Hello to the group,

I just found this forum and hopefully, I can learn some more about
homebrewing stuff. I have been a hobbyist in electronics for a little over a
year now and recently received my element 2 tech license. Last year I built
an infrared transmitter and receiver pair to trigger my camera remotely
(about a 50 foot range). Since then, I have wanted to do the same thing with
RF. I have a tek465b oscilloscope and a dmm, and have built some of my own
test equipment (square wave signal generator, power supply, battery tester)
and lots of timer circuits with 555's and cd 4060s. Recently I have been
experimenting with audio and ultrasound with opamps. All of my projects are
battery operated.

I recently bought the Velleman RX 433 and TX 433 modules to try and remotely
control my camera. Each module has a 'data' pin, the receiver also has a
linear pin, which I am not sure how to use yet. I have been reading the data
sheets and app note on the velleman site and it shows something called a
HT12E being used to generate the data on the TX module and a HT12D to use
these modules for remote control. I googled for the HT12E and it says it is
a LSI encoder and you need the HT12D as the matching decoder (on the
receiver). Not being familiar with all the terminology yet, I am wondering
why I couldn't just generate a square wave to the data pin of the TX
module, and, then, at the receiver, use a divide down counter to make sure
enough pulses arrived, and then trigger my relay. Does anyone know if this
will work? or would it just be easier (and maybe more reliable) to use the
HT encoder and decoder?

I am asking because I am not familiar with the type of waveform or pulse
shape that the Holtek generates, and, I am not sure if I just want to try
pushing a 555 type square wave thru my TX unit and maybe end up letting the
smoke out.

Any suggestions or ideas are appreciated.

TIA,
Joe
KB1KVI

Hi Joe,
IMHO the linear output of the RX is for testing purposes, you should
let it unused. The encoder/decoder pair is used as a key-and-lock, for
better reliability and security. Your solution using a pulse generator
at the TX side might do for a camera remote control - it can be less
safe than, say, a car alarm. A bandpass filter or a PLL checking the
frequency of the pulses on the receiver output should work even better
than a counter only.
The TX unit has limits for input voltage and frequency. If you do not
exceed them, no damage should take place.

BR from Ivan

"Joe" wrote in message hlink.net...
Hello to the group,

I just found this forum and hopefully, I can learn some more about
homebrewing stuff. I have been a hobbyist in electronics for a little over a
year now and recently received my element 2 tech license. Last year I built
an infrared transmitter and receiver pair to trigger my camera remotely
(about a 50 foot range). Since then, I have wanted to do the same thing with
RF. I have a tek465b oscilloscope and a dmm, and have built some of my own
test equipment (square wave signal generator, power supply, battery tester)
and lots of timer circuits with 555's and cd 4060s. Recently I have been
experimenting with audio and ultrasound with opamps. All of my projects are
battery operated.

I recently bought the Velleman RX 433 and TX 433 modules to try and remotely
control my camera. Each module has a 'data' pin, the receiver also has a
linear pin, which I am not sure how to use yet. I have been reading the data
sheets and app note on the velleman site and it shows something called a
HT12E being used to generate the data on the TX module and a HT12D to use
these modules for remote control. I googled for the HT12E and it says it is
a LSI encoder and you need the HT12D as the matching decoder (on the
receiver). Not being familiar with all the terminology yet, I am wondering
why I couldn't just generate a square wave to the data pin of the TX
module, and, then, at the receiver, use a divide down counter to make sure
enough pulses arrived, and then trigger my relay. Does anyone know if this
will work? or would it just be easier (and maybe more reliable) to use the
HT encoder and decoder?

I am asking because I am not familiar with the type of waveform or pulse
shape that the Holtek generates, and, I am not sure if I just want to try
pushing a 555 type square wave thru my TX unit and maybe end up letting the
smoke out.

Any suggestions or ideas are appreciated.

TIA,
Joe
KB1KVI

Hi Joe,
IMHO the linear output of the RX is for testing purposes, you should
let it unused. The encoder/decoder pair is used as a key-and-lock, for
better reliability and security. Your solution using a pulse generator
at the TX side might do for a camera remote control - it can be less
safe than, say, a car alarm. A bandpass filter or a PLL checking the
frequency of the pulses on the receiver output should work even better
than a counter only.
The TX unit has limits for input voltage and frequency. If you do not
exceed them, no damage should take place.

BR from Ivan

"Joe" wrote in message hlink.net...
Hello to the group,

I just found this forum and hopefully, I can learn some more about
homebrewing stuff. I have been a hobbyist in electronics for a little over a
year now and recently received my element 2 tech license. Last year I built
an infrared transmitter and receiver pair to trigger my camera remotely
(about a 50 foot range). Since then, I have wanted to do the same thing with
RF. I have a tek465b oscilloscope and a dmm, and have built some of my own
test equipment (square wave signal generator, power supply, battery tester)
and lots of timer circuits with 555's and cd 4060s. Recently I have been
experimenting with audio and ultrasound with opamps. All of my projects are
battery operated.

I recently bought the Velleman RX 433 and TX 433 modules to try and remotely
control my camera. Each module has a 'data' pin, the receiver also has a
linear pin, which I am not sure how to use yet. I have been reading the data
sheets and app note on the velleman site and it shows something called a
HT12E being used to generate the data on the TX module and a HT12D to use
these modules for remote control. I googled for the HT12E and it says it is
a LSI encoder and you need the HT12D as the matching decoder (on the
receiver). Not being familiar with all the terminology yet, I am wondering
why I couldn't just generate a square wave to the data pin of the TX
module, and, then, at the receiver, use a divide down counter to make sure
enough pulses arrived, and then trigger my relay. Does anyone know if this
will work? or would it just be easier (and maybe more reliable) to use the
HT encoder and decoder?

I am asking because I am not familiar with the type of waveform or pulse
shape that the Holtek generates, and, I am not sure if I just want to try
pushing a 555 type square wave thru my TX unit and maybe end up letting the
smoke out.

Any suggestions or ideas are appreciated.

TIA,
Joe
KB1KVI

"OK1SIP" wrote in message
om...
Hi Joe,
IMHO the linear output of the RX is for testing purposes, you should
let it unused. The encoder/decoder pair is used as a key-and-lock, for
better reliability and security. Your solution using a pulse generator
at the TX side might do for a camera remote control - it can be less
safe than, say, a car alarm. A bandpass filter or a PLL checking the
frequency of the pulses on the receiver output should work even better
than a counter only.
The TX unit has limits for input voltage and frequency. If you do not
exceed them, no damage should take place.

BR from Ivan

Hi BR,

Thank you for the info. Today I connected the transmitter data pin to my
square wave generator with a 1Khz square wave (at 3V peak) and I could see
it on the receiver output pins, both the linear and digital pins on the
receiver output pretty much the same signal. The only thing I was confused
about is that, when I first switch the receiver on, the digital output is
quiet (it goes to 5volts at first and then drops to and stays at zero
volts). Once I transmit the square wave to it and turn the transmitter off,
the digital output is very noisy (low frequency, I think) and never settles
back to zero. The linear line comes up to about 2 volts on power up, shows a
pretty good square wave when the transmitter is on and then goes back to the
2 volt level when the transmitter is turned off and stays much quieter.

I can probly filter out the noise on the digital line, or capacitively
couple the linear line to get rid of the dc, but I still need to study this
more. The range was amazing! I measured about 60 feet (~20meters) and the
signal was still strong. This was with the receiver in a building and the
transmitter outside. I can still get more range out of it I am sure, so I
will be testing that also.

I have never worked with phase lock loops before, but I do have a few in my
cmos collection, along with the data sheets. Do you know of any links I can
visit to see some applications of the cd4046B PLL?

Thanks,
Joe
KB1KVI

"OK1SIP" wrote in message
om...
Hi Joe,
IMHO the linear output of the RX is for testing purposes, you should
let it unused. The encoder/decoder pair is used as a key-and-lock, for
better reliability and security. Your solution using a pulse generator
at the TX side might do for a camera remote control - it can be less
safe than, say, a car alarm. A bandpass filter or a PLL checking the
frequency of the pulses on the receiver output should work even better
than a counter only.
The TX unit has limits for input voltage and frequency. If you do not
exceed them, no damage should take place.

BR from Ivan

Hi BR,

Thank you for the info. Today I connected the transmitter data pin to my
square wave generator with a 1Khz square wave (at 3V peak) and I could see
it on the receiver output pins, both the linear and digital pins on the
receiver output pretty much the same signal. The only thing I was confused
about is that, when I first switch the receiver on, the digital output is
quiet (it goes to 5volts at first and then drops to and stays at zero
volts). Once I transmit the square wave to it and turn the transmitter off,
the digital output is very noisy (low frequency, I think) and never settles
back to zero. The linear line comes up to about 2 volts on power up, shows a
pretty good square wave when the transmitter is on and then goes back to the
2 volt level when the transmitter is turned off and stays much quieter.

I can probly filter out the noise on the digital line, or capacitively
couple the linear line to get rid of the dc, but I still need to study this
more. The range was amazing! I measured about 60 feet (~20meters) and the
signal was still strong. This was with the receiver in a building and the
transmitter outside. I can still get more range out of it I am sure, so I
will be testing that also.

I have never worked with phase lock loops before, but I do have a few in my
cmos collection, along with the data sheets. Do you know of any links I can
visit to see some applications of the cd4046B PLL?

Thanks,
Joe
KB1KVI

Hi Joe,
the receiver is probably a superregen type. Superregens are very noisy
with no carrier on their input. Superhet modules reduce the noise
problems, but they are more expensive and complicated.
I worked enough with 4046, but I have no link at hand. It comprises a
VCO and two phase comparators - you use only one of them. What I
remember:
1/ Set the tuning range of the VCO as necessary - not too wide, not
too narrow. Two resistors and a capacitor affect both the the central
frequency and the sweep. Check the tuning range with the loop open and
a variable control voltage applied.
2/ I always used the phase comparator No.2. The comparator No.1 (a XOR
gate in fact) usually did not give me satisfying results.
3/ The filter between the phase comparator output and the VCO control
input is essential for the dynamics of the PLL. Do not underestimate
its design.
IMHO for your purpose you should set the central frequency to the
frequency of the 555 at the transmitting side and a very narrow sweep.
If the proper signal is received, the PLL locks, which is indicated on
one of the 4046 pins. This is your "activated" signal. Otherwise the
VCO runs freely and the loop stays unlocked.

Ivan OK1SIP




"Joe" wrote in message thlink.net...
Thank you for the info. Today I connected the transmitter data pin to my
square wave generator with a 1Khz square wave (at 3V peak) and I could see
it on the receiver output pins, both the linear and digital pins on the
receiver output pretty much the same signal. The only thing I was confused
about is that, when I first switch the receiver on, the digital output is
quiet (it goes to 5volts at first and then drops to and stays at zero
volts). Once I transmit the square wave to it and turn the transmitter off,
the digital output is very noisy (low frequency, I think) and never settles
back to zero. The linear line comes up to about 2 volts on power up, shows a
pretty good square wave when the transmitter is on and then goes back to the
2 volt level when the transmitter is turned off and stays much quieter.

I can probly filter out the noise on the digital line, or capacitively
couple the linear line to get rid of the dc, but I still need to study this
more. The range was amazing! I measured about 60 feet (~20meters) and the
signal was still strong. This was with the receiver in a building and the
transmitter outside. I can still get more range out of it I am sure, so I
will be testing that also.

I have never worked with phase lock loops before, but I do have a few in my
cmos collection, along with the data sheets. Do you know of any links I can
visit to see some applications of the cd4046B PLL?

Thanks,
Joe
KB1KVI

Hi Joe,
the receiver is probably a superregen type. Superregens are very noisy
with no carrier on their input. Superhet modules reduce the noise
problems, but they are more expensive and complicated.
I worked enough with 4046, but I have no link at hand. It comprises a
VCO and two phase comparators - you use only one of them. What I
remember:
1/ Set the tuning range of the VCO as necessary - not too wide, not
too narrow. Two resistors and a capacitor affect both the the central
frequency and the sweep. Check the tuning range with the loop open and
a variable control voltage applied.
2/ I always used the phase comparator No.2. The comparator No.1 (a XOR
gate in fact) usually did not give me satisfying results.
3/ The filter between the phase comparator output and the VCO control
input is essential for the dynamics of the PLL. Do not underestimate
its design.
IMHO for your purpose you should set the central frequency to the
frequency of the 555 at the transmitting side and a very narrow sweep.
If the proper signal is received, the PLL locks, which is indicated on
one of the 4046 pins. This is your "activated" signal. Otherwise the
VCO runs freely and the loop stays unlocked.

Ivan OK1SIP




"Joe" wrote in message thlink.net...
Thank you for the info. Today I connected the transmitter data pin to my
square wave generator with a 1Khz square wave (at 3V peak) and I could see
it on the receiver output pins, both the linear and digital pins on the
receiver output pretty much the same signal. The only thing I was confused
about is that, when I first switch the receiver on, the digital output is
quiet (it goes to 5volts at first and then drops to and stays at zero
volts). Once I transmit the square wave to it and turn the transmitter off,
the digital output is very noisy (low frequency, I think) and never settles
back to zero. The linear line comes up to about 2 volts on power up, shows a
pretty good square wave when the transmitter is on and then goes back to the
2 volt level when the transmitter is turned off and stays much quieter.

I can probly filter out the noise on the digital line, or capacitively
couple the linear line to get rid of the dc, but I still need to study this
more. The range was amazing! I measured about 60 feet (~20meters) and the
signal was still strong. This was with the receiver in a building and the
transmitter outside. I can still get more range out of it I am sure, so I
will be testing that also.

I have never worked with phase lock loops before, but I do have a few in my
cmos collection, along with the data sheets. Do you know of any links I can
visit to see some applications of the cd4046B PLL?

Thanks,
Joe
KB1KVI

"Joe" wrote in message
hlink.net...

Thank you for the info. Today I connected the transmitter data pin to my
square wave generator with a 1Khz square wave (at 3V peak) and I could see
it on the receiver output pins, both the linear and digital pins on the
receiver output pretty much the same signal. The only thing I was confused
about is that, when I first switch the receiver on, the digital output is
quiet (it goes to 5volts at first and then drops to and stays at zero
volts). Once I transmit the square wave to it and turn the transmitter
off,
the digital output is very noisy (low frequency, I think) and never
settles
back to zero. The linear line comes up to about 2 volts on power up, shows
a
pretty good square wave when the transmitter is on and then goes back to
the
2 volt level when the transmitter is turned off and stays much quieter.

I can probly filter out the noise on the digital line, or capacitively
couple the linear line to get rid of the dc, but I still need to study
this
more. The range was amazing! I measured about 60 feet (~20meters) and the
signal was still strong. This was with the receiver in a building and the
transmitter outside. I can still get more range out of it I am sure, so I
will be testing that also.


Hi, Joe -

I think the linear output is from the detector in the receiver while the
digital output is following an amplifier with AGC (automatic gain control).
If so, then you may find that the linear output will decrease in amplitude
with distance but the digital output will stay constant until the range is
so great that the signal drops into the noise. Using the decoder on the
digital output eliminates the noise you see when the transmitter is off.

Sounds like a fun project.

John

"Joe" wrote in message
hlink.net...

Thank you for the info. Today I connected the transmitter data pin to my
square wave generator with a 1Khz square wave (at 3V peak) and I could see
it on the receiver output pins, both the linear and digital pins on the
receiver output pretty much the same signal. The only thing I was confused
about is that, when I first switch the receiver on, the digital output is
quiet (it goes to 5volts at first and then drops to and stays at zero
volts). Once I transmit the square wave to it and turn the transmitter
off,
the digital output is very noisy (low frequency, I think) and never
settles
back to zero. The linear line comes up to about 2 volts on power up, shows
a
pretty good square wave when the transmitter is on and then goes back to
the
2 volt level when the transmitter is turned off and stays much quieter.

I can probly filter out the noise on the digital line, or capacitively
couple the linear line to get rid of the dc, but I still need to study
this
more. The range was amazing! I measured about 60 feet (~20meters) and the
signal was still strong. This was with the receiver in a building and the
transmitter outside. I can still get more range out of it I am sure, so I
will be testing that also.


Hi, Joe -

I think the linear output is from the detector in the receiver while the
digital output is following an amplifier with AGC (automatic gain control).
If so, then you may find that the linear output will decrease in amplitude
with distance but the digital output will stay constant until the range is
so great that the signal drops into the noise. Using the decoder on the
digital output eliminates the noise you see when the transmitter is off.

Sounds like a fun project.

John

"OK1SIP" wrote in message
om...
Hi Joe,
the receiver is probably a superregen type. Superregens are very noisy
with no carrier on their input. Superhet modules reduce the noise
problems, but they are more expensive and complicated.
I worked enough with 4046, but I have no link at hand. It comprises a
VCO and two phase comparators - you use only one of them. What I
remember:
1/ Set the tuning range of the VCO as necessary - not too wide, not
too narrow. Two resistors and a capacitor affect both the the central
frequency and the sweep. Check the tuning range with the loop open and
a variable control voltage applied.
2/ I always used the phase comparator No.2. The comparator No.1 (a XOR
gate in fact) usually did not give me satisfying results.
3/ The filter between the phase comparator output and the VCO control
input is essential for the dynamics of the PLL. Do not underestimate
its design.
IMHO for your purpose you should set the central frequency to the
frequency of the 555 at the transmitting side and a very narrow sweep.
If the proper signal is received, the PLL locks, which is indicated on
one of the 4046 pins. This is your "activated" signal. Otherwise the
VCO runs freely and the loop stays unlocked.

Ivan OK1SIP




Hello Ivan,

I was just going to use a bandpass filter, but I will probly play around
with the PLL, since I have never used them before. Thanks for the tips.

Joe
KB1KVI