Sonsivri

Good evening.
I´m trying to establish a link between 2 microcontrollers (PIC 12F508), using cheap RF modules (Those used with arduino), and bought 2 kinds of them.... a FS1000A with its receiver and a WL102 341 (superheterodyne) with its receiver.
I know... a lot of people will strt yelling "USE AN ADVANCED MICRO, WITH AN UART!!!!"... and I´ll agree with all of them... but I only have 15 x pic 12F508... so, it is the one that I´ll use.
Best of all, I was able, (with de FS1000 couple), to interconnect 2 protoboards till 3m distance, and using 3 different on/off switches with the transmitter, and 3 different leds in the receiver.
I have to recgnize that I don´t know even a little about radio transmission, only the use of a carrier frequency, and the ASK/OOK protocol which simplifies the data transmission. That´s all.
So, with this equipment, started to try different frequencies of data transmission over that carrier, using the NEC (infrarred led remote control) protocol, and IT WORKED with the FS1000 couple, on a distance up to 3m... Then, when trying to enhance this, stopped working and never connected again... Well, I have 3 couples of each pair, and tried to make it work again, and nothing... So I decided to use the WL102 couple... and worst... Not started even once.
As a try, I conected microcontrollers directly, to evaluate discrepancies between emitter and receiver programs (frequencies, etc), and all was ok, so I discarded problems with the programming step. Of course, there is always a variable, which is the time lenght of each transmitted pulse, wich can affect the performance of the couple, and I´m testing this right now... But just in case any of you had tried this before, and have a suggestion (besides the UART thing), I´ll accept and thank any one.
I´m trying to make it work with 3.3V, and later use higher voltage on the module that accept this.
Of course... you´ll tell me "just buy some TX/RX devices from amazon for a couple of bucks"... and yes, if I were in a first world country, I´ll just don´t even hesitate in doing that... but here, in the 6th world, I have to buy one of those (for only one channel) in around U$S24.50... which is a robbery...
So, thanks in advance.
Regards.

Most probably your problem is the level difference between 3,3V logic and 5V logic.

Check the following link and try to make or buy similar circuit.
https://www.sparkfun.com/products/12009
You can look for also some simple solutions made by some resistors and transistor also. There are a lot in internet.

https://www.google.com/imgres?imgurl=https%3A%2F%2Fwww.gadgetronicx.com%2Flogic-level-converter-5v-3-3v%2Fvoltage-level-converter%2F&imgrefurl=https%3A%2F%2Fwww.gadgetronicx.com%2Flogic-level-converter-5v-3-3v%2F&tbnid=F2Q_htzDGnnvWM&vet=12ahUKEwi5_onIjb_8AhXUxwIHHfI-CdwQMygEegUIARCaAQ..i&docid=9XrSXhdD3afswM&w=768&h=629&q=level%20converter%205v%20to%203.3v&ved=2ahUKEwi5_onIjb_8AhXUxwIHHfI-CdwQMygEegUIARCaAQ

Ero

FS1000A module TX works on a wide voltage 2.5v to 12v, but even for testing use the module on the same voltage used for the interfacing microcontroller. (5V) But the same gives best range on 9-12 volts . On the Receiver module, 5v is mandatory.

Hi Poty,

here is some advices using cheap RF modules.

http://www.romanblack.com/RF/cheapRFmodules.htm (http://www.romanblack.com/RF/cheapRFmodules.htm)

Best regards.

I have used the HC-12 module with great success.
It is an RTX with more than 100 channels and can be programmed with AT commands.

https://it.aliexpress.com/item/32805756453.html?pdp_npi=2%40dis%21EUR%212%2C52%E2%82%AC%212%2C09%E2%82%AC%21%21%21%21%21%40211b80c216843454258023950e0001%2112000031355642123%21btf&_t=pvid%3A7dd7e899-0413-4d2f-8dfc-c65141c8ee34&afTraceInfo=32805756453__pc__pcBridgePPC__xxxxxx__1684345426&spm=a2g0o.ppclist.product.mainProduct&gatewayAdapt=glo2ita

Thanks for you suggestion. I was checking it on Ali Express, and seems to be a nice RTX, but looking for it in here, in this country, the price is crazy.... Almost U$S 50 Each one.. Not a good medicine...
Besides that, what are for those parameters following the URL of Ali Express and the ht12 (marked in red)?

https://it.aliexpress.com/item/32805756453.html?pdp_npi=2%40dis%21EUR%212%2C52%E2%82%AC%212%2C09%E2%82%AC%21%21%21%21%21%40211b80c216843454258023950e0001%2112000031355642123%21btf&_t=pvid%3A7dd7e899-0413-4d2f-8dfc-c65141c8ee34&afTraceInfo=32805756453__pc__pcBridgePPC__xxxxxx__1684345426&spm=a2g0o.ppclist.product.mainProduct&gatewayAdapt=glo2ita

Sorry if my reply is out of topic but I think this could help solve your problem.

I gave up with the common 433 MHz or 325 MHz modules and now solely use NRF24L01 modules from ebay or such.
I find NRF24L01 are cheap and give awesome range with ease of application.

Also look for NRF24L01 plus SMA Antenna 2.4 GHz 1100M & NRX6M2 you can find all 3 for very little money.

Nice suggestions! NRF24L01 is a pretty effective RTx... In fact, I have 4 modules, 2 with SMA antenna, and 2 with onboard ones. But I didn´t tell you all the story. I´m trying to make those work with a PIC12F508, which has only 8 pins... and NRF needs 4 or 5... which make it unusable in this project. It is intended to make a remote control from one TX to multiple RX, and then command lights, or whatever I want... and using NEC protocol. In fact, I made it work until 3m(10ft) distance... But I want more distance, to make something really useful...
Regards.

With the CE and CS line tied to the supply, you only need 3 pins to control SCK, MISO and MOSI lines.
12F508 should be able to control this, I think.
This I have not yet tried so I might be wrong.

I agree, but there is another issue.... program memory.. 12F508 is almost the smaller one that you can get on 12F series.... Anyways, I´ll try. Thank you.

Looking through my past work, I found that rather than standard serial transmission, I tend to use a modified Manchester coding to carry the signal across with an old 315 MHz transmitter and receiver.

I used 15ms of high signal as a "1" and 5ms as "0" and read the code at 10ms time slot.

I would send $AA as preamble then a series of codes to ensure that the right transmitter goes to the right receiver.
Then a short payload of not more than 10 bytes.