Thread Tools
Nov 08, 2019, 05:38 AM
Registered User
good job

can you show me photos ab out infor telemetry ,it work with opentx?
Sign up now
to remove ads between posts
Nov 08, 2019, 05:26 PM
Registered User
Current TLM shows RSSI, SNR, LQ.

https://github.com/AlessandroAU/Expr...2_main.cpp#L85
Nov 09, 2019, 07:30 AM
Registered User
Micron RC's Avatar
Hi

Any plan to publish the receiver PCB? I would love to try this out.

-- Andy
Nov 09, 2019, 07:35 AM
Registered User
Thread OP
Quote:
Originally Posted by Micron RC
Hi

Any plan to publish the receiver PCB? I would love to try this out.

-- Andy
Yep, waiting for my order from JLC, after testing to make sure there are no errors I will publish the Gerber files
Nov 10, 2019, 02:43 AM
Registered User
Some weekend test data!

Below are screen shots of BB logs for CRSF (100mW) flying alone, ExpressLRS (50mW) alone, FrSky alone, and ExpressLRS with 2 other quads (ExpressLRS and CRSF). None of the screen shots have been cherry picked and the RC Smoothing Rate spikes are consistent across the entire flight,

Impressions are that the rate changes have little to do with packet loses when flying alone, and more to do with Betaflight ingestion (happy to be corrected here).

When flying together you see an expected LQ drop due to collisions.
Nov 13, 2019, 01:40 PM
Registered User
Nice Job Guys, a solid open link and Open software would be the future, possibly it could be picked up and we can have several sources for hardware.

Could also be interesting to look at LORA 2.4ghz such as SX1280 modules, there is more bandwidth at 2.4ghz for races and antennas can be smaller, the LORA gain should increase range compared to tradional 2.4ghz link. (I expect it is also what Flysky AFHDS 3A is about...)
Not real long range system, but fast and good open system.
Last edited by fernandez; Nov 14, 2019 at 06:08 AM.
Nov 14, 2019, 08:30 PM
Registered User
Quote:
Originally Posted by fernandez
Could also be interesting to look at LORA 2.4ghz such as SX1280 modules
It would be interesting to do but I believe the over the air time is the same as the sc1276 etc. It might be better to keep the packet protocol and use the cc2500 (and now we have FCs with integrated Rx). Bryce with Redpine is showing that you can get very fast (aiming for 1ms) protocols on 2.4GHz.

But on the topic of FCs with integrated receivers... I would love to see a FC with integrated SX1276! Imagine being able to select your LoRa protocol from within Betaflight! ExpressLRS for racing, or RavenLRS for long range.
Nov 16, 2019, 12:21 AM
Registered User
Some more blackbox and RC link data

This was taken at a local race event flying with other quads in the air and who knows how many other transmitters on in the pits. ExpressLRS is set to 200Hz, 50mW, and TLM packets every 64 packets. The below image shows TLM packets in red arrows, sync packets in blue, yellow is TLM and Sync one after another, and green are missed packets.

All in all it looks pretty good IMHO
Nov 17, 2019, 11:38 AM
Stuart
srnet's Avatar
Quote:
Originally Posted by fernandez
Could also be interesting to look at LORA 2.4ghz such as SX1280 modules, there is more bandwidth at 2.4ghz for races and antennas can be smaller, the LORA gain should increase range compared to tradional 2.4ghz link. (I expect it is also what Flysky AFHDS 3A is about...)
Not real long range system, but fast and good open system.
Your so right, the SX1280 is capable of much higher data rates than the SX1276. With the SX1280 even at the max LoRa rate of 200kbps you should get circa 4km ground to air with simple antennas. Then of course there is the SX1280 FLRC mode which should give around the same range but at 650kbps.

The fastest standard LoRa devices can go is the newer SX1261\62, these can do a 16byte packet in 2.5ms. An SX1280 in FLRC mode can manage a 16byte packet in 0.27ms.

The realtivly high bandwidth of LoRa can create issues at 434Mhz where there may only be 1-2Mhz of bandwidth available for legal use. At 2.4Ghz, here in the UK there is 83Mhz of bandwidth available.

Read about my adventures with the SX1280 here;

https://www.loratracker.uk/blog/
Nov 18, 2019, 12:52 AM
Registered User
Quote:
Originally Posted by srnet
The fastest standard LoRa devices can go is the newer SX1261\62, these can do a 16byte packet in 2.5ms.
How did you come to 2.5ms? Measured? Using the data sheet I get 2.4ms for 8 byte packet.
Nov 18, 2019, 05:22 AM
Stuart
srnet's Avatar
Quote:
Originally Posted by hbgsrjnyrmeBHT
How did you come to 2.5ms? Measured? Using the data sheet I get 2.4ms for 8 byte packet.
I was using the Semtech calculator .............. not sure now where the 2.5mS comes from, the calculator now says 3.9mS.

The fastest a SX127x can manage the 16bytes is 6.2mS.

And with the SX1280, which was the subject of @fernandez comment, you could by turning off FEC, persuade the SX1280 to send an 16 byte packet in 0.154ms and an 8 byte one in 0.105mS.
Last edited by srnet; Nov 18, 2019 at 05:38 AM.
Nov 19, 2019, 04:36 PM
Registered User
This would be a nice module of interest. Very small and diversity and then implement as SPI RX in Betaflight.
https://www.silicontra.com/UploadFil...4;书.pdf
https://www.aliexpress.com/i/33010895957.html
Nov 20, 2019, 02:26 AM
Registered User
Quote:
Originally Posted by fernandez
This would be a nice module of interest. Very small and diversity and then implement as SPI RX in Betaflight.
I suggested this in the BF slack https://betaflightgroup.slack.com/ar...73549152197800

It would be very cool to have an sx1276 or sx1262 (this guy is only 4x4mm) on the FC. You could then have the ability to select your preferred LoRa protocol from the Configurator e.g. ExpressLRS, Raven etc.

Any vendors out there want to collaborate
Nov 20, 2019, 08:56 AM
Registered User
Yes but 433 and 868 antenna are big, fragile, heavy on micro etc. Also with many racers flying simultaneously in close proximity 868 band (small) we may face packet loss. It is nice for long range option.
For racing Lora at 2.4ghz, it seems will be able to improve range ad update rates.....(and keep small antenna)
Dec 05, 2019, 02:28 AM
Registered User
Woot, received my 16.5*21mm Rx PCBs today. Everything is looking good on the bench and will be flight tested tomorrow.


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
New Product QCZEK LRS - DIY 433MHz 1W (30dBm) LORA RC LINK with telemetry qczek DIY Electronics 3406 Yesterday 02:57 PM
Discussion Anybody interested to develop a LoRa based Tx Protocol? courcirc8 Radios 8 Jun 07, 2018 03:01 PM
New Product FPVmodel X160 Pro FPV Racer (Optimized Based on DYS X160) FPV.Model Mini Multirotor Drones 5 May 28, 2016 09:19 AM
Discussion DIY Telemetry System base on TI CC110L RF BoosterPack spy004 DIY Electronics 2 Mar 06, 2013 08:58 AM
Discussion Tucson schools create race-based system of discipline MtnGoat Life, The Universe, and Politics 8 Mar 16, 2012 01:22 AM