Customizable RF frequency Generator and receiver
kowshik1729 last edited by
I would like to know how can we generate RF waves with customizable frequency. For example the generic RF modules which we get in the market operates at a frequency of 433MHz. But I wanna make a transmitter and receiver pair that can operate on freqeuncy that can be customized by me. How can I do it? Please guide me. Thanks in advance..!!
salmanfaris last edited by salmanfaris
This is an interesting question, Traditionally we are using mixers, filters, amplifiers, modulators/demodulators, detectors, etc to build a radio communication system and it's tightly coupled with hardware. And there are many types of frequency modulation like FM, AM, FSK, LoRa etc.
(Source : https://en.wikipedia.org/wiki/Radio)
To generate a different band we need to use a specific combination of mixers, filters, amplifiers, modulators/demodulator, also most of the scenario we only use a specific frequency to communicate in cost-efficient ways like 2.4 GHz for WiFi and Bluetooth but we use different modulations like GFSK in BT Classic and DSSS, FHSS in IEEE802.11 etc. And building many different combinations of mixers, filters, amplifiers are not cost-effective and economic.But using the SDR (Software Defines Radio ) we can achieve this,
A basic SDR system may consist of a personal computer equipped with a sound card, or other analogue-to-digital converter, preceded by some form of RF front end. Significant amounts of signal processing are handed over to the general-purpose processor, rather than being done in special-purpose hardware (electronic circuits). Such a design produces a radio which can receive and transmit widely different radio protocols (sometimes referred to as waveforms) based solely on the software used. (Source: https://en.wikipedia.org/wiki/Software-defined_radio)
So as an answer to your question, yes we can generate radio frequency but it's high cost and not economical, also with the help of the SDR system we can solve the issues.
You can also try SDR via online using https://eshail.batc.org.uk/nb/ , it was hosted at Goonhilly Earth Station in Cornwall, England.
@salmanfaris best if you could point me to an example that works as described: getting different values depending on hoe close the finger is without really touching. nothing i tried did work yet
@salmanfaris I haven't found a good sensor module for this at all. I used a thing which was calles touch sensor and it returns only 1/0. Tried to use touchRead() but it is not sensitive apparently, only 40 and 1 more or less.
#define touch_pin_numer 33
const int VALUE_THRESHOLD = 30;
TOUCH_SENSOR_VALUE = touchRead(touch_pin_numer);
if(TOUCH_SENSOR_VALUE < VALUE_THRESHOLD)
Serial.println ("Touch ON");
Serial.println ("Touch OFF");
should show something between 40 (current max) and 1 (current min) the closer the finger gets but it shows 40/41/39 and 1 - nothing inbetween. got this code from the web
@FlorianB Can you share the code, output window/error and details of the sensor module?
Hi! I am trying to add an capacitive sensor to the ESP32, that will work through glass with 3mm thickness and an distance of 8 to 2 cm. I have bought sensors which only work on touch, i have looked into the touchRead() function but cant get a steady value increase/decrease with distance and only a real touch gets me enough difference to count it as a "touch". I have checked Arduino examples with foil where a resistor can set the sensitivity but nothing worked on my ESP32. i have spent hours looking for an example, can somebody point me to one please?
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