Ultrasonic Listening & Echolocation Hack Notes for August 10th, 2009
Eric and David have agreed to meet regularly on Monday nights to hack on the ultrasonic listening and echolocation kit idea/project. Tonight's goal: review all that we know, brain storm, and decide on a plan of attack for moving forward: what do we want to do/try first?
- we have what we think is a non-tunable hererodyne ultrasonic listening toy
- there are also frequency division & time expansion techniques/kits/products
- we know little about the Spanish scientists who are training people to do echolocation by clicking their palates
- there are also interesting "directional sound" sensors & displays
Another heterodyne eBay guy who builds them
We hooked the speaker in the Secret Sounds toy up to frequency generator. You can hear the noise up to 16kHz-22kHz (depending on your age, mostly), and the device seems to work from 10kHz-80kHz. It's much louder at lower frequencies though - not sure if this is because of the frequency response of the speaker or the microphone. I believe this confirms the device as some kind of frequency division device, but you can hear some amplitude information as well, as verified by pressing the attenuation buttons on the frequency generator.
A ultrasonic ranging device usable by blind people - or others who are interested.
 Ideas for Moving Forward
- we could investigate what frequencies it does operate with
- we could order some kits or build our own
- we could find out more, do more research about what academia/the internet knows
- we could build the Arduino 3D sound compass display
David is going to do some research into omni-directional speakers and microphones, esp. as related to ultrasonic frequencies.
Eric is going to put together a parts order for us to make a heterodyne ultrasonic detector.