Hi all,
So a quick background on myself. I'm sort of a bumble my way through type of person when it comes to electronics and programming etc.
I am hoping somebody can guide me with something as I have minimal experience when it comes to arduino.
I would like to have approx. 15 x HC-SR04 which can all take measurement at the same time. each individual sensor would have to have its own measurement. The sensors would be spaced 5mm apart.
all I want the output to be is a simple number (being the distance the sensor is from the object).
What arduino do I need to make this happen. Am I even speaking English?
is there someone willing to assist with most of the project?
It would be simplest to use a Mega as that has lots of pins and you require two pins for each distance sensor.
Just take the readings one at a time and leave a gap between measurements to allow the echoes to die down. I would also add extra decoupling capacitors to each sensor.
HI,
I don't think you will be able to take all 15 sonar readings at once.
This is because all the units Tx on the same frequency and they are not narrow in their beamwidth.
Each unit will receive not only its refection but any other from the other units, creating a false distance.
You will have to ping each one after the other so they only receive there own reflection.
Tom...... 
Or use one unit and swing scan it on a servo, pinging it at intervals.
TomGeorge:
HI,
I don't think you will be able to take all 15 sonar readings at once.
This is because all the units Tx on the same frequency and they are not narrow in their beamwidth.
Each unit will receive not only its refection but any other from the other units, creating a false distance.
You will have to ping each one after the other so they only receive there own reflection.
Tom......
Or use one unit and swing scan it on a servo, pinging it at intervals.
it might be possible to have units 1, 4, 7, 10, 13 ping at once, if they do not effect their neighbors
then 2,5,8,11,14 so that instead of 15 iterations, one has 3
or maybe toggle each so that every odd number checks, then shuts off so it does not listen, then every even number
Please read this article on the Beam Width of the HC-SR04 ultrasonic ranging module
http://www.swanrobotics.com/projects/hc-sr04_project/
The measuring angle from the HC-SR04 is 15 degree. At 4 meter distance this should be a beam of about 1 meter. At 1 meter this is 26 cm so we have to keep this in mind when using this information.
bradleym:
The sensors would be spaced 5mm apart.
all I want the output to be is a simple number (being the distance the sensor is from the object).
What distance are you measuring? 5mm apart is not right. you will not getting useful information for that spacing.
may be another case of XY Problem.
Hi,
Thanks for the help. Is there somewhere I can find data sheets easily for arduino products?
I didn't have much time yesterday to find information on the sensor so did not know range and span of Tx from the sensor etc.
Tom, the servo might be the way to go.
Thanks for the input.
bradleym:
Hi,
Thanks for the help. Is there somewhere I can find data sheets easily for arduino products?
Just Google the part number and datasheet ( e.g. 'HC-SR04 datasheet') and you'll get several hits.