Is it possible to use a Walkie Takie as a transciever?
Microcontrolled
Posts: 2,461
Is there a way? Do you connect your data pin to the mic? (i don't think it is possible to the analog interface created with the mic)
Thanks for the help!
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Thanks for the help!
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Toys are microcontroled.
Robots are microcontroled.
I am microcontroled.
If it's not Parallax then don't even bother. :-)
·
I have changed my avatar so that I will no longer be confused with others who use genaric avatars.
Mini-Din/PS2 connectors are for sale! 5 for $1! PM me if you wish to make an order.
Cheap·shipping unless specified!··········150 left!!··
Comments
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It's Only A Stupid Question If You Have Not Googled It First!!
I don't think I've ever used my radios for talking, only data transmission.
His work is on OBEX.
Ken Gracey
KI6HBT
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Toys are microcontroled.
Robots are microcontroled.
I am microcontroled.
If it's not Parallax then don't even bother. :-)
·
I have changed my avatar so that I will no longer be confused with others who use genaric avatars.
Mini-Din/PS2 connectors are for sale! 5 for $1! PM me if you wish to make an order.
Cheap·shipping unless specified!··········150 left!!··
obex.parallax.com/objects/421/
Is it just me, or is it hard to search the OBEX by author?
Jonathan
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lonesock
Piranha are people too.
Please be sure that data transmission is legal for the radio service you're using. If your walkie talkies use CB, FRS or business frequencies, it probably is not. But if you're a licensed ham using amateur radio frequencies, you're in good shape.
-Phil
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Toys are microcontroled.
Robots are microcontroled.
I am microcontroled.
If it's not Parallax then don't even bother. :-)
·
I have changed my avatar so that I will no longer be confused with others who use genaric avatars.
Mini-Din/PS2 connectors are for sale! 5 for $1! PM me if you wish to make an order.
Cheap·shipping unless specified!··········150 left!!··
http://forums.parallax.com/showthread.php?p=789451
Thanks,
Doug
If so, it's not strictly according to the rules of FRS to do data transmission.
But I seriously doubt that you would ever be called to account on it
Important questions are: do you need a high data rate or not? do you need a one way data channel or a 2way?
If you just need low-rate one-way data, Like remote transmission of temperature, wind speed from a weather station
then I'd send simple tones through the mic circuit on the FRS radio, something like morse would work.
For simplicity, at the receiving end use an ne567 tone decoder chip. It would be a bit kludgy but you could modulate the
FRS by placing a speaker over the mic and driving the speaker from the prop. No need for the FRS to stay on all the time,
drive a relay or switching transistor from the prop to turn the radio on/off.
An easy method if you want full-duplex is to use 4 cheap FRS radios.
FRS really spans 2 UHF bands... chan 1-7 (462.5625-462.7125) and chan 8-14 (467.5625-467.7125)
ch 1 is so far from ch14 that simultaneous transmission/reception using these frequencies should not desense the receivers.
You could also do 2-way data transmission with just 2 FRS radios but you would have to switch each radio from xmit to rcv by using a
switching transistor or optocoupler hooked to a pin of the prop. This might be the way to go as the output transistor in the FRS
radios may not be rated for continuous duty anyway.
If you can find a cheap cordless phone that is not being used any more then you can do full duplex communications from
the handset to the base, and they are rated for continuous duty. The range is not bad either and there is no rule saying you
cannot use them for data transmission. If you make a simple set of external antennas you could get lots of extra range.
You can probably do a google search and turn up info about turning an unused cordless phone into things like point2point data
radios or room bugs..etc
Of course the professional way to do this is to buy ready made modules that are easy to connect to a controller...but I am
assuming you want a low-cost and homemade method.
I agree and this was discussed in detail last year on the Picaxe forum. Here in Australia there are two frequencies allocated for data. However, when you scroll through all the channels on one of those low tech handhelds, it skips the data ones. Voice users would not appreciate having their channels swamped with data, and it is illegal anyway. So essentially, these cheapie hand held units can't be used for data. (even though it is possible technically).
There are lots of other solutions, particularly the 433Mhz data transceiver units from Hope or Yishi or other manufacturers which are a drop-in replacement for a wired RS232 connection and are only around $20 to $30 each. These are <10mW but get a good range by having super sensitive receivers (eg -123db).
Post Edited (Dr_Acula (James Moxham)) : 8/9/2009 2:06:50 AM GMT
An interesting option for VERY long range data is available here in the states.
There is a tiny sliver of bandwidth just below the 20 meter ham band that is available
for use for scientific and educational purposes on a non-exclusive (you can't complain about being interfered with by other users..etc) basis.
13.553-13.567Mhz
If you listen with a quality receiver on CW mode in this band you will hear regular sets of beeps from some
remote gear on 13.5602 .... you will, of course, get reception best during the daylight hours due to the
painful sunspot minimum we are experiencing. The data is from some very weak solar powered remote devices
at various locations across the states. Power output is 1 watt to a simple V ant with apex at just 15ft.
Just this afternoon I had great reception on several of them located at a distance greater than 1,000 miles.
The solar panels that power them are just tiny things about 8 inch square. They are AVR based and the entire
electronics package is about the size of a paperback book.
You need a very narrow bandwidth filter to manage to hear only the signals from these devices because the
frequency range is a mass of various transmissions....bedlam at times.
Post Edited (HollyMinkowski) : 8/9/2009 2:40:26 AM GMT
bands certified for use by a 1st Class FCC license holder....it's not for tinkerers.
I searched on google and came up with a snippet from a page at Google books search.
Note that the 2400Mhz-2500Mhz band has a center freq of 2450Mhz.
That is the freq that was assigned by the FCC for microwave ovens to operate on if I remember correctly...how interesting
And of course, just below 2450 is the wifi band.
The 2,5 and 24Ghz bands would be great for narrow beam width point2point work with small dish antennas.
It is readily apparent that all the wifi bands, cordless phone bands, fall into these allocations.
I find it odd that they put FRS radios on 400mhz and not the 902-928Mhz range already allocated
for such devices...hmmm
What a shame there is not a small bit of spectrum available around 8-10mhz...it would be ideal both
day and night during sunspot minimums unlike 13560 which is only usable during the day...it would not
be as good at longer ranges as 13560 but would be better for shorter ranges. Something around 3Mhz
would be great for 0 to 300 miles.
Post Edited (HollyMinkowski) : 8/9/2009 3:39:01 AM GMT
Seriously, if you are interested in wireless data communication, it's very easy to get an amateur technician class license. You have to pass a test, but it's an easy one. A few evenings study from this book is really all you need to get up to speed. There's no Morse code requirement any more. Then, pick up a pair of used 2-meter handhelds from eBay, and you're all set.
-Phil
With a licence, one could crank up the power over 10mW! And I might need a bit of power once I put Cluso's triblade into my wireless mesh.
-Phil
AD7YF
Ex G8LCU back in the 70's
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Style and grace : Nil point
Post Edited (Toby Seckshund) : 8/9/2009 10:09:55 AM GMT