915 MHz LILYGO T-Beam-S3Core 22/11/02 V3.0 w/GPS IMU etc.

[arizonajon1]

Hey Ricardo -

I just received one of these in the post. For a tracker, which firmware build is appropriate?
Also, there are two USB-C ports on this thing. My PC does not seem to recognize either as it does the other boards I've acquired.
Cheers and 73 - Jon N7UV

[richonguzman]

this board is T-Beam Supreme (ESP32S3)

the trick for ESP32S3 boards is to press BOOT, dont release boot!
press reset, release reset and then release boot

and then you are ready to flash it

[arizonajon1]

It acquired GPS lock, but there's no blinking LED showing the 1 pps. So it was hard to tell that it had acquired. It is configured as N7UV-8, and shows up on aprs.fi.
What I notice is that there are no telemetry packets. The display is showing "weather" (pressure, temperature, humidity) and battery voltage, elevation above reference geoid, speed, etc.
Is there (yet) a way to configure it to transmit telemetry packets? Or, can it transmit weather packets? I didn't see either of those options in the configuration menu.
Muchas gracias, Ricardo! (oh, I sent you some money in case you want to get one of these)
Cheers and 73 - Jon N7UV

[arizonajon1]

there are no LEDs active at all on the board. No tx, rx, GPS, etc. I suppose I will have to use the I/O ports to put in some LEDs to monitor it.

[richonguzman]

not all GPS have blinking led to show fix.

check: https://github.com/richonguzman/LoRa_APRS_Tracker/wiki/02.-WebUI-Tracker-Configuration#wx-telemetry for the Telemetry packets over RF.

Thank you Jon for this !!

[richonguzman]

there are no LEDs active at all on the board. No tx, rx, GPS, etc. I suppose I will have to use the I/O ports to put in some LEDs to monitor it.

you can add this with the notifications part of the web config (but you'll have to test if the pins are working empirically

[arizonajon1]

I did enable all those. Here's a run I just did to the grocery store, and the track is pretty solid.

For the 3 different scenarios (low speed, mid speed, high speed) you have provided for selection, can you tell me what are the time intervals for each? I see "Smart GPS" or similar, is that like "Smart Beaconing" which adjusts the GPS message rate based upon speed, heading change, etc? Can you expose those to allow customization?

While I understand you don't want people to overwhelm the radio channel by beaconing GPS too often, is there a way you can make a version that would transmit a GPS beacon in specific intervals (like 5 seconds or so) so that I can drive around and know that I should be sending a beacon? I'm on 927.500 MHz and there's nothing else on the channel.

Also, I do see wx values, but it's very infrequent. Maybe once every 30 min? I would again like to see the wx more often, just to experiment better and to understand the radio channel and propagation. Again, there's nothing else on this frequency. Only the three values (temp, pressure, humidity) are used. Interestingly, battery voltage is transmitted as a telemetry packet, which is different from the wx packet, so for the wx packet can you add battery voltage as the 4th value in wx telemetry, or does that break something?

The LilyGO Supreme has a bunch of i/o and analog input ports, and it might be fun to be able to transmit some of those as telemetry.

I don't know if you are aware of what Mateusz at Microsat does, but he allows the operator to populate the telemetry values with things like "packets heard, packets heard and decoded, packet digipeated, packet reception efficiency, which can be helpful for a digi. Check out my digi ARSTRA in the western part of Arizona. Unfortunately, I didn't enter the values for the DS18B20 thermometer correctly so it always shows zero %^(

Finally, I have advertised the 927.5 MHz LoRA igate/digi on my 2m APRS channel as a special beacon that transmits over RF every 20 minutes. I'd like to find others in the area who might be interested in giving it a try.

Salud and 73 - Jon N7UV

[richonguzman]

the smart beacon info is like this:
https://github.com/richonguzman/LoRa_APRS_Tracker/blob/main/extra/turn_slope_calculations.xlsx

5secs between packets will block fast when more trackers use the same freq

I recommend no less than 12 or even 20secs between packets (how much gps points do you really need? )

can you elaborate a little more about the required telemetry you wrote?

[arizonajon1]

looking at the RAW log on aprs.fi, looks like wx transmits every 10 minutes? That's fine.

[arizonajon1]

I notice the wx temperature data shows in F, not C. Is that a configuration function on my part?

[arizonajon1]

another thing I notice is that the telemetry packets appear to stop sending when the device isn't moving any more. Or is that another configuration function I missed?

[richonguzman]

I notice the wx temperature data shows in F, not C. Is that a configuration function on my part?

raw packets must be sended as Fahrenheit (but any app or webpage can translate those to Celsius)

[richonguzman]

another thing I notice is that the telemetry packets appear to stop sending when the device isn't moving any more. Or is that another configuration function I missed?

when you move WX packets wont be sended

as Wx packets should be Weather "real" data and not any custom data which could be sended as "other" telemetry

[richonguzman]

now I get what you were talking about.

those telemetry data could be builded also, but right now those values are not generated (but I can build it)

this type of telemetry is it really needed? I mean, you can see and decode and test all with syslog info unless those stations are digipeaters without any internet

[arizonajon1]

most of our digis are in very remote locations where even cellular is sketchy or missing. And cellular adds a monthly cost to be able to monitor. At our really remote sites, we use the Microsat PLXDigi which can encode those data as telemetry. It's certainly not needed if there's an Ethernet connection, as you point out. For now, given that there's no one locally using LoRA APRS 900 MHz, that kind of telemetry is not useful.
I think the analog telemetry is more interesting. I haven't looked at the ESP32 yet to see how much resolution it can provide.

[richonguzman]

lots of resolution, what exactly do you want to measure?

tracker and igate has currently "internal Battery Voltage" and "external Battery voltage"(with voltage divider) encoded telemetry

so all can be used for sure

[arizonajon1]

the ADS712 family of hall effect linear current sensor chips have outputs in the 66 mV/A to 185 mV/A range. It would be nice to be able to read values with a resolution of <= 6 mV so that even with the 66 mV/A devices I could still see 0.1 A resolution.
They're neat chips, a bit clunky and finicky, but fully dc-isolated from the current being measured, so there's no weird voltage loops that happen. Just feed the current you want to measure through the sensor leads on the chip and 0 to 5 volts comes out the other end. 2.5 Vdc is zero amps, so the device can read current bi-directionally. I have some that are +/- 5 A full scale and some that are +- 20 A full scale. Makes it easy to read current.

[arizonajon1]

Going back through this convo, I understand the need to not mix "telemetry" with weather data. The weather packet format has been stable for a long time, so I understand not to make non-standard.

However, I think telemetry should be sent at all times, not just when a device is moving. Let's say you have a balloon, when it falls to the ground you still want to know how much battery it has left before it stops transmitting. For me, since my sites are generally without internet, I need to know the status of the battery, the charge controller, the temperature of the battery, etc. I hope you can modify the telemetry to send always at a constant rate, or at least make that an option in the configuration.

I think the ESP32 has a 12-bit ADC resolution. At 3.3 v max input, that's 0.8 mV per step. That's completely sufficient for the hall effect linear current sensor chips. For the 5 A version, that's a resolution of 12 mA of current.

Given there are 5 possible telemetry channels available, for my remote sites I'd like to see

Vbattery
Tbattery
Ibattery
Packets decoded over the last 60 minutes
Packets digipeated over the last 60 minutes

I'm sure that others may prefer different. However, the 3 analog inputs above can be supported by 3 available analog inputs on the processor.

There may be digital bits that someone may be interested in. To date, I have not used the digital telemetry bits, but maybe now I will, I could use one to determine if the room/enclosure where my digi equipment is installed has been opened! Maybe I'll put that on my next digi build.

[richonguzman]

I guess I will have to add a telemetry menu for this:

With name , units, value, input pin, voltage divider values

Will have to check how much pins are available and how to add this

[arizonajon1]

I just ordered a 900 MHz tx amp/rx LNA from Ebay. 30 - 36 dBm out, 1.5 dB NF (not great).
SZHUASHI 100% New 4000mW ISM Bidirectional 915MHz 35dBm Wireless Power Amplifier
Let's see how well this amp works.

[arizonajon1]

i know. However, the 902-928 MHz noise floor is very high, much higher here than in licensed bands. Like having a TV station 100 km away... Nonetheless, we do the best we can.

[richonguzman]

let me know how your heat map turns out (maybe to compare how 915 works instead of 433)

any message app you use? like Telegram?

[arizonajon1]

I use signal. Gotta remember my username %^)

[arizonajon1]

I think it's "the abominable dr phibes"

[richonguzman]

the abominable dr phibes

write me at my "github username" + ".73"