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winiak / LoRaRC

LoRa for Remote Control
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Raven Long Range System #4

Open SwiftFlying opened 6 years ago

SwiftFlying commented 6 years ago

Hi, I am very interested in LORARC. I would like to support you on the hardware. You can refer to the RavenLRS code so that this project can be developed rapidly.

winiak commented 6 years ago

Hello SwiftFlying, Thanks for the hint of RavenLRS - I was not aware of this project. Do you know about any proven flight using this system? I will be happy for support in HW. I don't have much time to work on it also. I was thinking about making small board (16x20mm) to solder RFM95 on one side and Atmega on the other side of the board. Then split the rest as convenient. The only connector would be JST to have both: PPM and UART there. Another variant would be a board with mounting holes like Flysky FS-X6B - to mount it on top of FC. There would be some more space for power supply filtering - usefull in drones ;). I was thinking about https://easyeda.com to make it Open and easy to order. Looking forward for your opinion.

SwiftFlying commented 6 years ago

I can design two PCBs, one TX (mounted on FRSKY X9D) and the other RX, which may use MEGA32U4 + SX1278+PA.The TX module has Bluetooth and OLED.Need to support telemetry function。The RX module can use 2PCS SX1278 to make diversity. https://github.com/DzikuVx/QuadMeUp_Crossbow https://github.com/RavenLRS/raven

SwiftFlying commented 6 years ago

Hi winiak, MEGA series IC may be difficult to meet the requirements, preferably using STM32F103, ARDUINO can support it. What's better now is frsky R9m and TBS CROSSFIRE.Many users are interested in LRS now. We can find some pilots to test it. This project takes more time, and you may not have enough time to develop this project. If you have time, I can make 2 sets of prototypes，And send you debugging.

winiak commented 6 years ago

Hi SwiftFlying, I would like to avoid making that significant changes to the project at the moment. The main goal is to make it as simple as possible. Having dedicated PCBs is a profit - for sure. But still it should be compliant with "sandwich" of Arduino and RFM95 soldered together. There will be a build log in next few days. In addition, building a big project like R9m or TBS is a hell of work. I'm not able to reach such targets. Anyway, there are already projects (like Raven) with sophisticated goals, let them do. For the record - I like the idea of using STM instead of Atmel - STM has better EMC results and 16MHz generator in Arduino has some harmonics in 868MHz area but still Atmega is good enough for the moment and in case of form factor - development board is smaller :).

Still, with Arduino and RFM95 we have a decent range (I reached 5,8km at 10mW, video link was the limit) and small latency (25ms) - both can be improved (not at the same time). There is a capability for Telemetry (RSSI, GPS coords, Voltage, etc) and even injecting Waypoints during the flight. All that for $6...8 per module. Let's do it in small steps. It is already proven (in flight) project.

Regarding RX with 2pcs of SX1278 - I think it's not efficient. SX1278 is supporting diversity in one chip by design. Both TBS and R9m are using it in their design. Take a look on the cost of R9m receivers - $15 :).

How about having a variant of board that has 32x32mm size (to assembly with FC) and use the same in FRSKY JR module housing?

SwiftFlying commented 6 years ago

Hi winiak, The size of 32x32mm is enough.I need to integrate a 3.3V 1.5A BEC.even injecting Waypoints during the flight,This is very good.I am familiar with FC hardware.

winiak commented 6 years ago

Hi, I recommend linear voltage stabilization down circuit. It will be supplied from 4,5 (FC supplied from USB) to ~5,5V. I'm using AMS1117 for a long time with different radio modules.