I have been acquiring parts to build a development drone with the goal to learn integrating a platform to bring in quality aerial video, a companion computer such as a Raspberry Pi. So far I have the X500 ARF Kit, a Tarot GOPRO 3DIII for the GoPro Hero3/4, a GoPro Hero4 Silver. My choices for flight controller are a Holybro Pixhawk 4 Mini or a Mateksys H7A3-WING. I have both of these FC on the shelf. I have a Radiomaster TX16S Hall TX and an OrangeRX receiver. I still need to decide on the correct companion computer. There are some very powerful mico computers out there. but they but the tradeoff is power consumption. I need to understand how much companion computer computational power is needed and which FC to use. Right now I’m leaning to the Mateksys. The companion computer is wide open. This will have a 900mHz MavLink to a Linux based Ground Station. Any comments would be helpful.
I need advice with theses decisions. My main goal is integration and learn Ardupilot, Python and Mission Planner. This would be applied to the next build.
X500 is a good frame. The motors and ESCs that come with ARF are okay. They’ll get the job done.
For a flight controller, get a Matek H743, not the 7a3. Or a TBS H7 Wing. If you’re goal is coding then something with an H7 processor will give you more options and power down the road for on-board lua scripting and better i/o.
For radio, the TX16S is a good choice, but go with ELRS over DSM. If your TX16S has the 4-in-1 then just get a module, and I would suggest the Radiomaster Nomad module with an XR4 receiver. On ELRS 4 this will give you the ability to run Mavlink over ELRS and you won’t need additional telemetry radios.
I would 2nd the TBS H7 boards. I have been really impressed with them. I have a lot of Matek boards and like them but the H7A3 was a cost reduction product. Put the Pixhawk 4 Mini in a Rover…
Thanks for the tips. I will be staying with MATEK H7A3 for now. On your advice I did look at the H743 and it looks newer/better, but I already own the 7A3. Same goes for the DSM, at least for now. ELRS is in the future and on my list of things to explore. I saw this post and it has me a little spooked over the ELRS 4.0 protocol: Holybro X500 Crash . The ELRS team is working on it and have a 4.0.1 release planned. Use case for this drone is learning systems integration and I have ideas to go into precision GPS mapping for construction and aerial photography. THX JimP
I understand using what you already have, but I also wanted to say that despite the issues I had in that post I can definitely speak positively of the ELRS project/control link in general. I’ve used it for a least a couple years now consistently on multiple aircraft/aircraft types and not had any issues until this most recent one, for what it’s worth. Good luck on your learning project - there’s lots to be explored.
I just looked at that ELRS thread again and the PR with the fix suggests that it is tied to the 1280 chips, and switch arming. The hardware I recommended uses the LR1121 chips, and if your still worried you can use rudder-arming. Either way, it’s still worth looking at over DSM.
Getting the system running and operational would be a great achievement. Flying would be another achievement. I retired from Boeing after 43 years with the 14 years as an engineering manager in flight test (787, 747-8, MAX and 777X) Unfortunately, like most of us I operate on a budget. I’m trying to be progressive and deliberate about the copter. The DSM should be good to get the system running and ground testing. There is a heck of a lot of system work ahead. I get it about the ELRS and I know it will be worked out. I can’t remember if there were two or three crashes in your post. But it takes me back to what we went through in the MAX crashes. Thanks for the work you do with your students and sharing your experiences. JimP
Switch arming makes the issue worse (guaranteed unrecoverable drop), but unless we take our time before we consider throttle to be zero it still can cause disarm in manual throttle modes (failsafe at zero throttle disarm).
Alister, I went through the Radiomaster Nomad Dual 1-watt Gemini Xrossband ExpressLRS Module and DBR4 Dual Band Xross Gemini ExpressLRS Receiver. Also read the MAVLing page on eLRS. I would ne foolish to not use this protocol. The price is great and the performance superior. I need to find as US supplier. The only thing that is a question is the battery to power the Xrossband module. I’m thinking a 1P3S Li-ion battery. I’m not sure about the sizing or where it goes on the radio. THX for your comments on this one.
The Nomad just plugs into the back of the TX16S. In the “JR” Bay. It will power the module through the pins already in the radio. You would only need to worry about external power to the nomad if you’re running at 1 watt for extended periods of time. Since I run mine with MavLink and the receivers (XR4 and DBR4) are limited to 100mw of power output I limit my Nomad to the same. Even at that lower power the range is far enough to get you into trouble in most countries.
Agree the H7A3 will be a challenge. It is older, Ardupilot has dropped support. I’m looking at limitations of the Pixhawk4 Mini. To get reliable modern performance the ESC and FC should be of the same generation.
TY, Totally makes sense. The Nomad manual does not talk about this. MyTX16s is mainly used for R/C flying. A normal flying session barely puts a dent into the 3000mAhr 1P2S Li-ion. I’m guessing the radio’s internal would need to be balanced to an external battery.
With your help I have come to a better understanding. To do the things I want, I need a newer FC and radio. So today I pulled the trigger on a Holybro Pixhawk 6x and the Radiomaster Ranger module and the matching DBR4 receiver.
The goals are to get the quad setup and flying with the gimbal and go pro. Then integrate a companion computer such as the Raspberry Pi 5. Adding the Pi I should be able to get Video through Mavlink, Optical Flow, and possibly obstacle avoidance.Lots to learn.
I’m just sitting here looking at my workbench. I have the Holybro x500 V2, the Radiomaster Nomad, eLRS Dual band Gemini receiver, and a Holybro 6x flight controller. So I’m ready to start putting this together. For video I have the Tarot R/C gimbal and an old GP Hero 4 Silver. Video download will be analog, at least for now.
The only thing I’m stumped on is the antenna setup and mounting. When I bought DBR2 I didn’t get any extra antennas. so I’m a little stumped . The Y antennas that came with with the receiver make sense. It looks like they need to positioned in a vertical orientation along with the 2.4Ghz antennas.
Anyone have ideas on antenna mounts and how they should be position on this drone?
Do you mean DBR4? It has two 900/868 antennas and two 2.4ghz. On mine I choose to run it on 900/868. So I made mounts to put one antenna vertical and the other horizontal. Basically you can put them anywhere but keep a few things in mind:
Don’t put them inside the carbon tubes.
These radios are awesome, so if you’re only flying less than 1km you can probably do almost anything and they’ll work. Aka: don’t over think it.
Ideally you have the two antennas mounted 90 degrees from one another, and at the same relative 90 degree angles as the antennas on your Nomad module.
Since I”m not using the 2.4, I just tucked them away. Wasn’t sure if I could remove them but since this was one of the first dual band receivers i got I figured I’d leave them installed since I was playing with all the settings or I might have wanted to play with 2.4 at some point.
Allister, thank you for the tips. Your correct it is a DBR4. The receiver came with the wire antennas. We use 915 Mhz here in the US. I was a little confused by the Y antenna. The signal propagation is perpendicular to the antenna element. But the Radiomaster Y ant seems unique. The element is at one end and the other end is shielded. I’d like to understand that but I won’t get stuck in analysis paralysis.
