► A
wireless transmitter switching system capable of transmitting to switch a
device hundreds of meters away. One use would be for a water
saving irrigation sensor out in the field to transmit back to a solenoid or
pump to start irrigation. Another one of many possible uses would be for the
transmitter to be connected to a rain sensor circuit that could be positioned
in the direction where most precipitation comes from. This would alert people
when it is about to rain or drizzle. Interested people could have a receiver
that buzzed when the sensor became wet due to rain or drizzle. A different
sounding buzz could sound when the rain stopped.
Hello
Below is some info about a long range transmitter I was hoping to find and have
produced. I have one that may work as it did to a point in some close range
tests. I need to do some further testing. However, I am not sure how reliable
this transmitter and receiver will be. It may need to transmit continuously
when the switch is on. However, I heard that there may be a better way to avoid
continuous transmission and save battery power. Another problem that I have
with the unit is that the signal drops out for a split second on a regular
basis. This would mean that the solenoid or pump would go on and off frequently
and it could wear it out. However, the problem could be overcome with perhaps a
timer chip or capacitor so that the circuit on the receiving end could be made
to not cut out until the signal stopped for at least a couple of seconds. I am
not sure if you have any ideas on this.
Below is a description of the transmitter that I need for an irrigation sensor.
However, bear in mind that it could also be used for a rain or drizzle sensor.
This could be a good community project, where a rain sensor and transmitter
could be positioned in the direction where most precipitation comes from. This
would alert people when it is about to rain or drizzle. When the sensor becomes
wet it could enable people in the community to know when a shower is
approaching if they have a receiver and buzzer. It would be very useful to know
when to shut windows, remove washing from the line or remove other gear outside
that is drying. Often showers come without warning. The transmitter would also
have other practical applications.
I am hoping to use an irrigation sensor to remotely switch a solenoid or pump
perhaps about 300 meters away. For some people it may only be about 50 meters
away and for other people a couple of kilometers. Therefore, a few different
types of transmitters and receivers may be needed if the ones to go a shorter
distance would be significantly cheaper or more reliable than the ones to go a
large distance.
My irrigation sensor that I invented has one simple micro switch and there is
info on it at http://www.advantagein.com/irrigation/
and http://advantagein.com/irrigation/irrigation-informationa.htm
.
The irrigation sensor in the field is only a micro switch connected to balance
arm. It is a switch like at http://www.electusdistribution.com.au/ShowLargephoto.asp?id=4158&IMAGE=
where the irrigation can be switched off and remains off when the lever is
pushed down, and it goes on when the pressure on the lever is released and it
goes up. There is no voltage output from my sensor. The switch can be connected
by wires to a solenoid and a power supply. Alternatively, a transmitter could
be connected to the sensor’s switch to transmit to a receiver near a solenoid
or pump. The receiver could be connected to another switch to activate the
solenoid or pump.
A latching relay may not be suitable because the single micro switch at the
receiver end would need to be an exact mirror image of the single micro switch
at the transmitter end. A transmitter would be near the irrigation sensor, and
a receiver would be near the solenoid or pump. When the switch of the
irrigation system closes, I want the switch on the receiver end to also close
and remain closed while the switch on the irrigation sensor is closed. Also,
when the switch on the irrigation sensor opens, I want the switch on the
receiver end to open at the same time. I want the switch on the irrigation
sensor (transmitter end) and the switch at the solenoid (receiver end) to both
remain off until they both go on.
It may be simpler to have a continuous signal transmitted to hold the switch at
the receiving end on, bearing in mind the irrigation system may only be on for
less than half an hour a day. I thought it could add to the complexity and cost
if a separate signal was required to switch the switch on, and then another signal
to switch it off. When the irrigation sensor switch is on, a continuous stream
of signal could be beamed towards the receiver all the time to hold the
solenoid’s switch on. Another small circuit may be needed to avoid short drop
outs, as it would be best to not have the solenoid go off for a short period in
the cycle. Perhaps a timer chip or capacitor could be used so that the solenoid
only goes off if the receiver does not receive the signal for at least a few
seconds.
Perhaps a low cost radio transceiver like the one at http://jaycar.com.au/productView.asp?ID=DC1005&keywords=DC1005&form=KEYWORD
could be used for the remote transmission. I already have one here. Perhaps it
could be simply modified. However, a concern could be that it could interfere
with other devices that people use, and if someone complained it could be a
concern. It would be good if the signal could be beamed in a narrow beam so
that it would only affect the receiver, and the signal would not spread
elsewhere. I thought that this could possibly be done by putting the antenna in
a pipe with possible shielding on the outside, to prevent the signal going
anywhere but in the direction of the receiver. A similar thing could be done
with infrared.
A man in the security system business said “cheap wireless burglar alarm
systems will work about 200 meters away.” I am not sure if one of those
transmitters would be good for people that only need lower transmission ranges.
I am not sure if that could work out cheaper and easier for lower ranges.
Some people mentioned that model aircraft transmitters may a simple affordable
way. However, I am not sure about legalities for my purpose.
Some other possibilities are below.
http://www.siliconchip.com.au/cms/A_30806/article.html . I have the full
article about this that I could show you.
http://www.siliconchip.com.au/cms/A_111077/article.html
http://jaycar.com.au/productView.asp?ID=KC5473&keywords=KC+5473&form=KEYWORD
http://secure.oatleyelectronics.com//product_info.php?cPath=47&products_id=186&osCsid=343a4e6f66d7cd15dc831fc5683cbe53
http://www.ozitronics.com/docs/k175.pdf
http://www.ozitronics.com/docs/k176.pdf
The below two are made up. However, they are more expensive. http://www.elsema.net/proddetail.asp?prod=FMR212T
(Receiver)
http://www.elsema.net/proddetail.asp?prod=FMT312E
(Transmitter)
Please let me know of any suggestions that you have, or if you prefer any of
the above.
I have many other electronic projects which would benefit many people and I
need help to set them up. Please see http://www.advantagein.com/electronics
I also have many websites with new ideas, including separate free groups,
unique inventions with advantages, and rare information with solutions to help
people. Please see http://www.advantagein.com/community.htm
for a brief summary. I would appreciate your feedback and help. Are you
able to swap links or share any letters that I could send you?
My contact details are
below.
Richard
Hole,
Tolga Qld 4882,
Ph 07 4095 5447 within
Email richard(at)truesolutions.info . Note replace (at) with @ and use
electronic as the subject.
Please share this letter with other people and let me know who could help with
any of these ideas. It would be appreciated if you could print it out and
display it. I could also send you some photocopies or a link to a printer
friendly format. I also have this letter as an email that you can share.
Your help would be appreciated
Regards Richard.