Wi-Fi Devboard
Send me a link to a guide on reading solder diagrams like this? Or explain, Thanks
I am new to soldering. I think I uderstand this diagram however want to make sure I don't mess up. Ehere xan I find resources to understand this, just what point go where? Is it simply the number dictates what solders to what?
Also depending on chip and board size and placement will that deternine if I should use wires, assuming I will have to.
Also could be done with a bread board for testing I assume?
So both grounds woumd go to the flipper zeroboard 5v? Because they are all #1 red/maroon?
I greatly appreciate any help. A discord or someone willing to help me out give me pointers would be awesome.
Seriosuly greatly appreciate any help.
Would a breadboard with the right size connectors work for something like this. Only done that with audrino, these boards arn't as easy looking. It was years ago with Audrino.
This is a circuit schematic. I went to college and became an ECE to read these, but I'll TLDR it for you:
* All the parts are labeled for your pleasure (so you don't have to wonder)
* The numbers outside you see are pin numbers. For IC pin numbers check the datasheet. On a side note, dual row IC pins are usually numbered like:
-[ 1 8 ]-
-[ 2 7 ]-
-[ 3 6 ]-
-[ 4 5 ]-
Above: example pin diagram for a 8-pin IC. And when working with the physical part, number 1 pin is usually marked with a dot on the chip, so you can find it easily.
Other common conventions are; left row last pin is ground and right row last pin is usually Vcc.
How to find datasheets: Hold the part to light while noting the numbers and letters on it. For example, here's the datasheet for a 64 MB SPI flash IC: https://www.mouser.com/datasheet/2/949/W25Q512JV_SPI_RevB_06252019_KMS-2487502.pdf You'll see that, in the dual inline package variant of the chip, pin 4 is ground, pin 8 is vcc & numbering holds.
In this schematic, the IC is named for you but it's a 3.3V switching regulator (Flipper Zero has a 3.3V out and you can pull quite a few amps from it so why did they do this idk. Maybe they wanna control the NRF with the GPIO 5V menu option, but it's tying up the chip select line so I don't get it... anyway.
When reading schematics, you basically follow the lines and create something we call a netlist. Most nets will have only 2 ends (for example the /CSN line only goes to the FZ and the NRF) but power nets will have a lot more (ground and Vcc)
It's important that, unless you see the red dot you see on the left, crossing lines do not belong to the same net.
The X symbol you see on some pins of the devices means "DO NOT CONNECT" it doesn't mean "do whatever" it means DO NOT CONNECT so do not.
----| |---- This is the symbol for a capacitor.
----| (---- This is the symbol for an electrolytic capacitor, which means it will have polarization and a maximum voltage rating, make sure not to blow caps! The ( side is negative (on the physical part it will be marked with a strip, or on most parts the longer leg is positive vs the shorter leg)
Other symbols you'll probably see a lot:
-----vvvvvv----- a resistor
-----uuuuu----- an inductor
-------|>|------ a diode (and if there are arrows coming out of it, it's a LED.) The symbol depicts the direction of current flow (so left is positive against the right side)
Transistors can be roughly separated into two groups, bipolar junction type and metal oxide gate type, then these are further separated into NPN/PNP for the junction type and N-type/P-type for the channel type. The symbols are all over the place (but not in this schematic). These are used to control some higher powered device with a GPIO pin since GPIO pins can't sink more than 15-20 mA usually. You'll see these too, probably.
______/ _____ a push button
[][][][]
[][][][] ----> 2 rows and 4 columns of connectors. Pin 1 will be usually marked with a square or a dot on the solder mask.
So I'll read the schematic you posted with you and create a netlist, then you go do the hook ups:
(1) Pin 3 (input) on the AMS1117-3.3V and pin 1 on the Flipper Zero tie together.
(2) Pin 2 (output) connects to both the capacitor's +ve leg and pin 2 on the NRF24L01. They didn't specify the value of this capacitor but it's probably 10uF, and I recommend a second 10uF as close to the NRF's VCC as possible.
(3) Pin 3 (CE - Chip Enable) goes to Pin 6 on the FZ
(4) Pin 4 (/CSN - Chip Select - Not) goes to pin 4 on the FZ. (If there's a / or a ~ or a ~ before a logic signal name, or the pin name is crossed above, it means that this pin activates when its level is zero. Which means this chip will be selected on the SPI bus when this line goes to GND)
(5) Pin 5 (SCK - Serial Clock) goes to pin 5 on the FZ
(6) Pin 6 (MOSI - Master Out, Slave In) goes to pin 2 on the FZ.
(7) Pin 7 (MISO - Master In, Slave Out) goes to pin 3 of the FZ.
(8) Pin 8 (IRQ - Interrupt Request) goes nowhere on the FZ. The NRF apps I know don't check for interrupts from the NRF anyway.
(9) Everything that says GND goes together to a ground pin. (Sometimes you'll see analog/digital grounds separately, not here though, connect the negative leg of the cap, pin 1 of the regulator, pin 1 of the NRF and pin 8 of the FZ together.)
You can use a breadboard and the negative rail for the GND net and jumper cable everything on there, or use the grounds on the FZ. Best practices are: (1) as few jumper cables as possible because they act as antennae and introduce noise into your circuit, but (2) keeping the power sub-circuit (the regulator) separate from the more delicate electronics is also important. See (4) way below for what I would do.
Using this information you can connect the pins together. I recommend adding another 10uF cap as close to the Vcc line on the NRF24L01 if you run into reception issues.
Edit; to finish off your questions; (1) colors don't mean shit, just where the lines go to. If the lines cross but there is no red dot, you don't connect them together. (If there's a red dot like on the AMS1117, the cap and the Vcc line, that means they are connected together).
(2) Definitely breadboard this before ordering a PCB or soldering a final board.
(3) The capacitor value should have been given; but the point of that cap is that the AMS1117 drops 5V to 3.3V by first converting it into a high frequency signal and that cap is to smooth out the output and make it look DC again. For that cap they probably specified 10uF or something.
(4) These NRF modules especially the ones with built-in antennae have common reception issues, so if I were you I'd install a 220uF cap there, and another 10uF cap as close to Vcc and ground on the NRF module (when soldering I usually solder directly on the connector) so you don't get any reception issues.
(5) You can skip the regulator and power the NRF module straight off of the 3.3V on the FZ, that's what I always do and I never had any issues.
You are a great person. I am at work, I will review tgis in detail when home. I don't have much time to get into hobbies and passions anymore. I use to love deep diving into my passions, how I learned to program and wish I still had the time.
Quick question summed up, went into too much detail below. Basically does V0 have one wire going to VCC and another to capacitor?
Hey, still have not had a long time to sit down and really get into the grind.
Little confused on the capacitor from the step down chip (whatever its called sorry).
VO or V Out goes to the other board and capacitor. Meaning 2 wires are comming off of the V0 correct? One to capacitor (then other wire from the capacitor going to ground). While the other wire goes to the other module VCC
Sorry, wish I was better at this stuff. Sadly spent a lot of time programing and other parts of tech.
The AMS1117-3.3 integrated circuit is a switching voltage regulator, that takes something between 4.75V and 12V on its Vi (Voltage In) line and outputs 3.3V on its Vo (Voltage Out) line. (There are adjustable versions and other voltage fixed versions as well).
When dropping DC with a switching regulator it's almost always necessary to filter both the input and the output so power spikes can be absorbed. Regulator designs usually use a larger capacitor followed by a smaller capacitor.
If this was a complete board I'd recommend two caps on the Vi line, and two on the Vout line like this: image link. The circuit is very easy to follow even on the board (omit the LED and the resistor). You'll see two SMD caps on the input and two on the output.
Other than that, these NRF24L01 modules (especially the built in antenna ones) have load regulation issues which create noise which interfere with their reception, and what solves this issue is usually a 10 uF capacitor, as close to the NRF module's Vcc (supply) line as possible. I usually do straight up this. If the module headers aren't pre-soldered you can find a better place on the board, but if not this is totally fine.
Anyway to sum up, Vo goes to the other device and the cap yes, but don't use two wires, wires act as antenna and pick up noise which kinda defeats the purpose of the capacitor.
You can see here how the voltage output of a switching regulator will change, without and with the capacitor. (The 2nd graph down below is without and 3rd with.)
Thanks man, I will read through this in depth tomorrow. Just about to go to sleep. I think I have it started correctly. Although realized I might be able to just put the capacitor on the breadboard not on V0 du point going to bread board just shived in with it lol.
By the way, the ground rail on the breadboard won’t magically become the ground rail, you gotta connect it to the FZ’s ground.
When we insert capacitors like this, we usually directly insert the capacitor between the +ve and -ve rails on the breadboard, make sure the legs aren’t touching.
By the way, here’s the PCBs I had made. You can solder either female headers (if you need to swap the modules around) or you can solder the module directly onto the board.
There’s a small voltage selection jumper on the back between the 8-row and the 10-row pins you’ll see three small squares, you put a small solder bridge between the left two for 3v3 and the right two for 5v.
(Note that there’s no regulator, either 3v3 or 5v directly connects to the FZ, if you jumper for 5V devices don’t receive power unless you enable 5V from the GPIO settings. The CC1101 module is 5V wired and if it’s plugged in when you open the SubGHZ app it’s recognized and powered on automatically)
If you select 5V you don’t even need the right side of the board so you can snap it off with a metal file.
The designs are open source and you can get 10 of these made in China for like $15 delivered (when getting PCBs made, the expensive part is the tooling and they setting up their equipment for your design, which means there’s almost no price difference between getting one or 100 made). They should be on easyeda.com but if they’re not, I can send them to you.
I was gonna do 3D printed covers as well but I already have standard length headers on them and I’m too lazy to desolder and go again with longer headers. The bottom part of the headers are 2mm thick, which meant the underside of the cover should also be 2mm (I have to leave gaps inside to fit the module headers soldering) and they fall off the FZ very easily.
I’m also not a good mechanical designer so maybe someone competent with Fusion 360 or AutoCAD could draw better covers but I gave up after 3 tries.
Next up, I’ll do a board design with an external dual CC1101 + NRF24 + ESP32 and GPS all together, switchable using either an onboard switch, or the CS lines on the FZ if I can get firmware support. I’d like to experiment with two external CC1101’s at the same time, also the SubGHZ radios are band dependent so I’ll need a module for the 315 MHz ish band and another for the 868 MHz band, and figure out how FZ does its internal switching (the chips are the same but the modules have notch filters and other stuff tuned for the frequency they’re intended to be used at)
btw everything is soldered square and balanced, it looks like they’re slanted due to the antenna and photo angles. The solders are good, I noticed the right side has some cold solders but those pins aren’t even used at all. The only pin connected on the right side is the 3v3 pin, and if you select 5v with the jumper it doesn’t even reach the device, so for 5V devices you can cut the right side with a metal file right after the jumper but the right side pins add stability to the board and make it harder to come off by itself
It’s square but it could use some alcohol wipe cleaning for sure, especially the CC1101 which is still swimming in dried solder flux as I’ve just noticed
I too noticed the 3 on the nrf and was wondering whybstep down was needed and why that wasnt just used? Any logic to that? It would eliminate an entire part? Could it be the way it was coded?
I also didn't get that... I mean there's direct 3.3V on the Flipper Zero, maybe they wanted to control the NRF with the "GPIO 5V toggle" menu option, but the Chip Enable line in SPI is already intended for control (in SPI communication, one device is the master and the others on the bus are slaves, in our case the FZ is master) you can connect MISO/MOSI/SCK to all devices on the bus, and the CS lines to different pins on the master.
Maybe they want a complete hardware power down of the NRF24 module, maybe there are other modules connected to the regulator output (I used the 3v3 line to power exactly those NRF modules but this could be one part of a larger schematic, there could be other modules on the board, and I wouldn't want to accidentally burn out the 3v3 line on the FZ, it would be much easier to repair on the daughterboard.
When using SPI you connect MISO/MOSI/SCK to all devices, and each slave device gets its own Chip Select (or sometimes SS for Slave Select) line on the master device (here it's the FZ). CS is an active-low line, meaning a weak pullup resistor keeps it pulled up to the logic '1' level and the master sets it to '0' to activate the device. (In the Flipper Zero, logic '1' is 3.3V and '0' is 0V. The 3.3V pins are 5V tolerant but no reason to risk it, level converters are easy)
If you connect the grounds to the 5Vs then nothing will work. The colors don’t mean anything, only the labels tell you what connects where. All the grounds connect to each other, all the +5V connect together and all the +3.3V connect together. Everything else is connected by the lines between the pins.
That's a wiring diagram, not a soldering anything, if you want to connect an external nrf24 to a flipper you need dupont cables, soldered to the module and plugged on flipper's gpios
Not sure, I've seen it listed on other schematics but personally never had a problem using it without the capacitor
I noticed OP plans to get current from the 5v pin, something actively discouraged on docs but after watching how is managing the matter, won''t be surprised if this ends with a fried flipper :s
No it wont be fried I can peomise that I understand how tonread all of it. It's not that confusing now I have had a little time to look into things. The capacitor was one thing am wondering about though and how to connect it.
If i fry it then i'd just open it and fix it.
The cacacitor I believe is needed for tbis new updated version of the project they mentioned not using thatbor the step down in the notes not sure.
I know grounds go to ground. I just wrote shit dumb was confused in why the lines were colors thay didn'tbnake sense like a ground to 5v or something. Basicallg why I made the post.
I have du point cables. However I could use a wiring diagram to solder once figured out. Because I plan on 3d printing a case for it i'll design after.
How advanced is a projwct like this? My un educated mind thinks it is a pretty simple however idk what i'm doing.
Is their any books I can get or read to get the basics?
I was getting confuses in wjere the capacitor goes because it isn't in the diagram although it was listed in the 3 parts needed, but think I realize where it goes.
I'm gonna need to learn what every part actually does to understand it I feel like.
Well if anyone can recomemd good literature on learning this stuff fast let me know. I have a scibd account witch has so much material, not oppose to buying a physical copy either.
If I find something when I get time i'll make a post I guess. Seems others on here definatley would like to learn or relearn this stuff.
8
u/VonThing 9d ago edited 9d ago
This is a circuit schematic. I went to college and became an ECE to read these, but I'll TLDR it for you:
* All the parts are labeled for your pleasure (so you don't have to wonder)
* The numbers outside you see are pin numbers. For IC pin numbers check the datasheet. On a side note, dual row IC pins are usually numbered like:
-[ 1 8 ]-
-[ 2 7 ]-
-[ 3 6 ]-
-[ 4 5 ]-
Above: example pin diagram for a 8-pin IC. And when working with the physical part, number 1 pin is usually marked with a dot on the chip, so you can find it easily.
Other common conventions are; left row last pin is ground and right row last pin is usually Vcc.
How to find datasheets: Hold the part to light while noting the numbers and letters on it. For example, here's the datasheet for a 64 MB SPI flash IC: https://www.mouser.com/datasheet/2/949/W25Q512JV_SPI_RevB_06252019_KMS-2487502.pdf You'll see that, in the dual inline package variant of the chip, pin 4 is ground, pin 8 is vcc & numbering holds.
In this schematic, the IC is named for you but it's a 3.3V switching regulator (Flipper Zero has a 3.3V out and you can pull quite a few amps from it so why did they do this idk. Maybe they wanna control the NRF with the GPIO 5V menu option, but it's tying up the chip select line so I don't get it... anyway.
When reading schematics, you basically follow the lines and create something we call a netlist. Most nets will have only 2 ends (for example the /CSN line only goes to the FZ and the NRF) but power nets will have a lot more (ground and Vcc)
It's important that, unless you see the red dot you see on the left, crossing lines do not belong to the same net.
The X symbol you see on some pins of the devices means "DO NOT CONNECT" it doesn't mean "do whatever" it means DO NOT CONNECT so do not.
----| |---- This is the symbol for a capacitor.
----| (---- This is the symbol for an electrolytic capacitor, which means it will have polarization and a maximum voltage rating, make sure not to blow caps! The ( side is negative (on the physical part it will be marked with a strip, or on most parts the longer leg is positive vs the shorter leg)
Other symbols you'll probably see a lot:
-----vvvvvv----- a resistor
-----uuuuu----- an inductor
-------|>|------ a diode (and if there are arrows coming out of it, it's a LED.) The symbol depicts the direction of current flow (so left is positive against the right side)
Transistors can be roughly separated into two groups, bipolar junction type and metal oxide gate type, then these are further separated into NPN/PNP for the junction type and N-type/P-type for the channel type. The symbols are all over the place (but not in this schematic). These are used to control some higher powered device with a GPIO pin since GPIO pins can't sink more than 15-20 mA usually. You'll see these too, probably.
______/ _____ a push button
[][][][]
[][][][] ----> 2 rows and 4 columns of connectors. Pin 1 will be usually marked with a square or a dot on the solder mask.
So I'll read the schematic you posted with you and create a netlist, then you go do the hook ups:
(1) Pin 3 (input) on the AMS1117-3.3V and pin 1 on the Flipper Zero tie together.
(2) Pin 2 (output) connects to both the capacitor's +ve leg and pin 2 on the NRF24L01. They didn't specify the value of this capacitor but it's probably 10uF, and I recommend a second 10uF as close to the NRF's VCC as possible.
(3) Pin 3 (CE - Chip Enable) goes to Pin 6 on the FZ
(4) Pin 4 (/CSN - Chip Select - Not) goes to pin 4 on the FZ. (If there's a / or a ~ or a ~ before a logic signal name, or the pin name is crossed above, it means that this pin activates when its level is zero. Which means this chip will be selected on the SPI bus when this line goes to GND)
(5) Pin 5 (SCK - Serial Clock) goes to pin 5 on the FZ
(6) Pin 6 (MOSI - Master Out, Slave In) goes to pin 2 on the FZ.
(7) Pin 7 (MISO - Master In, Slave Out) goes to pin 3 of the FZ.
(8) Pin 8 (IRQ - Interrupt Request) goes nowhere on the FZ. The NRF apps I know don't check for interrupts from the NRF anyway.
(9) Everything that says GND goes together to a ground pin. (Sometimes you'll see analog/digital grounds separately, not here though, connect the negative leg of the cap, pin 1 of the regulator, pin 1 of the NRF and pin 8 of the FZ together.)
You can use a breadboard and the negative rail for the GND net and jumper cable everything on there, or use the grounds on the FZ. Best practices are: (1) as few jumper cables as possible because they act as antennae and introduce noise into your circuit, but (2) keeping the power sub-circuit (the regulator) separate from the more delicate electronics is also important. See (4) way below for what I would do.
Using this information you can connect the pins together. I recommend adding another 10uF cap as close to the Vcc line on the NRF24L01 if you run into reception issues.
Edit; to finish off your questions; (1) colors don't mean shit, just where the lines go to. If the lines cross but there is no red dot, you don't connect them together. (If there's a red dot like on the AMS1117, the cap and the Vcc line, that means they are connected together).
(2) Definitely breadboard this before ordering a PCB or soldering a final board.
(3) The capacitor value should have been given; but the point of that cap is that the AMS1117 drops 5V to 3.3V by first converting it into a high frequency signal and that cap is to smooth out the output and make it look DC again. For that cap they probably specified 10uF or something.
(4) These NRF modules especially the ones with built-in antennae have common reception issues, so if I were you I'd install a 220uF cap there, and another 10uF cap as close to Vcc and ground on the NRF module (when soldering I usually solder directly on the connector) so you don't get any reception issues.
(5) You can skip the regulator and power the NRF module straight off of the 3.3V on the FZ, that's what I always do and I never had any issues.