Just curiosity

Hi i was wondering if smart boards work the way that there are many ultrasonic sensors in the side and then if you tap it detects the position of your finger. If so, can you do that with arduino?

What does reported to mods mean?

okay thanks!
:slight_smile:

Post a link to an example of a "smart board".

@Arduino_Matrix_guy, do not cross-post. Other thread removed.

Arduino_Matrix_guy:
Hi i was wondering if smart boards ...

What smart boards?

...R

Smart boards are the things that appear to be touch screen that teachers use in classrooms in the U.S. The image is shown with a projector and very useful for teaching because you can show a class one huge screen that you can interact with. You should be able to find it in YouTube and google

Arduino_Matrix_guy:
You should be able to find it in YouTube and google

You want help. YOU provide the link.

My time will be better spent answering another question instead of searching for the link.

...R

Even if it is touch sensitive, do you think i could recreate one except with ultrasonic sensors?
I'm not very sure the smart boards we have are touch sensitive because you could push a button on the screen with out actually touching it. You could put your finger close enough to the screen and it would consider it pushed

recreate one except with ultrasonic sensors?

No. The ultrasonic sensor cannot determine whether you have touched something.

There used to be a touch screen technology based on ultrasonic surface waves, but this is almost certainly not a hobbyist technology.

There were ultrasonic digitisers that used fixed linear arrays of microphones, with an emitter puck.

I was thinking some what along that where many of the ultrasonic sensors are places in a row sow if you touch it detected where exactly your finger is and sends a signal to another arduino the coordinates of where you touched.

How do you detect a touch, rather than just a hover?

not that sure maybe when you push down on a blank screen (the white part of the smart board) the edges can detect movement and figures out where you touched?

I think you'll find that the ultrasonic sensors (the cheap ones anyway) aren't that precise in the position of what they will measure. If you look at the datasheet for one of the most common ones, you will see the measurement angle is 15 degrees. This means that if you put your finger on the board, multiple sensors will "see" it and give you a distance measurement. You could try to make sense of this by assuming that the sensor with the shortest measurement is the one at 0 degrees, but I'm not sure you will get enough precision from these sensors to do this accurately.

What if I were to use more sensors to look at the parts that are not covered by the original ultrasonic sensors?

Arduino_Matrix_guy:
What if I were to use more sensors to look at the parts that are not covered by the original ultrasonic sensors?

I think the problem is not lack of coverage, it is too much coverage. If you draw a picture of your board and then mark the locations of where you would put the sensors. Then from each sensor, draw a line out onto the board at 15 degrees from the centre line of the sensor in both directions. This is the "beam" where the sensor will pickup an object for measurement. If you do this for all of the sensors you will see that these "beams" are overlapping, and the further from the sensor you get the more overlap you will have with other sensors.

You could spread the sensors out to try an minimise the problem, but then you will have dead areas at the edges of the board that aren't covered by any sensor.

Like I said, you may be able to work around this in code by taking the sensor with the shortest measurement or taking the middle sensor if multiple sensors are triggered. You would need to try it out in small scale to see if you can get the precision you require.