Very cool. There was something on HN about a year ago about why ultrasound machines are so expensive. This might provide some background on why something low cost makes sense.
The most enlightening comment there was the one that contained this:
"Still I ended up north of $3k for hardware, and several hundred projected work-hours. A lot of the cost comes from needing 50-100 transducers to get a useable image."
Ah, that makes a lot of sense - I was trying to find information on how ultrasound machines worked awhile ago, and most of the information I found just said that a ceramic piezo is used to emit the sound and measure the time until it returned. I could not fathom at the time what kind of math must be required to get a 2D image out of a single data point like that, and I couldn't find much elaboration on the subject.
But if it's just a few hundred piezos in an array, now THAT makes a lot more sense.
It's not an array of piezos (or at least, not a one-per-column array of transducers). It's a phased array which they use to rapidly scan the volume, iirc something like 32 emitters and a single receiver in a commercial unit.
Source: I looked into building one last time we had a baby but didn't get around to it.
Yep. Array is the keyword that makes it easier to Google...phased arrays, curved arrays, etc. And of course, with a bunch of piezos, your signal processing problem is larger.
The point being that on these experiments, the sensor isn't an array of piezos, rather a single-element piezo. Cuts the costs (a fab invoices around 100-200e for such a sensor), but lowers the overall image quality.
Before trolling a bit, I remember the main costs don't come from hardware (though it definitely costs something) - rather for r&d, patents, and most of all proper certification, since, in the end, it's a matter of life and death.
That being said, this experiment is mostly a dev kit to help curious tinkerers explore the topic :)
Yes. Just come up with a non-medical/safety use for it and you are good. Check your car's engine to see if it will last through the next race - a very useful thing to do and nobody will think twice. Check a boiler to be sure it won't explode - you better get this right or people will die so don't talk about potential uses here.
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Very cool. There was something on HN about a year ago about why ultrasound machines are so expensive. This might provide some background on why something low cost makes sense.
https://news.ycombinator.com/item?id=13230741
The most enlightening comment there was the one that contained this:
"Still I ended up north of $3k for hardware, and several hundred projected work-hours. A lot of the cost comes from needing 50-100 transducers to get a useable image."
https://news.ycombinator.com/item?id=13231831
So you can make a very low cost one, but you trade off what use cases it's good for.
Ah, that makes a lot of sense - I was trying to find information on how ultrasound machines worked awhile ago, and most of the information I found just said that a ceramic piezo is used to emit the sound and measure the time until it returned. I could not fathom at the time what kind of math must be required to get a 2D image out of a single data point like that, and I couldn't find much elaboration on the subject.
But if it's just a few hundred piezos in an array, now THAT makes a lot more sense.
It's not an array of piezos (or at least, not a one-per-column array of transducers). It's a phased array which they use to rapidly scan the volume, iirc something like 32 emitters and a single receiver in a commercial unit.
Source: I looked into building one last time we had a baby but didn't get around to it.
Yep. Array is the keyword that makes it easier to Google...phased arrays, curved arrays, etc. And of course, with a bunch of piezos, your signal processing problem is larger.
The point being that on these experiments, the sensor isn't an array of piezos, rather a single-element piezo. Cuts the costs (a fab invoices around 100-200e for such a sensor), but lowers the overall image quality.
I wonder if two sensors placed at a distance can make a huge difference, and how/if the image quality converges as you increase sensors.
One of the next experiment is to try with 8 small elements ;)
Before trolling a bit, I remember the main costs don't come from hardware (though it definitely costs something) - rather for r&d, patents, and most of all proper certification, since, in the end, it's a matter of life and death. That being said, this experiment is mostly a dev kit to help curious tinkerers explore the topic :)
But also if you can't afford one.
You don't go to jail for not building one.
Am I allowed to built an ultrasonic probe the way I want if I don't use it on anybody else but me ?
Yes. Just come up with a non-medical/safety use for it and you are good. Check your car's engine to see if it will last through the next race - a very useful thing to do and nobody will think twice. Check a boiler to be sure it won't explode - you better get this right or people will die so don't talk about potential uses here.
Yes, more and more (since I started reusing old devices), I wished I could inspect things non invasively. To find locking or friction points.
I guess nothing prevents you from doing so :)