and that is the profoundly deaf students, who aren't afraid of it love it. The noise it makes is like a cross between a cathedral pipe organ, an out-of-tune tuba, and a big industrial machine grinding to a halt. For Karen, the most interesting thing is watching students learn that they can have an effect on the universe beyond the length of their arms.>
Margaret got into her car Five guilty hours a week <she knew she shouldn't feel guilty. She had learned to put on a good show for Karen and the others. She needed this little bit of time.>
A bass theremin, for use as a field magnetometer. A playable very-low-frequency oscillator, for live dance music. Or as a sensory toy for children who are deaf and blind. For use as a sensory toy, it would need to produce its loudest volume at low frequencies.
A bass theremin can be made as follows.
(1) the movements of the player arms are detected by their effect on the inductance of a coil. A coil that is the same as the search coil of an old fashion beat frequency oscillation metal detector (bfo-md).
(2) that coil is the inductor of an LC radio frequency oscillator as in a bfo-md.
(3) the output of this oscillator is divided into two streams. The first of those output streams are passed to a mixer, as for a bfo-md.
(4) the second output stream is passed through a delay line, then after a seventh of a second this signal is passed to the mixer.
To summarize to this point it is a simple beat frequency oscillator metal detector, but with the fixed reference oscillator being replaced by a time-delayed copy of the radio frequency search oscillator.
For a magnetometer or a musical instrument, an audio amplifier is used in combination with audio filters and a speaker to play the output from the mixer.
For the sensory toy, the output from the mixer is fed into an auxetophone or my modern version of one. The auxetophone is an old technology for amplifying sound, that pre-dates electronic amplifiers.
It consisted of a type of mechanical valve that releases pulses of compressed air. Originally it was controlled by a gramophone needle, to play music. It is best suited to playing lower frequency at loud volumes. A large volume of rapidly moving air equals a loud sound.
Using modern technology a very simple auxetophone can be made out of a small rotary compressor powered by a fast controllable electric motor. The motor needs to be powerful and controllable enough to go from rest to full speed and back to rest, fifty times per second. This motor will need to be larger than would be necessary to drive the compressor at a steady speed. To use this as an auxetophone the speed of the motor will need to be controlled to match the amplitude of the output of the mixer after it has passed through a 45 Hz low pass filter.