need hlep on designing reciver. ASAP...

[ECET0purdue]

hello
i know everyone is probly tired of hearing my project problems, but you have helped soo much..even added this community in my acknowledgment page..but i need help on this reciver.. ok i have a freq.  comming in i need a chip or something that will test this freq and if it is a certin freq( one i can chage for differnt values) then it will turn on a relay. Also when the relay has power going to it. it will send power to a chip that will send out a freq....
i attached a picture of what i mean becuase iam not good at writing   but i need any help you can give... at least in parts whise i can find the connections and programming for them. thanks,
glen.

ps i knwo its thanksgiving but i would really appraite your help Happy Holidays
...

View attachment 38018

 

[audioguru2]

Hi Eceto,
You need a radio receiver but you don't say the frequency nor how sensitive it must be.

What's the relay for? You want a voltage to come from the receiver when it detects a transmission, so why can't that voltage actvate the new transmitter directly?
There are ways to activate electronic circuits without touching their power supply, called gating.

You also need a radio transmitter but don't say its frequency nor how powerful it must be.

 

[ECET0purdue]

iam sorry i forgot not everyone can read my mind  

okok..this is not a radio reciver. this is a unit that will turn on the relay when the wire going to the input has the same freq as A (A being equal to any freq. i want to set it to.) The power from the relay will turn on a led but also will be the signal high to another chip that will send out freq B (B being a constant freq which i can set it up to be)

now the circuit can be different ...i just need this operation to happen...

here is a little more detal ..

iam sending say 900hz to this input freq. the chip is set to only accept 955hz. so when i send 955hz  the chip will turn on and trigger the relay which will turn on the led.. the relay will also be the input to another chip that will send say the freq 960hz back ... does this help...now the freq has to be adjustable because i only want one reciver to come on per frq.

say i got 4 of these recivers.
one will turn on if it recives 900hz
and return 940hz

one will turn on if it recives 1000hz
and return 1040hz

one will turn on if it recives 1100hz
and return 1140hz

one will turn on if it recives 1200hz
and return 1240hz

hope this helps...thanks
glen

 

[ECET0purdue]

btw these are just made up freq...i am not sure what freq iam going to use...i got a v/f converter and have not looked what range they use..
cheers

 

[audioguru2]

You can detect tones with an LM567 tone decoder IC. Google says that it is discontinued but only the old metal cased one.
I think your selected frequencies are too close together for it.

 

[ECET0purdue]

ok i can change the frq. but these chips will look for just one freq and then then it matches it will send power out?

 

[audioguru2]

When an LM567 detects a tone that it is adjusted for, then its open-collector output goes low with up to 100mA current sinking ability.

You don't need to turn on and off the power supply of your other circuit, you just use the open-collector output of the LM567 to gate it on and off. ;D 

 

[ECET0purdue]

ok that sounds good...   now any ideal on a chip that can send freq. that is able to be set..

 

[audioguru2]

An LM555 or uA555 can make a square wave. But its odd harmonics are pretty high.
You can filter-out the harmonics with a switched-capacitor lowpass filter IC. ;D

 

[ECET0purdue]

hello,
              i was hopeing you could explain this a llittle better for me...for example how do i adjust it to find a freq. that i want. is it by changing the caps? i attached the pinlay out for that chip.

second i dont know if the square wave would work because on the other end i have a freq. to voltage converter so i can convert the freq to a voltage.  and if you think it will work.  could you post a simple circuit?
thanks
glen

View attachment 38022

 

[ECET0purdue]

ok after reading some more about it i got it...the chip is perfect... but i do need help on the rest..  how would i turn on the led and the other chip using this chip when the output is sinking?
btw thanks for the help

 

[ECET0purdue]

ok after some research on the timer. i found this...which i can also do ....but the question i really need now.....how do i make the timer depended on the lm765  that is what i need a small circuit for?
cheers again

 

[ECET0purdue]

just wanted to make sure this is correct

View attachment 38023

 

[audioguru2]

This datasheet for the 567 tone decoder has much more information such as the limit of the resistance for the frequency-determining pot:
http://www-us6.semiconductors.com/acrobat/datasheets/NE567_SE567_2.pdf

A simple way to make a 555 oscillator saves a resistor:

View attachment 38025

 

[ECET0purdue]

sweet now how would you connect the two? as for what i need it to do...the 555 to come on when the 657 has a matching freq..

 

[audioguru2]

You just look in the datasheets to see what the IC's do and need and add a transistor as an inverter to gate the 555 with its reset input pin 4.

View attachment 38026

 

[ECET0purdue]

thanks soo much....  .... ... ....... .... ... .. .. ..... .

 

[audioguru2]

thanks soo much....

 

[ECET0purdue]

ya....really its almost free.... thanks to free samples