Help please

[wowowee]

okay, nevermind the previous question. what if i place the ultrasonic range meter flat on the ground(floor)? will the ultrasonic module detect the floor?

 

[Nigel Goodwin]

You need to make one and try!.

 

[wowowee]

You need to make one and try!.

i tried to make one but there are some components of the circuit that are not available in our place. availability of the materials is really one of the biggest problems that i'm facing right now.

 

[Nigel Goodwin]

Perhaps if you had your location filled in we might know where you were?.

 

[wowowee]

Perhaps if you had your location filled in we might know where you were?.

okay i'll change my profile and fill it up. anyway, i'm from the philippines.

 

[Nigel Goodwin]

okay i'll change my profile and fill it up. anyway, i'm from the philippines.

There are quite a few members from the Philippines, what parts are you having trouble sourcing?.

 

[wowowee]

There are quite a few members from the Philippines, what parts are you having trouble sourcing?.

yeah, i only know one though (penoy_balut). i don't have the list of the parts yet, maybe later. actually, there is an rs components shop in the philippines but its only in manila and i'm not from there.

anyway, i got another question. considering the two ultrasonic range meter prototypes facing each other, when a wave is transmitted from one of the prototype and the receiver from the other prototype sensed it, will it still produce a reflection?

**broken link removed**

 

[Nigel Goodwin]

Depends what you mean by a 'reflection', the second receiver will consider the incoming wave as a reflection from it's own transmission, and give a false reading.

 

[wowowee]

Depends what you mean by a 'reflection', the second receiver will consider the incoming wave as a reflection from it's own transmission, and give a false reading.

i mean the echo. but can you still compute the time of arrival if a transmitter and a receiver faces each other with different microcontrollers? you can't right?

 

[wowowee]

i guess you can't.

Only if they transmit at different times - otherwise the tranmission from the other one could be mistaken for a reflection and give the wrong range.

how can you transmit it at different times? i'm comfused.

 

[Nigel Goodwin]

i guess you can't.



how can you transmit it at different times? i'm comfused.

Ranging is done using pulses, one transmitter sends out a short pulse, and the receiver times the echo coming back. As long as another transmitter doesn't transmit while the receiver is waiting for it's own echo, then there would be no problem.

 

[wowowee]

okay. thanks sir.

 

[wowowee]

i got another question. in timing the reflecting echo, is there a limit in the distance between the ultrasonic transmitter and receiver? and should it be parallel to each other?

 

[Nigel Goodwin]

Obviously if they are close together, and parallel, a pulse bouncing directly back will have the best chance of hitting the receiver. Uusally they are set about an inch apart or so, you don't want them too close as the transmitted pulse may overload the receiver.

 

[wowowee]

Obviously if they are close together, and parallel, a pulse bouncing directly back will have the best chance of hitting the receiver. Uusally they are set about an inch apart or so, you don't want them too close as the transmitted pulse may overload the receiver.

okay. lets say that the modules are about 8 inches apart. will the transmitted pulse still be received by the receiver?

 

[Nigel Goodwin]

okay. lets say that the modules are about 8 inches apart. will the transmitted pulse still be received by the receiver?

Probably, but with reduced sensitivity?.