Beacon Parameter Optimization Guide | Marvelmind

0:02 Hello, let me explain now in more detail the menu on the right, which are parameters of radio interfaces. Let me explain based on the beacons, not on the modems, because radio settings are more or less the same for beacons and modems, but in beacons there is also ultrasound. So let me explain based on the example of beacons. If I press this plus, it expands. What I have is base frequency. Base frequency is sort of a base frequency against which channels are jumping. So channels give me—you see I'm jumping, base frequency doesn't change, but the carrier, the resulting frequency will be different. Another important element is the radio profile. Radio profile you can

1:01 choose between currently three preset radio profiles. For you it's important to remember that 500 kilobit per second gives you the fastest update rate, but the bandwidth will be the broadest and the sensitivity will be the least. And it means that if you have some external interference, your system will be most vulnerable with this radio profile. But at the same time, the update will be the highest. So it's important if you have copters, for example. But if you need longest distance in radio, then obviously 38 kilobit per second is recommended. Okay. Now I made the classical mistake, because the system will be now very difficult to wake up because I changed the radio profile. Now I would need to

1:59 change the radio profile on the beacon and on the modem as well. So I will go here. I will write it all. And now I will return to this and try to wake it up. Yes. Now I see it, because you see it's 38 kilobit, but all the rest is on 500. So let me change it here. Write it all. So now it's again on 500 kilobit, but I will lose it very quickly because the beacon, the modem is talking on 38 kilobit. So let me return back everything to 500 kilobit. So now the system is supposed to be working. Okay. Let me try to read it. So at least it must work now. You see I'm checking

2:59 their status. Okay. Okay. System is back. I'm checking based on time from the reset. When the time is ticking, so it means that the system is active, and this one. Okay. So time is ticking, so this beacon is also active. So everything is fine. But you see what I did. I basically switched the radio profile. And as soon as I switched it, if I do it quickly and it doesn't record, then it's still okay. But if I wait for a couple of seconds, then radio profile settings, the new one will be automatically written to beacon 6. And since that beacon 6 will not be able to talk to the modem anymore because the modem will be talking to the beacon based on radio profile 500 kilobit per second, and the beacon will be listening

3:56 based on 38 kilobit per second, and they become absolutely incompatible. So be careful with this. This is why if you lose the beacon due to radio or due to some manipulation, don't worry. Just take the beacon, connect it via USB to each of the beacons, press default, and all of them will move to the default settings, and you will always be able to find them. So don't worry about that. But at the same time, be careful with the settings, because as soon as you click it and keep it for a couple of seconds, then it writes the new radio profile, which is different from the modem, and then the modem will lose this beacon. So remember what you do or don't do until you know. The device address, which was discussed already. The device address is basically the name of the address or number of the address. Without knowing it, you cannot talk to this beacon. You cannot wake it up. You cannot do anything with

4:54 the beacon. So you must know the device address. Channel. There are several channels. So currently there are four, but there will be more. It's basically channels, so you can set up several systems, and the systems will not know that they coexist. They will basically operate on absolutely separate frequencies. So it means that if you have two systems, two modems can run them, but remember that they will not know about each other in radio. But in ultrasonic, they will interfere if they are in the same room. So be careful. You can deploy in different rooms where ultrasonic signal doesn't propagate from one room to another. In this case, two, three, four systems can coexist very easily. It's also important: if you have interference in one of these frequencies and you cannot move that interference, you can move yourself, change the channel, and move to

5:53 another frequency where there's no interference. Modulation. Once again, this radio profile is a combination of different settings. This modulation, we chose maximum power. Spacing—you don't need to do this at all, so just don't touch it. This is some internal stuff. You don't need this. You can of course play with this, but you must have the same settings on the beacon and the same settings on the modem, otherwise they will not be able to talk. But for simplicity, this is why we combine them into the radio profiles, and the radio profile automatically chooses all these. So don't touch it unless you really want to go very deep into the radio interface. Another very important part is ultrasonic. So in ultrasonic there are also quite many settings.

6:52 First of all, mode of work. TX normal is the normal beacon settings. There are some internal settings. TX only. In this mode, the beacon is emitting pulses of five periods each, eight times per second. It's basically clicking eight times per second. RX only. It doesn't limit anything. It just listens to it. Again, it's more for internal debugging. Channels 8 hertz. I frankly don't remember. It's something deeper. I think it's switching this one. So don't worry about this. This is the mode, TX RX normal. This element is sleep mode. By default it's now enabled, and this is why the system is not so optimal in terms of power consumption. You can disable it, and it will

7:48 be far more power consuming or less consuming in sleep or in deep sleep. But be careful because we played with this a lot, and maybe this feature is now disabled, so I don't remember. Part of the transmission again—some internal stuff. This is what you need to know. This must be in this mode. Don't play with this. This is internal. This is frequency, basically the central frequency of ultrasonic. We are using customized ultrasonic sensors, and the central frequency of those sensors is 31 kHz. It can be different, but what you are getting now in Beacon HW v4.9 is 31 kHz. Duty—it's basically a meander, so it means that one and zero are equal, so this is why it's 50. But you can set it differently. In this case, you can play indirectly with the amplitude of transmission. Usually it doesn't affect much, but you can play.

8:47 Duty cycle can be different. Number of periods—this is important. So when you have a small room and you want the least echo, and you want again in a small room, use a small number of periods, like one to five. It's for a small room of, for example, five by 10 meters. But when you have large distances or a large room or a large corridor of 30 or 40 meters, just type whatever 30, 40, 50. If you go above 50, usually it doesn't help much, but if you go from five to 30, you will certainly see that the signal will be much stronger. So by 10 meters it's not necessary because even five is more than enough, and even smaller than five is enough. But when you have a large

9:45 Distance of 30 m, 40 m—I would recommend to move it to 30-40. Number of periods: this is for the self-calibration. You can set amplification AGC, which is recommended, but you can set it manually. This is important when you have some special conditions, or very special conditions—for example, very noisy copter flying above the sensors. So AGC may be suboptimal, so it's recommended to move to manual and then set receiver amplifier to some manual settings. Play with it. It's very nonlinear, so if you change from 100 to 200 or from 1,000 to 2,000, it doesn't mean that the gain changed two times. No, it's very, very nonlinear. It doesn't change until some limit, then it changes very quickly, and then again it's

10:42 Pretty flat. So play with it. Use the oscilloscope to see the signal. But choose it. So this AGC setting is more or less internal stuff, pretty complex. So you don't have to play with it unless you're really aware what you are doing. So some internal stuff about the settings—keep it like it is by default. It's about EGC settings. It's about threshold mode. So for you, not much here except for this AGC versus manual. By default, AGC is recommended, but for some special cases, yes, you can play with manual settings, or actually, it's even very much recommended to play with manual settings. Here, by the way, you can also set manually any of these, and it is important and it's useful when you have some special

11:40 Conditions. Once again, special conditions means very noisy environment—by copter or by external noise. You can reduce the gain such a way that you would achieve the highest signal-to-noise ratio, because if the gain is too high, the noise will be amplified but the signal will be saturated and signal-to-noise ratio will be poor. So reduce it to 200, whatever—200, maybe even less than 2,000—for each of these. Monitor signal in the oscilloscope. So maybe it will work even like this. So let me try. Maybe it will work. Okay, like this example. So this is a good signal. You see there's almost no noise and the signal is pretty strong. So there the system operates well. But when you have

12:40 Too high noise, noise will be amplified but the signal may be too strong and the signal is saturating, and the signal-to-noise ratio will be poor. And the solution is reduce the gain. In this case, both signal and noise will be reduced, but signal-to-noise ratio will be improved because the noise will be reduced but the signal will not be saturated anymore. So it means the signal-to-noise ratio will be better. So play with it. Okay, back to radio settings—don't need ultrasonic. So gain is important. What else? This is also internal stuff, very much internal about AGC settings. You don't need it. The only thing you really need is this RX1 settings. Check the manual. In your beacon, there are five sensors: RX1, 2, 3, 4,

13:39 5. Four is the central sensor facing straight. So this is up, et cetera. So what's how it works? Because it works this way: if I choose this one, and I disable some of them, check. You see the signal. Okay, then AGC kicks in. AGC again reduces the gain. But what first you see? You first see that the gain drastically increased. Actually, the signals drastically increased. Why? Because RX1, RX2, RX3 doesn't necessarily receive the good signal, but it loads RX4, which is receiving the good signal. It's basically the load for them. So it means that if you have

14:34 RX4 facing your mobile beacon but RX3 is facing some other direction where mobile beacon must not be or will not be, just disable it. So that will be the most optimal. So this is important for you. And there's a difference between RX normal and RX frozen. Sometimes it's important to set with RX normal. RX normal mode means that when you set up the map, and RX frozen is when the map is already frozen. For example, beacon 10. Beacon 10 is facing all other beacons. And if you position the beacon like this and beacon 4 will be looking this direction, beacon 4 having around 90° angle is sufficient to cover all this territory

15:33 Because it will be facing like this. You don't need to enable other beacons because one beacon will be looking this direction—there's nothing. This direction, there is nothing. Bottom, there is nothing. Up, there's nothing. So beacon 4 is generally good enough for this system. At the same time, for this beacon, beacon 4 may not be enough because, sorry, sensor 4 is not enough because beacon 13 is looking this direction. But at the same time, this is on the left, this is on the right. So it means that you would need to enable sensors RX1, RX3 if they are looking this direction, because otherwise you will not see them. But this is during the map building. But at the same time, if you have your copter flying only in this area and not flying to this area, then you don't need beacons here in RX

16:32 Frozen mode. So it means that for beacon 13 in this case, I would probably choose these settings: I don't need beacon sensor five, I probably don't need sensor two—five is looking upward, two is looking downward. Beacon four, sensor four is looking straight, this is looking left, and this is looking right. So I return like this, but in the frozen mode. If my copter is flying only in this direction, I wouldn't need this sensor and I wouldn't need this sensor, and I disable them, leaving only this sensor. So it's pretty advanced, but it gives you the most optimal settings. So when you build the map and you don't have noise, you use three sensors looking this direction, looking this direction, and looking this direction.

17:31 But when you freeze the map, you use only the central sensor. But keep in mind that in this case, this area will not be served and this area will not be served. If you expect that the copter will be flying this or robot will be moving this, then you need the sensors as well. If you expect that your beacons will be serving all areas, then of course enable everything. So by default, everything is enabled. It's not the most sensitive, but at least it guarantees you the widest coverage in ultrasonic. But at the same time, it means that you can collect noise from all the directions. For example, if you have some source of wideband noise this direction, it's much easier if you just disable the sensor looking this direction and thus improve signal-to-noise ratio drastically. So that was about ultrasonic

18:29 Settings. For you, most important is this mode. This—don't touch. This is important. Sometimes gain is important, and this is important. So interfaces—it's the same. Speed protocol for SPI and raw data. So you can get the raw data from mobile beacons, not stationary beacons. Some mobile beacons are coming with EMU installed, and you are able to get the raw data out of them. So that's it for settings in the Dashboard. If more, just ask your questions on the forum.