Derek's ZMR250 Build

[Derek]

My package arrived yesterday, as anticipated. Very cool! I opened the slightly damage box and found all the parts and pieces to be present and seemingly undamaged. I was going to begin the build but I think I'm going to wait a bit until I get all the other components that I want. I need to get another vtx and FPV camera. I was also thinking about using a PDB board on this build instead of the usual mess of soldered and shrink wrapped wires. I was thinking about using a simple PDB board like this:

http://www.buddyrc.com/dal-rc-multiroto ... -2338.html

but then I found this:

http://www.buddyrc.com/zmr-250-power-di ... dules.html

I also need that antenna extension for the video antenna and probably a bit of spare wire.

I've been looking at some Google'd pics of other ZMR250 builds for ideas. There are some really good looking ZMR's out there!!

[Stambo]

I think I would go for the small one Derek, that should be stackable with the Naze32.
I think the other one requires replacing one of the frame members.

[Derek]

What do you mean "replacing one of the frame members"?

[Graham Lawrie]

You use the pdb instead of the lower frame.

[Derek]

You use the pdb instead of the lower frame.

Ok, that's what I thought he meant, but for some reason I was also thinking that he was talking about replacing something else. So, the ZMR PDB takes the place of the lower frame plate. Understood. I've decided to not order the ZMR PDB and just use a smaller PDB board that I can set below the Naze32 board. The new PDB board, and a few other accessories have been ordered. Probably won't make it here until Monday.

[Derek]

Ok, so my HK order should be here today...I think. I've just placed an order for a new ImmersionRC 5.8ghz vtx, new FPV cam, a VAS 3 turn helical LHCP antenna, and a VAS Dura-Spec antenna. I almost imagine that those parts will be here Thursday/Friday. As long as my HK order gets here today, I will begin the build. This is gonna be fun!!!

[Derek]

I remember seeing a few build videos where some people are using a 3D printed spacer between the bottom two plates on the ZMR. This spacer allows them to have a Bluetooth module and small OSD located in this space. Something similar to this:

Unispacer.jpg (39.07 KiB) Viewed 5251 times

Do any of you know if something like this can be purchased? Or would this just be a waste on my quad?

***EDIT***

Found it!

http://great3d.com/the-original-uni-spa ... -included/

[Stambo]

Anything that adds weight reduces flight time.

[Derek]

Anything that adds weight reduces flight time.

Yes, you're right. Maybe it's just better that I let this go. I planned on putting the esc's on the arms anyway...perhaps I can just tuck the Bluetooth module and minim OSD inside the frame somewhere.

[Derek]

And wouldn't ya just know it, lol. I had anticipated my HK order to show up today via USPS. Nope....because I had a single 4S lipo in my order, my package was shipped via FedEx. I checked the FedEx tracking site and it's saying that my order should be here tomorrow. I guess one day later than anticipated is all good but I really anticipated it to show up today, lol. So...i'll be bummed today and happy tomorrow, lol.

[Derek]

I've got the new ZMR250 built and everything is installed. I began to work on the Naze32 programming and setup. There is only 1 thing that I'm struggling with right now, because I've not done it this way before. Instead of using an actual Spektrum rx, I'm using just the Spektrum satellite rx. I have the red wire soldered to the 3v pad on the Naze and the black wire is connected to Pin 1 on the side of the board where the breakout cable would go. The signal wire is connected to Pin 6. I connected the ground and signal wires to those pins because thats where I saw others were connecting them in the Youtube videos that I saw. I hope this is right. If not, please correct me.

I went into Cleanflight and tried to set it up for SerialRX but I've not been successful. Can you guys help me here? How do I get Cleanflight to recognize the Spektrum satellite rx? And, if there are any other lil tidbits that I should be aware of.

I found a link to a github.com page that talked about SerialRX. It said to type "feature SERIALRX" in the CLI. I did that and it said "invalid command" or something like that.

I'm open to any thoughts, suggestions, etc. Thanks guys! I'm super stoked about getting back to FPV quads. Hopefully I can get this thing sorted tonight so that I can fly it tomorrow. The forecast for tomorrow is suppose to be near 80 degrees F with calm winds and sunny skies. Awesome!

[Derek]

Ok, disregard the above post, lol. Now I'm just pissed. I fixed the problem. In the Configurator, it now shows SerialRX and, in the Receiver Tab, I have full control of all 8 channels and they are all going in the right direction. So...I'm sure you are asking "If you resolved the problem, why are you pissed?" LOL...i'm pissed because I don't know what I did to get it to work properly, lmao. I clicked on this and checked on that, clicked here, clicked there, saved here and saved there...and now it's working. Ok...I'm not really pissed. I'm happy it's working...I just wish I knew what it was that I did to get it to work....ya know, lol.

Now...beyond that....I've got everything in Cleanflight set up like I want it. I'm happy that I was able to do that on my own. The only problem is....all 4 motors are spinning in the wrong directions, lol. I had a 50/50 chance of soldering the motors to the esc's in such a way that the direction would be proper and I got each of them backwards, lol. So, let me ask this question, I seem to remember someone saying that I can reverse the motor direction in the BLHeli software (my esc's are 20amp Afro's, flashed with BLHeli). Is this possible or am I confused? I'm just trying to avoid unsoldering the wires because I have the esc's shrink wrapped and they are very pretty. I don't want to have to cut into them, unsolder the wires, and then recover them. If I have to do that, I surely will. But I just seem to remember someone saying that I can use the BLHeli software to reverse the motor direction.

[Derek]

I spoke with a couple of racers in the Mini Quad Club, on Facebook. They gave me a link to a YouTube video that shows how to set the esc's through Cleanflight. I didn't understand much of what the guy was saying so I'm just gonna unsolder two motor wires on each esc and switch them. Simple enough.

Stambo, if you come across this...a while ago, you gave me two CLI commands that you said you always use. The commands were: set looptime = 2500 and set acc_lpf_factor = 100

I was able to get the looptime set but when I copied and pasted the other command, Cleanflight said "invalid command". Did I do something wrong?

I found a list of CLI commands here: https://github.com/multiwii/baseflight/ ... -Variables

However, I didn't see any command that was even close to that last CLI command that you gave me. Any thoughts?

[Derek]

Here's the finished ZMR 250 FPV quad

Finished ZMR.jpg (91.73 KiB) Viewed 5221 times

This was a relatively easy quad to build. I had ordered a PDB board. Unfortunately, it was very much the wrong size..much too big, so I just soldered up a simple wiring harness. I got the Naze32 all set up on my own this time. I need to find my Bluetooth Module and get that installed. Besides that, I have 4 brand new Sunnysky 2207-2100kv motors, 20amp Afro esc's flashed with blheli, 6x4 HQ props, brand new Mobius cam, VAS Dura-Spec 5.8ghz LHCP antenna on board and I have a VAS 3 turn helical 5.8ghz LHCP antenna for the ground station. I have some 3S 1550mah 35C flight packs and I have a brand new Multistar 4S 1400mah 60C pack.

I'm super stoked about flying the FPV quads again!

[Stambo]

Derek, that thing will be fast, real fast.
I have the same motors and batteries but I am running 5045 bullnose props.
I will soon look at 5040 3 blade props but the 5045 bullnose will do until I break a few more.
Your 6" props should give you more top speed at the expense of a little less acceleration but the power you have on 4s will still be insane on that setup compared to what you had.
Just remember the tune could be quite different between 3s and 4s.

Those CLI commands are pretty much outdated now, you can set all that stuff in the GUI.
I am running Betaflight now and it is working really well for me.
I guess I need to upload some videos from some of my latest flights.
I have actually been getting some hang time inverted like some of the pros do.
And multiple rotations during flips, my best is 3 so far but I am sure I can do more.

[Derek]

I plan on sticking with 3S packs for now. Not real sure why I ordered the 4S pack right now, other than HK had them on sale. I'll stick with my 3S packs while I'm tuning and getting acquainted with my new machine.

As for the commands being outdated....that figures. I'm always behind the times, lol. I'd like to see some of your latest flight videos, so get them posted, lol. I do enjoy seeing the pro's flipping and flopping and getting that inverted hang time....just awesome!

Instead of messing with the blheli software and potentially messing things up, I just unsoldered two motor wires from the esc's and switched them. It took me a whole 20 minutes to uncover the solder joints, unsolder the wires, switch and resolder the wire to the esc's, and then recover the esc's and solder joints. Now, all 4 motors should be turning the proper directions.

....now....where did I put those props? lol

[Derek]

Curious question.

I have a Bluetooth module and I have a MinimOSD (thanks Clay). Used individually, these would connect to the RX/TX pins that are soldered near the middle of the Naze32. Can I use both the Bluetooth and MinimOSD on my quad or would that add too much confusion to the quad's system? I'd like to have the Bluetooth so that I can use my tablet for making changes and I'd like to have the OSD for voltage display and flight timer.

[Derek]

After getting the motors all turning the right direction and checking that the quad balances in the center of the location of the Naze32 (with FPV gear and battery onboard), I took the ZMR250 out to the backyard for it's first test flight. In Acro mode, the quad nearly hovers hands free. I was giving very very little stick inputs to keep it in place...I blame the slight winds that were swirling around in my area. This thing is solid! I gave a hard throttle punch out for about a full second and the quad yawed to the right pretty hard. What do I need to adjust to compensate for that yaw on a punchout?

Once I get this yaw issue sorted, I believe this sucker is ready for some FPV circuits...YAY!!!

[Stambo]

That yaw is often caused by vibrations Derek.
Have you got some 5" props you can try?

[Derek]

Yes, I do still have some 5x4 props. I can surely try those and see what happens.

vibes suck! lol