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Topic: morse code through ultrasounds !!!!!!!! (Read 654 times) previous topic - next topic

kourpetis

Hello i am working on a project the last year now but the lack of knowledge on electronics probably creats the most of my problems. i have allready finished with the rest of my project but now i want to sent a string of 24 chars with ultrasounds from one port from my arduino mega and receive it to an other.

i have fount this schematics over internet and i have connected trancmiter to pin 7 and receiver to pin 8

analogRead on the receiver gives me nothing. ither i am doing something wrong or i cand drive the transmiter !

first of all is something like that going to work ?
should i play with pwm of the transmiter and receiver ports while both works under 40khz ? and if yes, HOW ?
digitalRead and write or analogRead and Write ?

Please help !

robtillaart

Quote
i have allready finished with the rest of my project

if so, can you post your code to see what is wrong with it?

Q: how do you measure incoming bursts? interrupt driven or ?
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

kourpetis

i allready did over there too ! my problem is that i don't know where the problem is ! so i am showing the schematics that i am using ! the rest of the code is creating a string of 24 chars for sure, i get it clearly to my screen with serial communication.

now how am i going to transmit and recieve 24 chars with ultrasounds ! that is my problem ! does the schematics look good to you ? and if they are ! do you thing that i should play with pwm to the ports ? i am more like thinging to create two functions for high and for low and then a table for each letter that will have high and lows acordingly. then after char recognition to start all those highs and lows ogether on th transmiter.

the thing is that when i try serial read on reciever i get the same numbers ( around 350 ) EVEN IF I DISCONECT THE WIRE FROM THE RECIEVER PORT  !!!!!!!!!!!!!!!!!!!!!! this is why i don't know what is goin wrong ! and how am i going to fix it !

Thanks for your quick responce
Kourpetis Athanasios

CrossRoads

I can't see you getting much of a signal from an unpowered receiver like that.
You need something to amplify the output into a good enough 1 when it shows up at the input pin.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

kourpetis

do you think that normal sound amplifier would do the job ?

CrossRoads

Sure. You want a signal from 0-0.5V for a Low and 3.5-5V for a High.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

kourpetis

so should i amplify both transmiter and receiver ?

CrossRoads

T1 acts as the amplifier for the transmitter.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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