Motor winding adventure continues. In this video I show and tell about:
- 12 coils (12N)
- 14 magnets (14P)
- dLRK winding schema
- WYE and Delta termination schemas
More than a year after staring this damn project, I finally decided what goes where. And on top of that, short description how Dualcopters works (or at least should work).
Keeping above in mind, it will look like this:
What is still missing? Place to put battery in and electronics. Next update as soon as I will have any update 😉
Arduino LoRa is a great library that brings LoRa support (SX1276/SX1277/SX1278/SX1279) to Arduino world. I'm using it in my Crossbow LRS project (still not stable enough for flight, work in progress). Until now, the biggest problem with this library I've found is that examples suggests that heavy protocol processing inside interrupt callback is fine.
Unfortunately, it is not. It can lead to unexpected processing delays, create conflicts with other interrupts, bus clashes and other hard to debug things. This is why, the better way is to do packet reading (and processing) inside main loop and use read callback only to set a flag. Like this:
Only please remember to set all variables modified in ISR routine as
Today another video tutorial. It's just simpler to show how to make something on video than with text and images. So, without further ado: How to make Inverted Vee antenna for 5.8GHz FPV at home. All that is required is:
At the end we have small and light FPV antenna that just works. Sometimes it's just worth to make something by yourself, right?
Yestarday I wanted to make a first "real" range test of my DIY LRS system. "Real", because RX was supposed to be on a flying wing, but only as an passenger. Actual control was supposed to be happening via FrSky X8R. Crossbow RX was only to measure RSSI and check for failsafes.
It, well, did not ended up very well. Just watch the video.
I finally did it. It took me half a year and at least 10 tries, but I finally winded a motor and it did not burned. More than that, looks like it works pretty, pretty, nice.
Next step: measure KV of my creation!
So, you want to build your own RC radio system? Long range maybe? Cool, I want to do it too. Since I'm pretty deep in that topic now, I can give you a hint or two. For example, have you thought about a protocol your radio system will implement?
Or rather should I say: protocols? Why plural? If you want to do a RC link that talks with popular radios like FrSky Taranis on TX side and servos or flight controllers on the RX side, it will have to implement at least 2 different protocols. More likely 3. And if you will want to add telemetry downlink, 4 or even 5…
Idea for Crossbow, DIY LRS system did not appearned in my mind out of nowhere. All my previous LoRa attempts were aimed at telemetry purposes only. E45-TTL-100 are cool, but bulky. If I would want to use them, I would either have to attach Arduino to it or hack it open and reprogram onboard CPU (like Qczek LRS does). Somehow it was not something what suited me very much.
But then I came across Adafruit Feather LoRa32u4 RFM95. Awesome idea. ATmega32u4 and HopeRF RFM95 LoRa module on one PCB, Arduino compatible, reasonably small and light. As a bonus, can be LiPo battery operated and has own 1S LiPo chanrger. The only thing I did not liked (OK, not the only one, but that was the biggest one) was price tag: $34.95 is somehow slightly more than I'm willing to pay for ATmega32u4. Even with radio module. So, after some digging on eBay I've found something that looked like a clone of Adafruit Feather LoRa32u4 RFM95: BSFrance LoRa32u4 II.
Since I just started to add support for "old" FrSky XSRF3O flight controller to INAV (expect this in a release after 1.8) it might be a good idea to share few words about it.
First of all, it comes in a box. Why am I mentioning this? Because none of my flight controllers, and I own at least more than a dozen, came in box. C'mon, this is huge! I'm not joking, this is really a nice touch.
Looks like crappy range problem from previous post is fixed now. Today I managed to reach 2.8km range with better antennas. The ones I got from LoRa32u4 supplier were NOT 868MHz antennas for sure! 2.4GHz/5GHz probably, hard to tell. Traces on PCB are ~60mm long, so perhaps those are loaded 3/2 monopoles for 2.4GHz or 1.2GHz? No idea.
Anyhow, I soldered 78mm long copper wires to both TX and RX and did the same route as yesterday. At 500m link was solid. At 2.8km, link was solid when antenna polarizations were matched. With 40dB of link budget still to spare. Quite nice!
LoRa modulation was set to:
Now it's time to optimize air protocol a little and shave a byte or two…