Go Down

Topic: GAP SENSOR (Read 488 times) previous topic - next topic

ChinmayVirmani

Jun 11, 2018, 07:24 am Last Edit: Jun 11, 2018, 07:28 am by ChinmayVirmani
I want to measure a very tiny gap of about 20-30 microns(0.02-0.03 mm) using a sensor with the help of arduino and then display it using a 16x2 Digital LCD Display. Can someone help me out with the sensor that I will need for this purpose with exact name and its working.

The gap that I want to measure is the gap between the the joints of a healing fractured bone.(the joint where the tissues develop to join the broken parts together.)

For further reference you can refer to the following attached image as it will help you out with the type of gap I want to measure.

mikb55

Is this in vitro or vivo?

wvmarle

It looks like the sensors you show are optical - probably making use of image processing. Whatever processor is doing this, will be far more capable than an Arduino.

For your bone fractures, the hard part is the sensor. This are tiny distances, several orders of magnitude less than the gaps in your images.

I assume you need contactless, and at 20-30 micron optical is the only option (it's too small for sound waves). If it's inside the body, that'd be x-ray.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

ChinmayVirmani

It looks like the sensors you show are optical - probably making use of image processing. Whatever processor is doing this, will be far more capable than an Arduino.

For your bone fractures, the hard part is the sensor. This are tiny distances, several orders of magnitude less than the gaps in your images.

I assume you need contactless, and at 20-30 micron optical is the only option (it's too small for sound waves). If it's inside the body, that'd be x-ray.
Can I know how will the optical sensor measure the gap I require.

wvmarle

Take x-ray photo; process the image.

I remember when I had my fingers broken that the doctor was setting my bones (forcefully) while looking at an x-ray video feed of my fingers to see what he was really doing. So that's possible at least.

No matter, Arduinos are pretty much out of the picture here.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

ChinmayVirmani

#5
Jun 12, 2018, 02:44 pm Last Edit: Jun 12, 2018, 02:45 pm by ChinmayVirmani
Take x-ray photo; process the image.

I remember when I had my fingers broken that the doctor was setting my bones (forcefully) while looking at an x-ray video feed of my fingers to see what he was really doing. So that's possible at least.

No matter, Arduinos are pretty much out of the picture here.
Will see to that. Although image processing will be difficult in my case as I have still not studied that.

ChinmayVirmani

Is there anyone else who can suggest me something for this?

vffgaston

Is there anyone else who can suggest me something for this?
Hi,
Yes: what is the uncertainty on determining the (broken) bone end?
Can you provide some picture on a broken bone and where are you planing to -exactly- measure microns?
Regards.

ChinmayVirmani

#8
Jun 15, 2018, 06:43 am Last Edit: Jun 15, 2018, 06:52 am by ChinmayVirmani
Hi,
Yes: what is the uncertainty on determining the (broken) bone end?
Can you provide some picture on a broken bone and where are you planing to -exactly- measure microns?
Regards.
Hi,
Please find the attachments of the bone and the gap I want to measure.
Since this is a leg bone any person walking with such a fractured bone will put pressure on the bone and the gap present in the bone will reduce. So that is what I want to measure using a sensor and arduino. Since this gap will be too small (20-30 microns) I am unable to find a suitable sensor for the same.

wvmarle

That's not a 20-30 micron gap. More like 2-3 mm, which is 5 orders of magnitude different.

Also I've never before seen a fracture that looks like it's been made with a saw.

Without meat on the bone walking with it will be really hard.

I may be missing something, but there doesn't seem to be much relationship between the cut in that piece of bone shaped plastic on the photo, and the actual crack in a living bone in a living person that I understand is what you want to measure.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

ChinmayVirmani

#10
Jun 15, 2018, 08:22 am Last Edit: Jun 15, 2018, 08:41 am by ChinmayVirmani
That's not a 20-30 micron gap. More like 2-3 mm, which is 5 orders of magnitude different.

Also I've never before seen a fracture that looks like it's been made with a saw.

Without meat on the bone walking with it will be really hard.

I may be missing something, but there doesn't seem to be much relationship between the cut in that piece of bone shaped plastic on the photo, and the actual crack in a living bone in a living person that I understand is what you want to measure.
I know that's not a 20-30 micron gap. But  when pressure/force is applied on to the bone while walking the gap will reach close to 20-30 microns.

Also with regards to your reply of meat on the bone and the fracture made with saw it is the prototype made of wood I am working upon. Once I am done with that after that I will be implementing it on the actual bone.

Main issue I am facing is the measurement of gap using a sensor and arduino.

Also the thing I am doing is a close case of greenstick fracture.
refer to the attachment of fracture.

wvmarle

You mean the actual bone will have a saw cut in it, and then by pressure the gap is kept closed?

Not planning to stabilise this bone with metal plates and screws as surgeons normally do to set a broken bone?

Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

ChinmayVirmani

#12
Jun 15, 2018, 08:55 am Last Edit: Jun 15, 2018, 08:57 am by ChinmayVirmani
You mean the actual bone will have a saw cut in it, and then by pressure the gap is kept closed?

Not planning to stabilise this bone with metal plates and screws as surgeons normally do to set a broken bone?


It wont have a saw cut in it. It will be somewhat like the greenstick fracture I attached in my last reply.

Also it will be done with plates and screws as it is normally done but still there is a need to measure the gap because for the growth of tissues(they join the two parts together during healing and make it a complete bone ) we need to maintain a specific distance between the two parts because if its not done the tissues get damaged and also new tissue formation is hindered and the bone healing does not take place.

wvmarle

There are materials that change resistance when strained or compressed, maybe you could attach a material like that to the bone spanning the gap. I really don't know if your sub-micron changes can be detected with such a material (you want to measure a gap of 20-30 micron, so I assume you're looking for a resolution of 0.1┬Ám or better).

Reading the thing is tricky as of course the rest of the leg is in the way so you would have some wires coming out through the skin or so, or you have to build a tiny device that goes inside the body and can be read wirelessly. You would need a second operation to remove the thing after the bone has healed.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

vffgaston

...  walking with such a fractured bone will put pressure on the bone and the gap present in the bone will reduce ...
Hi,
Although I have  fractured several bones (mainly because cycling falling; last one a year ago: I have a titanium plate and seven nails in my left elbow), I do not deem myself a fracture expert, so I will not make any statement about the possibility of walking with a bone such broken ...
I understand that the -the two disjointed parts of the- bone move because the patient "walks", but I doubt this displacement has the order of magnitude of microns (and that the two pieces just move in the same axis without rotating each one with respect to the other and moving sideways also ...).
In what concerns bone growing, things are a bit different: if the fracture is reduced by using metal plates, you (I) can imagine measuring the bone growing in such a slow rate that you can measure the growing in microns. Nevertheless, fracture is so irregular that I could not imagine even how to select the two points (one in each part of the broken bone) to measure it.
Regards

Go Up