ESP32 + PCB Antenna Hardware Design Tutorial - Phil's Lab #90

in this video I'll show you how to create your very own custom esp32 based hardware and incorporate a PCB antenna in your own designs we'll go through schematics PCB design and firmware in the form of a Wi-Fi scanner example using the Arduino IDE and esp32 plugins to test the functionality at the end of this video make sure to subscribe to the channel to be notified about upcoming esp32 firmware development videos for these custom pcbs without further Ado let's get started thank you very much for altering for sponsoring this video I use Autumn designer to design these esp32 C3 based dongles and I'll be going through the design in this video if you'd like to follow along or give Alton designer a try for yourself make sure to check out the link in the description below or go to alton.com forward slash YT forward slash Phil's lab to get yourself an Autumn designer free trial thank you also very much to PCB way for sponsoring this video These esp32 pcbs with PCB antennas were manufactured and assembled by PCB way in China I'll leave a link to their site in the description below make sure also to follow them on Instagram where you can see some of my designs sometimes featured and give you hints what will be upcoming in future videos of course you can also follow my Instagram and I'll leave a link to that in the description below where you can see sneak peeks of upcoming boards which I'll be showing in videos and doing design walkthroughs of for this design I ended up choosing the esp32 C3 module reasons being that it includes Wi-Fi and Bluetooth in one IC but more importantly also for me I didn't want to use an external programmer or ftdi chip and nicely enough this C3 module has an inbuilt JTAG adapter as well as a USB to uart which means just with a single IC we're getting Wi-Fi Bluetooth JTAG and uart essentially via USB and an RF connection this IC costs about a dollar a dollar fifty a very small quantities so that's very powerful it's a 32-bit core running up to 160 megahertz with a couple of iOS we do need external flash memory and I'll walk you through that in just a second but this is the reason why I chose this IC in Autumn designer here's the project looking at the PCB first and I'll just give you a brief overview before we go into the schematic and then more detailed the PCB layout and routing the PCB itself is fairly small at approximately 40 by 25 millimeters we have the centerpiece which is the esp32 C3 module again including USB JTAG USB uart various gpios as well as our RF connection or if transceiver for Wi-Fi and Bluetooth my USB connection I've decided to go with a USB type-c connector which then we can also use to power this whole board keep in mind that Wi-Fi Bluetooth applications especially Wi-Fi can be quite power hungry so we want a fair bit of current handling capabilities or the buttons at the top left and right the top left is a reset button which performs a hard reset of this esp32 the top right if we hold this low and reset the board we'll put the esp32 in bootloader mode I've also exposed some additional uart pins which could also be just used as gpios as well as power and ground on the right hand side we have an inertial measurement unit therefore the name RF sense because we have an RF enabled board with for example inertial measurement unit meaning some accelerometers and some gyroscopes so maybe we can do some Sensor Fusion and then transmit that over via Bluetooth or USB or Wi-Fi for example now a small caveat with this esp32 2c3 chip is that it does not have very much or at all included flash memory therefore this device up here has a very small about two megabyte flash memory IC hooked up directly to the esp's 32c3 for program storage other than that of course has some ESD protection as well as a 3.3 odd regulator since we're getting 5 volts nominally from the USBC connector now most interestingly enough and for me what was the most interesting part of the design was incorporating a PCB antenna oftentimes you see these esp32 C3 modules pre-packaged so to speak for example you might be using one of these off-the-shelf modules which has got this little Shield can on it and underneath won't be the esp32 chips and flash memory as well as this black session at the top will be the PCB antenna now I thought it would be interesting to show you how to make this module by yourself so you don't have to keep buying off the shelf modules and maybe go for a slightly more professional board and I'll show you where I got this F inverted F antenna from how I did the impedance matching Network and what other considerations we have when it comes to PCB layout and routing but I hope this just gave you a brief overview of the board now let's go through in detail starting off with the schematic as usual when you're starting off with a completely new hardware design if you're going with st microotronics microchip or in this case esp32 it's important to always consult what the manufacturer suggests the esp32 nicely there some Hardware design guidelines and of course the data sheet for the esp32 C3 or whatever esp32 ICU end up designing for this Hardware design guideline is pretty much just what I've implemented in the schematic so I went through the schematic set checklist looking the power supply what flashes we need the clock sources RF sections and what gpios we won't need as well as then going later on to the PCB layout design I'll leave a link to this in the description below but this is essentially what I took and then implemented in my own schematic this isn't exactly the module we're using but it's received quite nicely gives you detailed schematics just to get the minimum system up running and this will exist for esp32 is C3 for the S Series and so on the schematic I made fits nicely onto one page it's grouped into the esp32 C3 section flash memory the PCB antenna USB connection as well as the auxiliary uart and the inertial measurement unit let's look at the esp32 C3 first and see what surrounding circuitry we need just to get this up and running I've been using the esp32 C3 data sheet and this gives me the pin out it tells me what all these pins are capable of you know some might only be for you art some might be for SPI some might be power and ground and so forth overall this is a 32 pin qfn package with an exposed ground pad underneath we'll call that pin 33 we have the various pin descriptions of the data sheet of course some of these pins they might be termed a crystal for example but they could be a gpio or an ADC for example so definitely consult the data sheet depending on your application for me I made this symbol so at the top I have my power connections and this device normally runs off 3 front three volts on the left hand side essentially have my digital sections were per pin I'm having about 100 nanofarads if decoupling capacitance as well as a larger in this case 10 microfarad bulk decoupling capacitor we'll see later in the PCB layout that these decoupling capacitors should be placed close to the relevant pins with the bulk decoupling capacitor should be should be somewhere in the vicinity oddly enough the naming is a bit odd because vdda actually isn't a specifically analog pin it turns out that vdd 3p3 so pins 2 and 3 are the RF section analog pins and these require some further filtering so we take our 3.3 volts we do some basic decoupling bolt decoupling filter it with this Pi Network so a CLC circuit looking like the Greek letter Pi and feed that into pins two and three this is the power source which is then used for the RF transceivers so for Wi-Fi and Bluetooth again C12 needs to be close to pins two and three on the other hand at the bottom of this IC so the ground pad from this qfm package is Simply Connected to ground on the left hand side we have general purpose I O so to speak on the right hand side we have the RF section chip enable as well as some Crystal signals let's start off with the crystal first we'll come to the PCB antenna later on because that's slightly more involved this specific IC the esp32c3 needs a 40 megahertz Crystal connected to pins 29 and 30. I chose a 40 megahertz Crystal and of course you need load capacitors and these are dependent on the load capacitance required by the specific Crystal you choose so the data sheet of this Crystal will give you specific load capacitance let's say nine picofarads we subtract the Stray capacitance and stray capacitance just do the packaging it could be the pads it could be the way we route our PCB and let's subtract about four picofarads so nine minus four is five we multiply that number by 2 which gives us 10 picofarads and this is then the low capacitance on either side of this these Crystal pins we need so low capacitance of Crystal minus tray capacitance that number times two is what I've chosen here you can also see R9 which is a 22 room series resistor and this is simply to limit the drive strength to this Crystal making sure we don't generate any excess harmonics and we don't overload this Crystal until we might get timing issues this is just a ballpark value in many cases you might not even need this resistor but not allowed to keep a series resistor in which I can play with in case I do have issues we could also optionally attach a 32k lower speed Crystal which might be for the real-time clock but in this case I didn't really need it so I've just left these pins floating or disconnected above the crystal pins I've put the chip enable and the chip enable is essentially our reset signal if we pull chip enable High which I've done default with this pull-up resistor to 3.3 volts this IC will start running once we bring power to the board I've also added a switch so a single pole single throw switch momentary switch we can pull down to ground and then this essentially resets the IC and this is useful for programming if you maybe have a fault on your system on reset the device and so forth before we get to the antenna let's look on the left side we have General purpose IO as well as our flash connections remember this esp32 C3 needs external memory in the form of flash memory and that is what I've done here we have dedicated pins grouped to the top pins 18 20 and this is this SPI interface so all I'm doing is rooting directly over no series resistor because actually the distance when we come to the PCB side is very short this memory I see I'm simply decoupling with with C6 again 100 farads close to pin 8 which is our VCC pin the power for this espar memory actually is not coming from the 3.3 volts it's coming indirectly so to speak through the esp32c3 pin 18 is a dedicated Power Pin which supplies power to the flash memory and this is maybe another little Quirk of this esp32 devices below that we have some general purpose pins so either we have JTAG but as I said before this esp32 C3 which contains a JTAG adapter to USB anyway so I've just used this as general purpose I O I've exposed some SBI pins some some general purpose I O for LEDs uart as well as pins 18 and 19 happen to be USB DN and usbd plus DP so the differential pair for our USB we don't need any series termination resistors we don't need to do pull-ups or so forth again all this information is listed in the data sheet so for example the USB D minus is GPO 18 and gpo19 is usbd plus pins 25 and 26. that's all I've taken over here indicated an Autumn designer this is a differential pair ESD protection straight to my USBC connector because this is USB full speed so not very fast at all up to about 12 megabits per second all I'm connecting is power and I'm connecting my DN lines together and DP lines together because of course this is a bi-directional connector I can flip the plug 180 degrees and I still want to maintain a connection with my ground connected Shield floating as this is a device and we only want the USB Shield to be connected at the host side which it is then we have this communication Channel pins so CC1 and cc2 and for USBC if we don't want to bother too much about negotiation all we have to do to Source current through this connector and from the host it connect the CC channels down to ground by a 5k1 resistors on each line so don't connect them together each individual line needs 5.1 kilo ohms to ground this is then also a power source which I provide some small filtering for a CLC Pi filter circuit and feeds in to this regulator this regulator takes normally 5 volts of input and I get 3.3 volts of the output C4 is my output bypass capacitor as well as this specific ldo this low Dropout regulator has pin 4 which we can attach additional capacitance to which lowers the noise floor the output of this device I've also indicated that we have about a 500 milliamp maximum capability from the specific ldo regulator which we'll need to power this board because the esp32 C3 can be quite power hungry note that I'm being a bit naughty to here because normally we should negotiate for 500 milliamp Max capability from the host right now I'm just pulling it without negotiation which is not technically to USB specs so that was the USB section again USBC connector provides power step down from 5 volts to 3.3 volts which Powers a whole board but we also have this USB differential pair on pin 25 and 26 which enable JTAG uart and so forth the other uart pins up here so twins 27 and 28 might be used to communicate with a different board or different device and I've simply exposed those on auxiliary uart header the additional SPI bus Which again taken from the data sheet which pins our SPI clock master in slave out and so forth I've hooked up to this inertial measurement unit which happens to be this Bosch bmi-055 I just have my clock data in data out chip select bypass capacitors decoupling capacitors again 100 nanofarads per pin pins 3 and 11 and various interrupt pins for example when there's a data ready signal from the accelerometer or from the gyroscope the gyroscope interrupt which is also on gpro 9 and leads us over to the boot mode selection g59 I've specifically indicated as well and this also goes to a pull-up resistor to 3.3 volts as well as a single pole single throw momentary switch where we can pull this low of course it turns out that this Super 9 pin is quite special it's the select bootloader mode pin if it's high which we saw from our pull-up resistor R14 this means it's normal execution mode the esp32 C3 will run whatever program is stored in Flash however if we want to reprogram this device maybe not using JTAG we have to pull gpio line low to ground and that's what we're doing with this momentary switch so we can hold the switch down cycle power or select the reset signal and then we put this into bootloader mode and that's why I've included it in this design finally now we're ready maybe to come to the most interesting part of this design and this is this inverted fpcb antenna we have a single RF interface connection for my esp32 device and this is on pin 1 and it's termed LNA in so low noise amplifier in this pin is both transmit and receive of course we want to transmit signals with Bluetooth and Wi-Fi and we want to receive signals so this is a bi-directional signal we connect it through this network and we'll go more into detail on this network into the second and why we need it in to this PCB antenna which is on the PCB side this rather odd shape over here and we'll go into more of the PCB design aspects later I could have simply of course just connected this to a UFL connector or some SMA connector and connect it to the external antenna but for the sake of size and for interest I wanted to add in a PCB antenna just to see will this work what is the performance how can we go around this and of course because it might make a quite nice little tutorial video nicely enough for me because I don't really have that expensive simulation software for RF designs and I couldn't come up with my own inverted F antenna I took an application note from Texas Instruments in this case application note an04 3 which tells us all about a small size 2.4 gigahertz PCB antenna at 2.4 gigahertz is normally the center frequency for Wi-Fi and Bluetooth at least for the case of this esp32c3 and this is why I was interested in this design and maybe taking this over to this esp32 dongle board this application node is quite nice it tells us a bit about the simulation what the performance of this antenna and so forth but also what the dimensions are of this antenna and this is most importantly for us what we need to do is take this design these measurements and essentially make a footprint or the copper outlines on our PCB using this so all I did was then take this information take these lengths and dimensions which are listed in this table and put them over into my own footprint and symbol in Alton designer what we then need to do is put this antenna on our board and connect this feed point on the bottom left via an RF Trace through a matching Network which we'll talk about in just a second into the LNA in pin of our esp3 to C3 module on the left hand side we also see we have a feed we also have a grounding point of this antenna which we simply tie to the internal ground planes with a via so just by copying this design of course this might not be accurately tuned and depends on the environment depends on what PCB materials you might be using how you've placed this we might get slightly shifted frequencies Center frequencies for this and different performances when we implement this on our own PCB in any case I made a schematic Library symbol essentially just drawing this up how it approximately looks pin one is my feed point which we saw from the application note by TI and pin 2 essentially my grounding point for this antenna then going over to the footprint editor these pad shapes here on the right hand side as went to the properties panel and entered these dimensions and then aligned these pads together to form this antenna another option to do this is also that TI provides a dxf file so a 2d drawing file for this antenna you can also import that into your own cut tool into Autumn designer keycad or whatever and just convert that to a footprint so that's how I included this PCB antenna so I didn't do any design work of my own I pretty much just took a pre-made design and of course hoping that this works on my own PCB which in the end it luckily it did if you're of course careful with how you implement it and we'll see why we need to be careful when we come to the PCB layout and routing in just a few minutes before that however we haven't talked about this middle section here which is the impedance matching network with RF antenna's transmission lines and so on we typically have nominal impedances typically we design around 50 ohms normal impedance and this antenna has an input impedance looking into it at about 50 ohms however looking at the data sheet to application notes for the esp32c3 in this particular package this pin pin one has an impedance of 32 plus J10 ohms now I won't be going to detail about impedance matching and what 35 Plus J10 ohms means but now what we need to be concerned about that this Z on the left hand side isn't the Z of the antenna if we don't match impedances we'll get Reflections we'll get power losses and which will ultimately degrade our Wi-Fi or Bluetooth performance and it could mean that this system doesn't work at all regardless if we've copied over the antenna correctly therefore this network of C15 L3 and c16 perform some form of conversion it's known as an impedance matching Network between the Zed or impedance on the left hand side which is the LNA in and the impedance of the antenna therefore the LNA pin or the esp32 will be happy because it sees the impedances wants so to speak very Loosely speak and the way we do that is by C15 L3 and c16 this again is a pi filter and this is impedance matching Network now there are many ways of calculating the impedance matching Network parameters so calculating what value of L We need c and the other C other capacitance depending on what source impedance we have and depending on what load impedance we have however you can just Google for pi matching impedance Network later there's also different types of impedance matching networks as well but I just went for this very simple pie matching Network let's remind ourselves The Source impedance is lnan which is 35 Plus J10 and our load impedance essentially antenna is 50 ohms our Center frequency is about 2.4 gigahertz or 2004 megahertz then I type my source resistance of 30 35 ohms Source reactants which is our imaginary part 10 ohms and then our antenna part is the load and that's just 50 ohms real we can play around with Q factors and so on but looking at the faults default results from this calculator we see we have an inductance of about two nanohenry's Source capacitance of five picofarads and a load capacitance about four picofarads what we see immediately is also that the source capacitances are very very low so five picofarads and four picofarads we can get there just with rooting bit of traces or having a slightly wider pad so effect these capacitances almost aren't there or they're negligible we can also change is the Q factor essentially around the center frequency how wide our matching point is how wide our bandwidth is around the center frequency and this again gives us different inductance values as well now the Q factor you have to determine depending on the bandwidth of the signals so Wi-Fi might have a fairly narrow bandwidth of a couple tens of megahertz and you have to adjust your Q factor adjusting to two we might get an inductance about 2.4 nanohenries a source capacitance is 3.4 and a load capacitance of about 2.7 3 picofarads again three and two picofarads are pretty much negligible they'll be part of the Stray capacitance anyway two might even have to include these but taking these values you can see these are pretty much the values I have here so I've rounded them to standard value components we're not going to get a 2.433 nanohanuary inductor not only are we not going to get that but we also have tolerances in these values anyway so it doesn't make sense to choose exactly these values especially for some fairly low frequency systems like this therefore I've rounded to standard values so I've taken 2.2 nanohare in the inductor and placed 3.3 picofarads before and after and this gets us in the right ballpark for this impedance matching Network here of course we might as well have to tune depending on what performance we get but without proper simulation tools this becomes very very hard indeed so this is a very good starting point and should definitely work and get us there again remember this is a not very high performance or high critical system in any case even if you're not going to calculate this is pi matching Network it makes sense to put it in any way maybe with just a short here and open circuits here as in do not Place Parts in case you might want to put some of these components down later in case you might need them so overall there are of course a few different aspects to this especially including this inverted fpcb antenna having to include the S Prime memory USB the regulator as well as some additional sensors and interfaces but now we've looked at the schematic let's move over to the PCB design now that we've looked at the schematic let's move over to the PCB design side of things now I'll give you a brief overview of the board of course the centerpiece is the esp32 C3 as well as the PCB antenna right at the bottom here but let's start at the top and work our way down so to speak this is a full layer board I have top signal and components as well as the bottom I don't have any components I just have rooted signals copper Paws and so on at the top side we have the USBC connector which again is power and our data connection goes through ESD protection with a differential pair our USB DN and D plus into the esp32 C3 we also have our power connection of course coming from the USBC connector going through this little Pi filter as we saw earlier into this 3.3 volt ldo regulator so input bypass capacitor regulator output bypass capacitor the power is then simply rooted and for a board like this low speed and even though it's an RF board we're going with analog RF and typically all analog RF boards have rooted power the there's no need to have planes for these kinds of boards most of my power routing happens on the bottom of this board you can see all these wide traces about 0.5 millimeters are all power rooted power internally I simply have two ground planes and this is really nice because anytime I need a ground connection I do a short wide connection from a pad and Veer myself down into the ground planes below to give me a really nice low inductance ground planes I have great references for the top signals and great references for the bottom signals due to having two internal ground planes the stack up itself is quite specific because I wanted controlled impedance traces for my 50 ohm Trace going from the LNA pin through the matching Network and then going to the RF antenna using Alton designers inbuilt impedance calculator for this specific stack up I'm using microstrip tracers to traces on the outer copper layers then I need about 0.3 millimeters to give me about a 50 ohm impedance control Trace in any case there isn't too much again to rooting this board we are of course slightly space constraint to my main principles as usual are as soon as I can I try to give myself clearance between relevant traces and also keep my connections as short as I need them be for example this esp32 C3 module down here I have the Q I have the flash I have the system flash above it very close so I don't need long traces and I can just simply root in all of my data connections clock connections on into the SPI flash memory same goes for this natural measurement unit short connections and the components placed so it makes my routing life a lot easier all I have to do is if I've done proper placement is root out into the relevant pins same goes for the crystal on the left which I've tried to place far away from any digital circuitry in its own little section decoupling capacitor placement as usual this is rooted power but what we always want to do is place our decoupling caps for example this one here close to the power pins of the relevant device short wide Trace is going to the pads and we simply dig down to the root power all the to the internal ground plane with short white traces and an appropriately sized via so all of these decoupling capacitors again close to the relevant IC short wide traces the usual principles always apply miscellaneous before we move over to the PCB antenna the top left we have the reset switch which is essentially connected to our chip enable and the top right momentary switch is connected to gp09 which was essentially our boot mode select switch we have the uart header on the left hand side with which was auxiliary uart remember we can use the USB connection for uart as well a couple of LEDs top right just as an on LED and just some generic G50 LEDs on the bottom right now let's finally move over to the most interesting part at least in my eyes which is the PCB antenna right at the bottom and reading application notes or guidelines sometimes can be quite confusing because they're sometimes contradictory information sometimes they don't tell you if you should remove ground planes underneath or how far you should keep a Json ground planes to the antenna and so on my guidelines and this is what I've worked and what I've gathered from various sources is as follows we have our LNA pin which is pin one of the qfn over here that roots with a very short Trace into our CLC Network remember this was our matching Network which we saw on our schematic what we always want to do with RF is keep our traces as short as possible unless we have good reason to do otherwise that's why I have a very short connection I'm keeping my capacitor the pad directly in line with this Trace inductor directly in line with the trace next capacitor pad directly line of the trace I could also of course move my capacitor like this and then do a little stub routing in here but what's the point of that we have then this little stub next to connection that's why for RF my suggestion is always place the pad through the trace also this transition for example from this Trace width which is a control impedance Trace to the slightly wider pad is not critical at all definitely not for these frequencies and when you think about how wide this or how long this pad is to the wavelength of the signal and you'll see that this is a minor minor blip and will not make any difference to the signal of course the higher the frequency is you might need to take care of this but at 2.4 gigahertz this is negligible anyway after we've come out of our LNA we go into that matching Network controlled impedance Trace now we're essentially at 50 ohms and I'm using a rounded Trace because it looks quite neat this is my RF Trace feeding into my antenna before we look at the antenna you can see I've also done a ground pour just to fill in the remaining areas of this board but around the RF Trace which is control impedance I've pulled the ground pour the copper polygon away from the trace so I don't mess with the impedance profile this is a microscip trace not a coplanar microscope trace and therefore it should be routed to such now going to the PCB antenna we have two connection points as well as we need to take care of our grounding and our general copper alignment around this antenna from this antenna Dimensions figure figure 3 of the ti application node it's pretty clear that under the antenna there should not be any ground pool on any layer so that's what I've done as well connection points we have on the left hand side we have our feed point which is our 50 ohm controlled impedance trace and on the far left side then we have a simple via to ground this is exactly what I've done here I've rooted my iPhone Trace in my feed point and on the left hand side we have our grounding point and that's all there is looking at the Copper view layer 1 below there's no copper no ground Port underneath antenna layer 3 and layer 4 either so as soon as we reach that point again just following this application node we have some copper underneath the feed point in the Via to ground but then we stop after this distance D4 which is given in the table here 0.5 millimeters so this short distance 0.5 millimeters still has ground underneath it but then we abruptly cut that off and then leave it to our PCB antenna I've also added these cutouts into the board here just to make sure I'm not placing anything no copper near this antenna as it should be again these dimensions of the antenna was from the footprint again was from the ti application node and that's pretty much all there is to incorporating this PCB antenna into this design now I've hooked up this esp32 dongle to my computer just via USBC cable and let's use the Arduino environment because it's really straightforward to set up with esp32 ICS and give this a little test doing a Wi-Fi scan I'll definitely make some more detailed videos on the feature how to play around with this esp32 how to program it but for now let's just look at a very simple test so I've installed the Arduino IDE which is freely available and I've installed the esp32 packages which also come with various examples you can use Wi-Fi scans and we can check out many of the different peripherals including Wi-Fi what I've done is scrolled the bottom of the examples Wi-Fi and then I've opened the Wi-Fi scan example now this is a private example I haven't changed anything with this and all we're doing is listening for Wi-Fi networks and listing their ssids this is really useful for us to test you know that we get some sort of RF signal coming through our PCB antenna that we can program the esp32 C3 and they're generally are Hardware somewhat working so I've not modified the code at all before we upload the code to the board we have to select what board it is and because this is a custom board I'm just going to be using some generic prototype board that's available on the Arduino IDE that happens to be the esp32 C3 Dev module variant if we look at the other boards there are many boards from different manufacturers but this fit my Hardware specifications the best so that's why I chose it then my port I've plugged in my module it's detected it on com 8 it's given it a wrong name but this doesn't really matter as long as it detects it on a Serial port and remember this esp32 has natively JTAG and USB uart built in I don't have to have an extra separate IC so this is really nice I just connected to the USB pins of the esp32 module what I do need to change however is USB CDC on boot we need to do that enabled and this is because when we're using the serial.printline feature we don't want to print on a default uart we want to print via USB so to speak very Loosely speaking CPU frequency I've left on maximum debug level I've just changed to verbose so we can see see what's going on flash frequency you have to set a 40 megahertz flash mode it's quad SPI The Flash size for this specific board is 2 megabytes others the default is usually four megabytes for this one I just went with two JTAG adapter integrated USB J tag partition scheme just because of the smaller flash I just went with minimal and upload speed 115 200. default is 91 600 in this case it doesn't really matter then all you have to do is Click upload wait for the sketch to compile and then it'll start writing data which is really a great sign that something is happening and you can see the flash as well now because this board doesn't have an RGS pin I just have to manually reset by pressing the reset button I have to reselect my port because we now reset the device and open the serial monitor the serial monitor now we're showing it's booted up because we put it into verbose mode we've loaded from the flash memory now it's we're scanning so we can see because of the roast mode a lot of different messages but most importantly if you look at all our serial print line commands we have Scan start and what networks it's mining so scan start we already see the USB yacht is working the JTAG was working but we are also finding different networks which means something must be right with the antenna design of course you still need to check bandwidth and so on but for this video it's just a very generic indication my awfully named Wi-Fi is actually called cheeky wifi in that and this is my main Wi-Fi in my home and the PCB antenna is picking that up quite nicely is the strongest signal and then some neighbors seem to have different sometimes German name Wi-Fi ssids over here as well so this is a great indication that we can program this device and that we can indeed do a tiny bit of stuff with Wi-Fi The Next Step then in a future video is to then really check out the capabilities of this PCB antenna checking bandwidths and so on if we just do a quick Google search for RSSI they've also received signal strength indication levels we can see the units are dbm which we're also seeing on the right hand side in our serial Monitor and for my Wi-Fi where my routers pretty close a couple meters away we're getting -66 CBM it's for fluctuating a tiny bit but as a general indication this site is saying -67 dbm which is pretty much what we're getting is a very good signal strength for Reliable data take this with a grain of salt and we'll do some more Wi-Fi tests in future videos so definitely stay tuned for those thank you very much for watching this video I hope it is useful and I hope it gives you some incentive to try making your own esp32 based designs and maybe including your own PCB antennas into them as well if you like the video please do leave a like if you want to of course subscribe to the channel there'll be many more esp32 videos to follow especially on the firmware side where we now get to program this board test the Wi-Fi capabilities and much more thank you again for watching and I hope to see you in the next video bye-bye

Channel: Phil’s Lab

Views: 102,852

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Id: yxU_Kw2de08

Length: 34min 6sec (2046 seconds)

Published: Sat Jan 07 2023