I'm excited to share my current project with you all. I've been working on an Arduino project and I've reached the stage where I need to design a PCB for it. I already have my circuit ready, which consists of a DFR0478, an ADXL 345 sensor, SX1278 Ra-02 433 MHz, and a DS3231. However, I've encountered a little hurdle: the NPN transistors that appear in the fireBettle I'm using.
I've been searching for information about the values of these transistors, but I haven't had any luck. Has anyone here designed a fireBettle ESP32 from scratch and could offer guidance on the values of the NPN transistors? I'm designing in EASYEDA.
On another note, I want to ensure that the power consumption of my project remains low. Currently, it consumes only 0.2 mA, and I'd like to maintain that same level of consumption when transferring it to the PCB. Does anyone have tips on how to achieve this during the PCB design process?
This is the circuit I found for the DFR0478. I have doubts about the value of the NPNs and also about what this component is. I've encircled it in a red box.
I was looking at the board and the transistors are marked 'j3y'. Look for that reference in easyEDA and find this one, I don't know if it changes anything compared to others.
I moved your topic to an appropriate forum category @alexander_idid.
In the future, please take some time to pick the forum category that best suits the subject of your topic. There is an "About the _____ category" topic at the top of each category that explains its purpose.
I've almost finished the circuit diagram, I still need to put in the diode and the crystal, I haven't put them in because I don't know which reference is appropriate considering that I have to keep the consumption low. Could someone give me a feedBack, and another question, I don't quite understand where the VB voltage comes from, could someone explain to me?
Did you know that you can search a PDF which contains a vector image for any text, That is what I did here. Of course it will not work if the PDF contains a bit image.
Also as it stands what you have posted has the resolution too low. That is you need to post a bigger image for it to be useful.
I have a question, for example, I found a reference of the ESP32 that I use in EasyEda given by the contributors, but how can I know if the circuit is good? That is, see how the internal components?
This is the block that appears, which apparently represents DFR0478, but how can I see the content to see if the circuit is correct or to base it on that
It looks odd. Normally pin 1 is at the top left hand corner over a dot or indentation on the top of the package. Then the pins are labeled anti clockwise round the package.
I don't understand you on this. It is a schematic representation of the ESP1 DFR0478. You are not supposed to "see inside it" to know it is good or otherwise. It is just the module itself.
I suppose you could try and find the data sheet
Start looking here
Ok, thank you @Grumpy_Mike , but I have a question, I'm new to the PCB, if I use that DFR0478 schematic, would it save me the trouble of doing it from scratch, like I'm doing right now?
That's a good question. You could simply treat the DFR0478 as a module and place it on your custom PCB through e.g. pin headers. It'll plug right into two parallel sets of female headers with appropriate spacing.
Okay, but when I print the pcb, will the DFR0478 already come on the board? That is, its components are already on the pcb or do I have to buy it and insert it through pins?
A PCB manufacturing service like JLCPCB will only mount components (1) if you ask them to and (2) if the components are in their catalog. I assume that boards like the DRF0478 will not by default be in their inventory, but you'll have to check with the manufacturer of your choice.
I assume that means you are new to PCB design.
That is one hell of a project to start on first of all. I don't think you stand much chance of doing it yourself.
What PCB layout program do you plan to use?
Do you know about through holes and solder masks?
What changes do you want to make from the existing part you can buy?
Or are you out to rip off DF-Robot design and sell it yourself? If so it will cost you one hell of a lot more money because you do not have the buying power to be able to buy parts in bulk.
Also, assuming you are from the USA, then you will need to test the finished product in an FCC approved test house to see if your version is below the required EM emissions and EM susceptibility values. These test houses cost in excess of $1000 a day.
So my biggest tip for Circuit design on a PCB is to not bother.
I think you misunderstand. The way I read this, @alexander_idid has a system that consists of a DFR0478 and a couple of other modules. He now apparently wants to integrate this onto a PCB instead of connecting everything with flying wires or a breadboard.
It seems he went off into the deep end and started unpacking the DFR0478 black box and re-creating it on his own PCB, along with the other stuff his project consists of. So it's not a carbon-copy of the DFR board. In principle, there's not all that much wrong with doing it this way; I'm sure many of us have done similar things (I sure have). However, the question is how useful it is - I agree with you on that.
Especially for a first-time project, there's not much wrong with keeping the DFR board the black box that it is and just dropping it onto the custom 'backplane' PCB as-is, along with the other modules. It's a fine way to ease into PCB layout. We see many people do it this way on this forum on a weekly basis. Sure he's going to make mistakes; it's part of the learning process.
OK, but reading it again it was still not clear to me.
What I would do in this case is to design your PCB so that it had on it a a set of holes where you could just wire in an actual FireBeetle, and then add the rest of the stuff you want to include, including the tracks that connect the FireBeetle to your other parts. That is what I would do if faced with the same problem.
But then I have had experience with several different PCB layout programs, both commercial, open source, and even one I wrote in the Forth language for my Mac back in the late 1980s.
I agree; and I'd recommend to solder female pin headers into the set of holes for the FireBeetle so it can easily be taken out of the circuit as well, allowing itself to be reused in a future project and/or for troubleshooting purposes.
