433 Mhz transmitter/receiver

Thread Starter

allenpitts

Joined Feb 26, 2011
153
Hello AAC Wireless forum,

Have developed a devise with a sail that runs up a kite string, drops a payload,
and releases the sail so the device (called a Messenger) can run back down
the kite string and the process can be repeated with a new payload.

A Top Race Drone Clip Remote Control Object Launcher
https://www.amazon.com/Top-Race-Lau...hvlocphy=&hvtargid=pla-4584070138255163&psc=1
was adapted to the Messenger. It has been tested and works
reliably to about 150 yards.

There is some interest in the Messenger at several kite shops.
It would be good to develop the electronics in-house so
the radio transmitter/receiver would not have to be purchased
from Top Race. Also have a PCB shop and a 3D printing manufacturer
that could make the device custom designed for the Messenger.

A search was done. Almost all the DYI transmitter/receiver pairs
found used the Arduino microcontroller. Would like to avoid the space
and cost of the Arduino if possible. Found a radio transmitter/receiver
based on a 555 timer at

The transmitter/receiver pair was bought thru Amazon:
https://www.amazon.com/dp/B07PDGKW8B?psc=1&ref=ppx_yo2_dt_b_product_details

Based on a study of the YouTube two schematics were drafted:
Transmitter_w_555_schematic.gif

Receiver_w_IRFZ44_schematic_800_x_600.gif

The schematics are breadboarded but LED D1 is not reacting.

Not sure if the rules of the forum prevent more than one question per
post. If so, the questions will be separated into individual posts.

Question 1. Do the schematics make sense? Is there a defect
in the device found in the YouTube video and the schematics copied
herewith?

Question 2. Are there existing schematics for tested radio transmitter/receivers?
If there are, the a defect in the conversion of the device in the YouTube to
schematics drawn by me may might be avoided.

Question 3. The 433 Mhz transmitter/receiver pair purchased
on Amazon has a place on the transmitter for an antenna.
There does not seem to be a place on the receiver for an antenna.
Would not the receiver need an antenna, not a transmitter?

Thanks.

Allen Pitts, Dallas TX

Troubleshooting Circuit Tests
Transmitter Tests

T1. 555: Pins 4 & 8: 12.3 volts
T2. 555: Pin 3 and R1.1: 5.0 volts
T3. R1.2: 2.7 volts
T4. 555: Pin 4: 12.3 volts
T5. 555: Pin 6 & R3.1: 5.6 volts
T6. 555: Pins 3.2: 5.4 volts
T7. R2.1: 5.4 volts
T8. R2.2: 12.3 volts
T9. 555: Pins 8: 12.3 volts
T10. Transmitter Vcc: 12.3 volts
T11. Transmitter Grnd: 12.3 volts
T12. Transmitter Data: 2.7 volts

Receiver Tests
R1. Q1 Gate: 5.1 volts
R2. Q1 Data: 0 volts
R3. Q1 Grnd: 5.1 volts
R4. R2.1: 1.9 volts
R5. R2.2: 5.1 volts
R6. LED anode: 0 volts
R7. LED cathode: .7 volts
R8. Receiver Vcc: .7 volts
R9. Receiver Data: 1.9 volts
R10. Receiver Vcc:: 5.1 volts
 

KeithWalker

Joined Jul 10, 2017
2,045
What is the function of the IRFZ44 in the receiver circuit? It needs more than 4V gate to source voltage before it will even start to conduct. This graph is copied from the data sheet:
IRFZ44.jpg
 

Thread Starter

allenpitts

Joined Feb 26, 2011
153
Hello AlbertHall, KeithWalker and the AAC RF form,

The feedback is appreciated.

Have altered the breadboard using this schematic:
Receiver_w_IRFZ44_schematic_800_x_600.gif

Some progress is made because the LED comes on for one second when the receiver is first fed 5 volts. However,
when the transmitter is fed 12 volts (if the operation of the system is understood correctly) D1 should light for as
long as S1 is closed.

Have tried opening and closing S1 with no change.

By accident it was noted that when the receiver module was removed from the breadboard, for photography, D1 came on and remained on.

These are photos of the transmitter and receiver modules:
Transmitter_receiver_photo_211023.png

Back of receiver:

Receiver_photo_2.jpg

Back of transmitter:
Transmitter_back_photo.jpg

Front of receiver. Antenna pad?
Receiver_photo.jpg

Question 1. There is sincere gratitude for the help in the progress made, but the transmitter does not seem to be operating the receiver. Will rerun the tests listed after the first post and relist if there are differences.

Question 2. At the YouTube video (in first post marked 'Remonte Control' [sic]) there are comments from folks who are having trouble making this work. Have tried reaching out to the YouTube publisher, inventor_KR. It is clear that English is his second language at best and inventor_KR is unable to respond to inquiries in intelligible English.
The transmitter/receiver modules are inexpensive PCBs also of foreign origin, probably Chinese. Considering ordering another set of PCBs in the hopes, if the WayinTop PCBs cannot be made operational, PCBs by Devmo can be substituted using the the existing schematics.
Amazon.com: DEVMO 433MHz Ask Wireless Remote Control Transmitter and Receiver Module Kit STX882+SRX882 with Copper Spring Antenna : Electronics
It looks like this system is similar to systems operating garage door openers, radio controlled drones, cars, boats & planes and Top Race Drone Clip Remote Control Object Launcher
https://www.amazon.com/Top-Race-Lau...hvlocphy=&hvtargid=pla-4584070138255163&psc=1
Has anyone ever done this before using the WayinTop (or similar) systems? Has anyone ever done this before in general?

Question 3. Perhaps the fact that there seems to be a defect in the antenna placement in the WayinTop system maybe indicates that the system is basically flawed. For instance, the Devmo system referenced in the Amazon URL above comes with two spring antennas and a place on the receiver marked 'ant'.

Please accept my sincere gratitude for the feedback, especially from AlbertHall. There is an aspiration that some reciprocity could transmitted for the knowledge and experience granted. Maybe, if the Messenger is marketable, a percent of sales would be appropriate.

Thanks.

Allen Carr Pitts, Dallas Texas

PS Here are some screenshots of the systems from the YouTube video 'Remonte Control'

Transmitter. Pin 8 is connected to Pin 4 on the back of the 555 as Pin 2 is connected to Pin 6, visibly here, on the front.
433_RF_w_555_555_hookup_211019.gif

Receiver:
Photo_Receiver_211023.gif
 

AlbertHall

Joined Jun 4, 2014
11,610
when the receiver is first fed 5 volts
Is the receiver to run from 3.7V as in the diagram or 5V as in your later post?
Especially if it will be 3.7V then you will need a logic level MOSFET.

I believe the receiver antenna pad is the one right in the corner by the coil.
 

BobTPH

Joined Jun 5, 2013
4,051
You cannot use that pair as a simple on / off remote. There is a lot of interference in that channel. You will get false triggers all the time. To make it work you need a micro or a special chip used by remotes on each side. The work by sending a known string if bits.

Bob
 

KeithWalker

Joined Jul 10, 2017
2,045
Hello AlbertHall, KeithWalker and the AAC RF form,

The feedback is appreciated.

Have altered the breadboard using this schematic:
View attachment 250906

Some progress is made because the LED comes on for one second when the receiver is first fed 5 volts. However,
when the transmitter is fed 12 volts (if the operation of the system is understood correctly) D1 should light for as
long as S1 is closed.

Have tried opening and closing S1 with no change.

The IRFZ44 will never switch on because the signal voltage output from the receiver is too low. The MOSFET needs at least 4V to even start conducting. A better choice would be a NPN transistor, e.g. 2N3904.
The receiver output will be a square wave with a frequency in the audio range. If you have limited test equipment, you could check the output by connecting high impedance headphones across the LED.
 

Thread Starter

allenpitts

Joined Feb 26, 2011
153
Hello Albert Hall, BobTPH, Keith Walker and the AAC RF forum,

Tried substituting the 2N3904 for the IRFZ44n:

2N3904 emitter at previous IRFZ44n source
2N3904 base at previous IRFZ44n gate
2N3904 collector at previous IRFZ44n drain

expected result: when receiver fed 5 volts and transmitter fed 12 volts, D1 at receiver lights
actual result: when receiver fed 5 volts D1 lights and stays on
when transmitter fed 12 volts no change

Is there a system that will operate the EFLA405 Servoless Payload Release?
https://www.amazon.com/E-flite-EFLA405-Servoless-Payload-Release/dp/B00CPNA52I

Thanks

Allen Pitts,
 

AlbertHall

Joined Jun 4, 2014
11,610
actual result: when receiver fed 5 volts D1 lights and stays on
Try connecting a 10k resistor from the base of the transistor to GND.
We don't know the specification of the voltage output from the receiver and its low voltage may be more than the base emitter turn on voltage of the transistor.
If you have a meter you could measure the receiver output voltage with the button pressed and not pressed.
 

Thread Starter

allenpitts

Joined Feb 26, 2011
153
Hello Keith Walker and the AAC RF forum,

Tried connecting 10k ohms between the 2N3904 base and ground.
The only observable difference is D1, which previously would come on for 1 second and go off,
would not come on at all.
Also tried replacing the 2N3904n with IRFZ44n and putting the 10k ohms between the IRFZ44n gate and ground.
Same result.

Have no means of checking to see if the transmitter is actually transmitting a square wave modulated RF signal.
It is supposed that to check that would require an oscillator at the transmitter out put. I have a digital multimeter but no oscillator.
Access is available to an oscillator at an electronics lab called Dallas Makerspace but not sure how to use an oscillator.

It seems somebody has done this or similar: a single channel radio transmitter receiver sending a set signal for a hundred yards. Pretty sure garage door openers, radio controlled drones, cars, boats & planes use a similar system. And in fact, drones, cars, planes and boats use multi-channel systems for multiple controls.

Have looked at
Amazon.com: DEVMO 433MHz Ask Wireless Remote Control Transmitter and Receiver Module Kit STX882+SRX882 with Copper Spring Antenna : Electronics
but this requires input for the transmitter and out put for the receiver (I think) and have no idea how hook it up.
Have even purchased, received and played with
Mini Relay Wireless Switch 12V 433Mhz Remote Control Relay Switch, Secure 1-Channel Micro Receiver with Transmitter System in Latched Mode DC 3.7V 5V 6V 7V 9V 12V - - Amazon.com
but besides being a latch switch instead of momentary switch, the system received and tested, sends as signal from the fob to the receiver, as indicated by an LED on the receiver, but is not successful in getting the receiver to operate a devise outside the receiver like a resistor w LED.

Will continue to look. Any ideas would be appreciated.

Thanks.

Allen in Dallas
 

Yaakov

Joined Jan 27, 2019
3,755
Overkill for sure, but I am on IOT mode lately, so I might do the same.

Bob
The funny thing is, in this case it's really hard to call it overkill. ESP8266s are cheap as dirt, the code is at least 80% written in libraries, and the reliability is probably much higher than the cheap 433MHz ASK boards.

You could also expand functionality, including using a (bigger, somewhat more expensive) ESP32 CAM board to stream video or shoot stills. But, even without the it's probably not more expensive in parts than the current direction and the effort isn't really a lot more.
 

mar10

Joined Mar 23, 2019
67
I think ESP8266 might have an issue with "It has been tested and works reliably to about 150 yards"
Maybe with a directional antenna at the foot of the kite-line... But more tricky.
But yes, ESP8266 is very useful for a lot of stuff.
 

Yaakov

Joined Jan 27, 2019
3,755
I think ESP8266 might have an issue with "It has been tested and works reliably to about 150 yards"
Maybe with a directional antenna at the foot of the kite-line... But more tricky.
But yes, ESP8266 is very useful for a lot of stuff.
I would be exceedingly surprised if an ESP8266 could not do line of sight operation well in excess of 150 yards. If I get a chance, I will test it.
 

mar10

Joined Mar 23, 2019
67
Then remember to find the smallest gain of both the access point and the ESP.
Since if you are not designing for any direction, the worst case should be considered.
If not, we end up with the directional antenna advice.
Which, for the record might also apply to the 443MHz case if you are not picking the right antennas.
And thinking of this, since we have a rapidly moving target, the wifi might have some issue tuning when you need it in the split second you arrive up there... Remember, it is not a mobile technology, it is wireless.
 

Thread Starter

allenpitts

Joined Feb 26, 2011
153
AlbertHall, KeithWalker, Yaakov, BobTPH and the AAC RF form,

Found a system that works in preliminary tests

QIACHIP 433MHz Universal Wireless RF Remote Control Switch DC 6V 12V 24V 1CH Channel Relay Wireless
Secure RF Remote Control Switches Transmitter and Receiver kit, Momentary Toggle Latched Delay Mode
QIAchip 433Mhz Universal Wireless RF Remote

Have tested using this hookupMessenger_hookup_schematic_211028_600_x_400.gif
The next step is to test it with the Servoless Payload Release.
EFLA405_211028_c.gif

There was a suggestion that an ESP8266 be used with a smart phone. Have not been able to find the
dimensions of the ESP8266 but it seems to be much larger than the QIACHIP system. The system needs
to fit
Kite_messenger_w_sail_210731.jpg
in the element of the Messenger marked 'Rear'. The QIACHIP PCB is 10mm by 25 mm and the batteries
and the EFLA405 all have to fit in the 'Rear' element.

Thanks to all who replied.

Allen Pitts, Dallas TX
 
Top