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Old Oct 23, 2003, 12:19 AM
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Diy Am Tx/rx

Why not?

Theres DIY everything else.

I am curious
could the RX2 and TX2 chips be used for AM modulators and demodulators like replacing the IR components from the DIYIR thread with the RX2 and TX2 chips. If not I was thinking of a different way to do some PICing with it.

Imagine if you press left then the rudder turns slow till you let up then it stays at it's current position. YTou press throttle up the motor slowly starts to run faster till you let off the throttle button then it stays at it's current speed till you press throttle up or throttle down.

Another idea was to use the 4 inputs and outputs like as a digital system you have 16 possibilities with 4 digits.
I'm not sure how in normal operation info is encoded but if it is possible to transmit all 4 channels at once then you cold use it like numbers. It could work like this a number gets sent that tels which channel then the next number tells how much to change.
Example 1 means throttle then 8 means it is at half throttle. Then there would be a pause to seperate the next signal. Or you could have 3 numbers transmitted and increase the steps to 32. Not sure if the RX2 TX2 pulse train(is that what you cal it?) is short enough- quick enough.

Then the best idea is to not use the TX2 or RX2 and source some AM modulator demodulator chips like the Phillips FM chip. Then use the stuff allready done in the DIYIR thread. From looking at Nick Lechty's (sp?) RX it seems possible to keep it lightweight.
And from experience with the bitplanes I know the range should be greater than the IR systems presently being used.

How bout it?

Billy
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Old Oct 27, 2003, 07:20 PM
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Billy ,
how would fritz mullers tinny am receiver go driveing a pic ?
i have a copy of the circuit and parts list.

Prolly just leave off the last 2 or 3 transistor stages to drive a pic , as it was used to drive an actuator , so needed more amplification
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Last edited by clipclop; Oct 27, 2003 at 07:23 PM.
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Old Oct 27, 2003, 07:35 PM
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Billy ,
the receiver as shown is only 320mili grams ! , so a super light rx is realy posiable Stewart
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Old Oct 27, 2003, 07:42 PM
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billy , here is a circuit for a simple encoder for the tx , i will have to look for a rf circuit for it -shouldnt be to hard to find a crystal locked circuit?
Stewart
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Old Oct 27, 2003, 07:46 PM
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I have been looking around and found an AM receiver that consists of a diode, resistor,capacitor and a low pass filter.
The transmitters seem to have a signal,carrier, multiplier,and adder. On the schematics of the bitcharger tx it looks as if
there is an RF amp in the tx. Wonder if this could replace the IR LEDs in the IR circuit. Could it be that simple? I was looking for a single chip solution that yoiu just input the carrier, signal ,antennae and power but cant find one yet.

Thanks for the schematics Stewart.

Billy
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Old Oct 27, 2003, 07:51 PM
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The bit charger RF amp looks similar to the left half of the TX schematic.

Billy
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Old Oct 28, 2003, 08:28 PM
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Hi ClipClop,

I had Mr. Muller AM RX Schematics with me a long time back, But I lost that on a HDD crash. Any chance you can mail me the parts list? Thanks a lot! My E-mail is savageuc@yahoo.com

Thanks again,
Uttam
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Old Oct 28, 2003, 10:22 PM
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Uttam,
Email is in the pipeline.
Stewart
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Old Oct 29, 2003, 12:29 AM
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Thanks for the e-mail Stewart! I'm sure all the Transistors are BC547's!
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Old Oct 29, 2003, 12:30 AM
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I'll check and let you know, for sure!

Thanks again
-Uttam
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Old Oct 29, 2003, 01:17 AM
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Uttam,
I think the rx is 27megs , could not see any reference to it
Stewart
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Old Oct 29, 2003, 01:53 AM
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Uttam
just a bit i missed in regards to setting up the Rx re -C2, which has to be chosen at values between 22 and 33pF to produce the best oscillations.
Stewart
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Old Oct 29, 2003, 06:21 PM
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billy,
the left half of the encoder circuit is the oscilators to give the basic mark- space ratio to the 4017 , sorry i took so long to reply
Stewart
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Old Oct 30, 2003, 10:49 AM
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Hi clipclop and all,

If the micro RX is working on the 27 MHz band, I can find TX schematics, I have worked on such a TX (Digital Commander - it was published in American Aircraft Modeller in the 70's). In fact I built a full channel system including the servo electronics (discrete - with 8 transistors)..

Could I have the parts list for the micro RX - at bmutlugil@yahoo.com ? Looks interesting, but I don't know how it would behave under electrical noise from the dc motor. A direct conversion RX could be prone to interference or selectivity problems..

Best regards,

Bulent
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Old Oct 30, 2003, 11:42 AM
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Hi all,

How has Mr Muller Soldered the SMD components onto the board? The Blown up layout indicates parts layout/placement, and the pads, but I don't think these are etched, are they? Any ideas?

Thanks,
-Uttam
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