Developing a digital radio communications circuit design for PCB - Page 1
Forum section: electronics / beginners

author: SanctePieDecime
author_rank: Contributor
timestamp: May 18, 2024, 01:41:07 am
content: So, I am working on a project that will involve transmitting data with a range of about a half mile (and actually I pretty much just need to transmit 1 bit). I am trying to make it all one circuit board. Unfortunately, all the research I have done has been fruitless. All I can seem to find are pre-made modules (such as the HC-12 and NRF24). I would like to know and understand how to design a circuit for the ICs that I keep seeing on these boards so that I can just directly implement the IC in my circuit board without having to use the full module footprint, but I have not been able to find anything. Would anyone be able to point me in the direction of a resource that explains how to accomplish this?

author: Andy Chee
author_rank: Super Contributor
timestamp: May 18, 2024, 02:21:37 am
content: Need more information.Half a mile through water? Air? What about terrain and obstructions?Also what frequency band are you interested in? 3.5MHz? 433MHz? 2.4GHz?Also what do you mean by 1 bit data? I assume you just want a simple on and off function. Which raises the question of data speed, how fast do you want to switch things on and off?If you don't know the answers to any of these, best to stick with using pre-made modules.

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 18, 2024, 02:56:21 am
content: Yes we need to know more about your requirements. First, is this a half mile line of sight, or can there be obstacles, etc.As a very general thought, 2.4GHz RF is not ideal for long range like this unless seriously amplified. Those modules based on a nrf24l01+ can do it in the variant with an added power amplifier, no way they can without this external PA. And even so, they can do it outdoors without obstacles, but will have a hard time otherwise.Given your low throughput requirements and the distance, I would, again as a general recommendation, suggest going for a sub-GHz solution. You have cheap ICs, such as CC1101 or CMT2300A, which should work here. Alternatively, you can go for LoRa, which is much more robust and can cover much longer distances yet. LoRa chips are a bit more expensive.Either way, if you have no prior experience with RF stuff, I'd suggest sticking to pre-made modules rather than implement the RF stage yourself on PCB - it requires some routing care for properly tuning it and is probably not worth the trouble, especially if you're not going to build a lot of these. Modules can be had for a few bucks, guaranteed to work, and some will take very little space on another PCB (like 10x15mm, something like that.)If you're curious, you can still find schematics for some of these modules and see for yourself how they are designed.

author: SanctePieDecime
author_rank: Contributor
timestamp: May 18, 2024, 03:19:50 am
content: My specific application is a mailbox sensor. There are ones that exist but they all tend to rely exclusively on when the door opens and closes and as such I am trying to develop a solution that won't be prone to unnecessary notifications or errors (for instance when you open the mailbox to put mail in).Quote from: Andy Chee on May 18, 2024, 02:21:37 amSo it is just a half-mile through air (so that it could be applied in settings where there are particularly long driveways). I am not terribly worried about terrain but ideally it would not be hindered too much by trees (for instance in an application at a forested home).Quote from: Andy Chee on May 18, 2024, 02:21:37 amThe frequency band doesn't really matter to me as long as it gets the job done. I have not been able to find any resources for integrating any of them directly into a PCB.Quote from: SiliconWizard on May 18, 2024, 02:56:21 amThank you for recommending sub-GHz radio implementation. I should have put more consideration into this, but it makes sense so I am thinking that I would probably want a lower frequency.Quote from: Andy Chee on May 18, 2024, 02:21:37 amThe one bit is just sending the notification to the base station that the mail has been delivered (which is determined through a combination of sensors, comparators, and logic gates). Data speed isn't terribly important, but it will hopefully be fast enough to be able to use the base station to create a log file on an SD card with proper date and time stamps. Then again I will be using a power latch circuit to shut everything down when not in use to conserve battery and as such the faster the transmission is then, theoretically, the more battery can be saved because it would not have to be on as long. But this doesn't really make too much of an impact when considering that the system will have to implement a delay allowing for the mailbox flag position to change after the lid closes in cases of putting mail in the mailbox.Quote from: SiliconWizard on May 18, 2024, 02:56:21 amAs far as not using modules, this is in part so that I can learn how to apply the technology without relying on premade modules (which are in my opinion a little like training wheels). I will definitely start out my testing with premade modules, but I want to move away from them for the final design.

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 18, 2024, 04:49:41 am
content: ebyte is one of the companies making such modules for relatively cheap. They have a web page there in which they describe the design of their SX1262 modules:https://www.ebyte.com/en/new-view-info.html?id=295(The SX1262 from Semtech is one of the "best" LoRa transceiver ICs at the moment.)Note that those modules require some microcontroller, they can't be used "standalone". Unless you already are familiar with some microcontroller you want to use, you can go for some Arduino compatible one, there are already Arduino libraries for the SX1262 (and other LoRa chips) and you'll find various blogs and videos about that.

author: pcprogrammer
author_rank: Super Contributor
timestamp: May 18, 2024, 06:03:13 am
content: Another option is to look into modules liketheseon Aliexpress. No need for a micro on the mailbox side. Just one or more switches connected to the module.Should not be to hard to find what kind of IC's are used on these boards, and make your own PCB using them if wanted. But like some already wrote, with little experience on RF it is best to stick to the pre made modules.On the receiver side use a simple MCU setup to log the received input on your SD card. In the mailbox you can put a switch on the door, the handle or on the bottom to sense mail lying in there.

author: BennoG
author_rank: Frequent Contributor
timestamp: May 18, 2024, 06:19:56 am
content: You also have to consider identification. If the neighbour has the same unit then you will be notified when he gets his mail and also when you get your mail.without knowing what signal is from what mailbox.Benno

author: radiolistener
author_rank: Super Contributor
timestamp: May 18, 2024, 09:17:17 am
content: in your case the most easy solution is just to buy some Chinese remote doorbell and connect it's button to your mailbox sensor.Something like this:https://www.aliexpress.com/item/1005004701032074.html

author: CaptDon
author_rank: Super Contributor
timestamp: May 18, 2024, 01:56:40 pm
content: "Determined through a combination of sensors, logic gates......" Really, the sensing needs to be that complicated, not just a switch that causes the unit to transmit one signal burst? A very simple FM carrier modulated with perhaps a 1KHz tone is all you need for the transmitter. Now it gets complicated. The transmitter requires an antenna that can not be inside the steel mailbox but could perhaps be inside a plastic or fiberglass mailbox. Are you designing this for sale or for your own use?? That will force some hard choices. Also, 1/2 mile is not trivial!! You will most likely be limited to less than 100mw D.C. input power to the R.F. final stage unless the device obtains F.C.C. certification for some of the dedicated remote control frequencies. Also, do you know the part number for the I.C.'s used on the modules?? Why not just Google their datasheets? Based on the probable low transmit power you may require an outdoor directional YAGI antenna which at 2.4GHz are small and practical. I guess you are re-inventing the wheel here as opposed to buying an off the shelf solution. If it is a learning project there must be 100 better ways to learn about R.F. and signalling.

author: tggzzz
author_rank: Super Contributor
timestamp: May 18, 2024, 02:11:55 pm
content: Quote from: SanctePieDecime on May 18, 2024, 01:41:07 amThe phrases you use indicate that you are probably a beginner.Be aware thatdevelopinga radio transmitter isnotsomething a beginner should be attempting. There are too manylegal requirementsto ensure your transmission doesn't screw up someone else with a receiver. Violate any, and you can't complain if neighbours become irate and you are visited by men in black suits.OTOH, it is entirely reasonably tousea module that has already been certified for use in your locality. You will have to verify that any such modules will work over the relevant distances and with relevant power supplies. That ought to be within a beginner's capabilities, and is a very good way ofstartingto learn about RF.

author: radiolistener
author_rank: Super Contributor
timestamp: May 18, 2024, 02:17:05 pm
content: Here is 1 km range intercom, which can be suitable for your needs:https://www.aliexpress.com/item/1005006363485172.html

author: temperance
author_rank: Super Contributor
timestamp: May 18, 2024, 02:21:35 pm
content: QuoteIndeed, and select a module with 433 or 868 or whichever freq. which is allowed in your area. 2.4 GHz isn't going to work over half a mile.

author: BrianHG
author_rank: Super Contributor
timestamp: May 18, 2024, 02:42:37 pm
content: I've used these transmitters in the past, by passing the onboard IC, for some occasional serial communications. They can achieve 1/2 mile without problems:https://www.aliexpress.us/w/wholesale-433mhz-transmitter-4km.html?spm=a2g0o.productlist.search.0If you cannot code, you can get them with a relay receiver module:TX-RX-combo

author: SanctePieDecime
author_rank: Contributor
timestamp: May 18, 2024, 03:57:19 pm
content: Quote from: tggzzz on May 18, 2024, 02:11:55 pmYou bet. That is why this is in the "Beginners" forum.If there are things that you can tell I would definitely need to know before I continue with this project please point me to some good resources.Quote from: BrianHG on May 18, 2024, 02:42:37 pmQuote from: SiliconWizard on May 18, 2024, 04:49:41 amThank you for these.Quote from: pcprogrammer on May 18, 2024, 06:03:13 amThank you. I was actually wondering if there was a module that I wouldn't need to use a microcontroller for since I wouldn't need one otherwise.Quote from: BennoG on May 18, 2024, 06:19:56 amSo what would your recommendation be to achieve this? Have a unique ID to transmit along with the data?Quote from: radiolistener on May 18, 2024, 09:17:17 amI am not looking to integrate pre-made solutions, but thank you anyway.Quote from: CaptDon on May 18, 2024, 01:56:40 pmWell, the logic gates and sensors are just to determine if there is indeed mail to be picked up.There is a door sensor that would allow me to know when to check for the presence of mail (only check right after the door is closed - with a small delay to allow the flag to go up if it does)There is a sensor for the flag to make sure it isn't just that I put mail in the mailbox to be picked upThere is the actual mail presence sensor (which I am leaning towards IR but I would be interested in a better solution)The logic circuits wouldn't be complicated but they would tell the transmitter whether to transmit a 1 (for if the mail has arrived) or a 0 (for if I just picked up the mail so that the base station returns to its original "awaiting mail" state). I did think about FM briefly. Do you think that would be better for my purposes?Quote from: CaptDon on May 18, 2024, 01:56:40 pmIt is for my own use, but I want to refine it to the point where it could be sold (although I don't really intend to). Again, it is in part to help me learn, and in this case, I am trying to learn how to develop a PCB for my project that doesn't use premade modules (which take up space and look unprofessional to have these just smacked on top of a circuit board that they could have just been integrated into).Quote from: CaptDon on May 18, 2024, 01:56:40 pmThat is partly the idea. I am the sort of person who wants to thorughly understand how something works and as such I have found that building what already exists from scratch helps me learn a lot. But I would not be entirely reinventing the wheel because I would still be using a radio IC and not creating my own from scratch (and I am not sure I would be able to anyway considering that they tend to use non-standard, faster-switching transistors which I assume would be hard to get a hold of even if I wanted to).Quote from: tggzzz on May 18, 2024, 02:11:55 pmI wasn't planning on developing the whole thing from scratch. I was looking to do something more along the lines of integrating the circuit used in the module directly into my PCB design without the extra module circuit board. Ideally, I want to know what pin connects to what on the IC that I use and what it does, as well as how to shift things around on the circuit board to minimize the size required for the circuit board (with consideration taken for parasitics). I do intend to do my initial prototyping with a pre-made module, but after that, I want to collapse everything onto a single circuit board.

author: tggzzz
author_rank: Super Contributor
timestamp: May 18, 2024, 04:06:08 pm
content: Quote from: SanctePieDecime on May 18, 2024, 03:57:19 pmHow manyyearsare you prepared to spend? Seriously.I found Sklar’s Digital Communications: Fundamentals and Applications useful. I suspect you won't.http://www.amazon.co.uk/Digital-Communications-Fundamentals-Bernard-Sklar/dp/1292026065Please don't interleave replies to multiple people making different points. It makes it difficult to understand you, and difficult to strip points out.QuoteYou may not beplanningon that, but that is the consequence of what you are saying.The last part of your response makes this sound like an "XY problem" where you aren't giving us all the information. I don't have time to extract everything from you, one point by one point. (Example: what is thebenefitof re-engineering it onto a single PCB?)

author: SanctePieDecime
author_rank: Contributor
timestamp: May 18, 2024, 04:57:27 pm
content: Quote from: tggzzz on May 18, 2024, 04:06:08 pmI am sorry. I am just trying to answer everyone's questions (in what seems to me to be the most logical order which is mostly chronological).Why wouldn't I find Sklar’s Digital Communications: Fundamentals and Applications useful? Is it because it doesn't actually cover anything that would answer my questions? If it does have the information needed to answer my questions I would love to order it. I am in the USA and was able to change the link to view it for purchase in the USA. I see that the back of the book has a notice that it is not authorized to be sold in the USA so I don't know if I will have trouble ordering it.I am a little disappointed in most of the replies so far. I get that this is something difficult, and time-consuming, and knowledge-intensive. I merely asked for resources on how to integrateexisting radio technologydirectly into a circuit board without using modules but so far most people are just busy pointing out how I am a beginner, and I would be better off using a pre-made module, and how this is something I shouldn't be bothering with. I'll admit that I am quite naive and definitely have a lot to learn, but that is precisely why I am asking for these resources. So far I have not learned anything from this besides that I should probably use a MHz-range transmitter to achieve longer transmission distance.I am well aware there are legal requirements and I don't suspect that I would have much issue with them since all I am trying to do is basically transfer the existing circuit on the module boards directly onto my circuit board while developing an understanding of how the components integrate. As I said,I would be using existing radio ICs.Almost all the responses don't even come close to starting to point me in the right direction. Taking that into consideration and the fact that I have not found anything in my research to start me on the right path I am beginning to wonder if any of you actually know how to do this. This is not meant as an insult, but a legitimate observation that all I can find as answers to my question both in my research and in this forum is: "modules".So I will ask the question again:Would anyone be able to point me to a source explaining how to integrate existing radio ICs directly into my PCB design (without using modules)?This is my question and it doesn't really need more elaboration. Keeping it general means that I can learn how to do this for more than just my specific project.If I am really so naive that I am doomed to fail, then you have nothing to worry about because I won't even be competent enough to get this to work.If you do have any questions that are really necessary to point me in the right direction then ask away.

author: radiolistener
author_rank: Super Contributor
timestamp: May 18, 2024, 05:16:38 pm
content: Quote from: SanctePieDecime on May 18, 2024, 03:57:19 pmThis is in vain. Such solution will be much more easy, cheaper and more reliable.From your question it is clear that you're don't have enough knowledge to even understand suggestiongs, so it's hard to explain things for you. I'm sure if you're want to design RF transmitter as a newbie, you will fail, because it requires some knowledge and experience in this area. And obtaining such knowledge needs pretty much time for learning. So, it's much more effective and cheaper solution for you to use already designed modules.For example, I can design and tune such transmitter, I have experience and many measurement equipment required to tune and test it, but if I needed such a solution, I would use ready-made modules, just because it's easier and cheaper.Quote from: SanctePieDecime on May 18, 2024, 04:57:27 pmI'm afraid there is no simple "point to" way. If you want to start, the most easy way is to learn some ready to use modules. When you will be familiar on how to use it, then it will be more easy to learn how they work and then how to implement the same circuit. Unfortunately there is no simple way to design some complex thing which requires specific knowledge in the area with no learning basic things and with no experience.

author: SanctePieDecime
author_rank: Contributor
timestamp: May 18, 2024, 05:27:08 pm
content: Quote from: radiolistener on May 18, 2024, 05:16:38 pmLike I said. I am not designing anything new I am basically just transferring an already existing design onto my PCB design.Here is the best analogy I can use. Using an Arduino is good for prototyping, but eventualy you want to move away from it (and use the barebones ATMEGA328 without any of the circuitry that you don't need) in a final product. So too with the radio module but in a slightly different way. Just as using the ATMEGA328 directly on your circuit is more space-efficient and cost-efficient than using the whole Arduino, so too with the radio communications system.

author: globoy
author_rank: Frequent Contributor
timestamp: May 18, 2024, 05:41:51 pm
content: Quote from: SanctePieDecime on May 18, 2024, 04:57:27 pmProbably there is no one single source to explain this since it touches a number of topics.You can probably understand what circuitry is needed to support any particular radio IC by looking at its user manual and/or by looking at the schematics for modules that use it.The circuitry needed to operate the radio IC will vary depending on what radio IC you choose. Most are designed to be controlled by an external (or internal) micro-controller via an industry standard interface such as I2C or SPI. Your particular application will determine other aspects of the other circuitry such as interface to sensors and power supply/power management. The devil is in the details here and you haven't shared enough specific information to suggest specific solutions.You will probably need to tune the RF Output circuitry of your design. This is the aspect that is causing most people to suggest using a pre-built module. The tuning itself depends on the circuit (matching circuitry, frequency, antenna type, etc) and is a process that requires some expertise and specialized measurement tools. Do a search for "tuning pcb antenna matching circuits" or something like that to get an idea. Tuning can mean the difference between a transmitter that can transmit 10 feet or one that can transmit 1000 feet.Maybe I missed it but is this a "one-off" (just for you) or you want to design something that you will manufacture, market and sell? If it's going to be for sale then you will need to contend with regulatory approvals (e.g. FCC, CE) as well - and probably you should put in place a whole validation/verification effort to make sure your device works as intended in all the various situations it will find itself. If it's a one-off then you can get by without sweating any of those issues.Engineering design is a process that involves setting requirements/goals and then looking for solutions to implement those and dealing with all the various compromises/decision points that come up, as well as considerations for the regulatory and manufacturing requirements of hardware products. It's great (IMHO) that you're interested in pursuing this for your own edification but often someone who is beginning doesn't really understand what they are asking for and either doesn't know to include certain details in their questions that are necessary to get good answers or significantly underestimates the problem they are trying to solve. Add that to the semi-anonymous nature of a medium such as this one and you get a lot of responses such as the ones you've just seen.If this were my project - lol, and I have thought about automating my mailbox but am just too lazy - I'd probably settle on a LoRa radio module and some simple micro-controller capable of very low power operation. Or if I really wanted to do the radio part too, I'd include the LoRa IC on my board (understanding I'd just bitten off more work and expense).

author: radiolistener
author_rank: Super Contributor
timestamp: May 18, 2024, 05:46:48 pm
content: Quote from: SanctePieDecime on May 18, 2024, 05:27:08 pmEven in this case using ready to use module will be the most efficient and cheaper solution. Designing RF transmitter is not easy like designing hobby digital arduino circuit. It requires to understand many things like transmission lines, impedance matching, etc. As other said here, this isdefinitelynot a task for beginner. If you're want to start such design with no knowledge and experience, I bet you will fail.

author: armandine2
author_rank: Frequent Contributor
timestamp: May 18, 2024, 05:55:32 pm
content: you might be able to avoid the thousand page book, or some of it at least

author: tggzzz
author_rank: Super Contributor
timestamp: May 18, 2024, 06:17:20 pm
content: Quote from: SanctePieDecime on May 18, 2024, 04:57:27 pmSigh.Start with knowing the FCC regulations that apply, and understanding them. Move onto the physics of PCBs and antennas and propagation. Proceed to being able to configure and test the implementation. End up with getting regulatory approval for your device.Yes, some of could do it. We also know how much time and effort it would take.That'swhy we wouldn't bother.But, hey, go knock yourself out!

author: radiolistener
author_rank: Super Contributor
timestamp: May 18, 2024, 06:18:15 pm
content: Quote from: SanctePieDecime on May 18, 2024, 04:57:27 pmIn short: first you're needs to select working frequency, then you're needs to select modulation which you're want to use. Then you're needs to decide where you will do modulation - in digital domain as DSP or in analog domain as hardware analog modulator. In that way you can implement IF stage of transmitter. Then you're needs oscillator and mixer and do frequency shift from IF to working frequency. Then add RF amplifier, filters and matching circuit to match it with antenna. Then you will need to tune all things and debug it.And before use it with antenna you will needs to measure it's spectrum and check if it comply with government regulations. Most of all it will not, so you will need to fix it by adding proper filter, change some components or properly tuning it.If you knew how much knowledge, time and measuring equipment this would require, then I am sure you would lose interest in independent development. And since you're newbie and don't have knowledge in this area, this is why no one even don't start to suggest you on how to do it.

author: tggzzz
author_rank: Super Contributor
timestamp: May 18, 2024, 06:22:27 pm
content: Quote from: radiolistener on May 18, 2024, 06:18:15 pmI suppose we could just point the OP to investigate the cost of abasicRF test setup that is sufficient to measure the harmonic and intermodulation products. Without that, regulatory approval will be a slow iterative (and expensive!) process

author: tggzzz
author_rank: Super Contributor
timestamp: May 18, 2024, 06:29:55 pm
content: OP...Why don't you start with the most basic design parameters: the link budget.That means understanding the tx power, the tx antenna properties, the path parameters (loss, fading, multipath, Fresnel zone), the modulation scheme, the rx antenna, the rx noise and susceptability, the allowable error rate, the channel coding.Or, if you use modules, you only have to understand the tx/rx antennas and the path parameters. Don't fall into the beginner trap of thinking you can increase the margin by putting a high-gain antenna on the transmitter. For an X dB antenna gain you are required to reduce the tx by X dB. That doesn't apply to the rx antenna.

author: pcprogrammer
author_rank: Super Contributor
timestamp: May 18, 2024, 06:56:29 pm
content: One simple solution that might work but won't reduce on space that much is to get a set of modules that suit your purpose, take a close look at the PCB layout and copy that exactly onto your own PCB design, de-solder the components from the module and reuse them on your own PCB. That way there is a higher certainty that it works, but still no guarantee. Not very handy for serial production, but as others stated, a new product that uses radio waves needs certification before it can be legally sold.The field of electronics is very wide, ranging from analog to digital, high/low voltage, high/low current, high/low frequency, making it very difficult to shine in every aspect of it. I myself are more a programmer, but have learned the basics of electronics and forgot a lot of it over the many years. I'm getting back into the game, but know my limitations. RF is a very difficult field that I rather leave to the experts, but still like to do remote control stuff. For that I just buy ready made modules known to be working and connect them to microcontrollers. Even when designing my own PCB's, I rather put a connector on it to connect the module to then put the components directly on the PCB and have to redo it several times because I missed some specific aspect about RF.So if you really want to learn about RF, I applaud you, but if it is just about this simple project, I would say stick to the modules and call it the day. Otherwise you should start at the beginning and get some books about basic RF design and what it all entails.

author: xvr
author_rank: Frequent Contributor
timestamp: May 18, 2024, 08:05:21 pm
content: QuoteExisting design here is not just IC, but the whole module. IC just a small part of internals of it. Antena, PCB geometry and passives are also a part of "existing design". Even if you duplicate module on your PCB it would beanotherdevice and you will have to obtain FCC sertification for it as for absolutely new design.Even incorporating ready made module in your design as-is still could require FCC sertification of final product (thought may be not so strict as designing it from blank paper)

author: radiolistener
author_rank: Super Contributor
timestamp: May 18, 2024, 08:54:18 pm
content: Stupid copy of PCB layout from module also may not work here, because it don't take into account wave properties of PCB material and mask and RF circuit usually has tunable parts of circuit which has unique components for every PCB which is tuned/selected with proper measurement equipment. So, if you're just copy PCB layout geometry with keep the same wire size and geometry (which is important for RF circuits), this is still may not be enough to get properly working RF circuit.This is why using ready made RF module is more easy and cheap way, it don't require deep knowledge in RF design and many measurement equipment to tune it. In that way it can be used by newbie. While proper design of RF circuit (especially which working at VHF/UHF band) will be real headache even for experienced guy, and almost impossible for newbie.

author: SanctePieDecime
author_rank: Contributor
timestamp: May 20, 2024, 01:31:59 am
content: Thank you all sooo much for all of your contributions. I think that I now have a bit of a starting point to go on. I will definitely come here if I get stuck and can't find any solutions to my problems.I definitely understand that PCBs will have variations depending on parameters and even manufacturers, and as such (taking parasitics into consideration) I can't just do a direct copy of a module design (which is the reason I asked the question).I understand that the "mission I am embarking upon" is not an easy one even for those with experience (which could even be said to be an understatement), but I would not have even considered this if I did not believe it was possible. I have my mind set on "embarking on this journey" and even if I am not successful I do not count that as a loss because it will have been a learning experience. I will try to document as much of this as possible and will probably post my results here if I am successful (and if I am not, the documentation can serve as a way of showing the work I have done and people can point out to me where I went wrong).Anyway, thank you again for all of your help and I apologize for any headache I may have caused any of you.

author: selcuk
author_rank: Frequent Contributor
timestamp: May 20, 2024, 07:34:50 am
content: You can read datasheets, hardware design manuals and application notes of the MCUs for bare chip designs. They have specific information for each MCU. Your project is suitable to develop with Lora and similar but for learning purposes it may not be the best. Low power and short range communication like BLE is better for first RF designs. There are highly integrated MCUs like nRF52 series, so that MCU includes all the RF blocks except the antenna. You don't need to do an RF amplifier with transistors in the beginning. This is nrf52810 datasheet for example:https://infocenter.nordicsemi.com/pdf/nRF52810_PS_v1.3.pdfCheck section "7.3.3 Schematic QCAA QFN32 with internal LDO regulator setup" on page 398. And section "7.3.8 PCB guidelines" on page 404. It is not that complicated. You will need to have an idea about RF theory. You may use a chip antenna. Its application note will give the information about the layout. Or you may use a PCB antenna. You can copy an existing antenna design into your board. Check the attached application notes. There are much more on the internet.You can design a new antenna for your board. But it may take longer time and needs more knowledge about RF. You can check this link to have an idea. It is not suitable for your long range communication requirement. Consider it as an example for bare MCU and PCB antenna design.https://www.eevblog.com/forum/oshw/esp32-ethernet-wi-fi-serial-gateway/

author: tggzzz
author_rank: Super Contributor
timestamp: May 20, 2024, 08:26:42 am
content: Quote from: SanctePieDecime on May 20, 2024, 01:31:59 amDon't worry about any headache you might have causedus; we're used to itDo worry about any headache you might causepeopleandbusinessesnear one of your transmitters. Although you are well-intentioned, you don't know enough to adequately test your devices.

author: ftg
author_rank: Frequent Contributor
timestamp: May 20, 2024, 08:57:25 am
content: Quote from: SanctePieDecime on May 18, 2024, 04:57:27 pmThe source is the manufacturers documentation for the chip you have chosen for your application.Some common examples are:CC1101 from Texas Instruments:https://www.ti.com/product/CC1101?keyMatch=CC1101&tisearch=search-everything&usecase=GPN-ALT#tech-docsSi4432 from Silicon Laboratories:https://www.silabs.com/wireless/proprietary/ezradiopro-sub-ghz-ics/device.si4432?tab=techdocsSX1262 from Semtech:https://www.semtech.com/products/wireless-rf/lora-connect/sx1262#documentationFor all of those the manufacturer has application notes and documentation on how to realize the layout.But some additional equipment is required for verifying the design, especially the spurious emissions.Also, when one prices out the solution, it becomes apparent that in small volumes the modules might be actually cheaper than buying the parts from digikey or mouser.

author: tggzzz
author_rank: Super Contributor
timestamp: May 20, 2024, 09:00:36 am
content: Quote from: ftg on May 20, 2024, 08:57:25 amEspecially if you add the cost of your time and the cost of the necessary test equipment