The Foldy Quad - Custom Made Mini Quad Build Log

[x0054]

So I finally received my KISS ESCs and it's now time to start building my custom made mini quad daubed the Foldy Quad! To start with, I want to thank Twitchy for cutting out this quad for me. If it wasn't for him, I would probably still be hacking my way through G10. But with his CNC skills my digital creation became a physical one effortlessly!

Design Goals

I wanted to create a small, elegant, foldable mini quad, something that can be easily thrown into a bag. I also wanted it to be fast, capable of flying with a GoPro in it's case, and capable of using 6 inch props. While researching designs I decided that I want to stay away from the H-Quad design, because it's really popular now, and I wanted something new. Plus, the H-Quad design limits how compact the quad could be when folded, and it's also not the most aerodynamic design when in fast foreword flight.

While doing my research I was inspired by the Cyberquad, posted on this forum, and the Warpquad. I liked the traditional X layout, so that's what I designed around. But I gave it a twist The Foldy Quad was born on a hot High Desert evening in AutoCad:





The Build

I got my parts from Twitchy a few weeks ago. They were perfectly packaged and cut out. Really high class! Everything fit perfectly. There was a small discrepancy on the motor mount wholes, but I think that has to do with my design files. After this build I am going to make some modifications to the frame design, so it goes together a little easier. Incidentally, if you guys like the frame, I may market it. But I have to get it flying first So here are the parts:



The frame uses 8 screws and 8 standoffs. The top and the bottom plate are linked together, but isolated from the middle (dirty) plate. This means that a GoPro or an FPV pod can easily go directly on the top plate, and you don't have to worry about vibrations. The top and the bottom plate are connected so that the mass of the battery can dampen the vibrations. Here is a shot of the frame all assembled, with no motors.







Because I only have one FPV setup, and because sometimes I want to fly without FPV, just for some LOS fun, I designed the FOV gear to be fitted into an FPV Pod, that perfectly fits on top of the quad. I am going to use that new style all plastic Velcro to attach it:



The frame is designed to handle a 2.2Ah battery and 2204 motors. Here are a few shots with Cobra 2204 motors and 6x3 HQ Props on:





And here are a few shots of the frame folding and folded in my hands. I do have large hands, but for reference the frame, when folded, without the props, is roughly the size of a softball:





The Electronics

This will be short, as so far I only got the KISS ESCs mounted. They are designed to be mounted directly on the arm, very close to the motor. The arms with the brown signal wire are CCW spinning, and the once with yellow wire are CW. The KISS ESCs are really cool, they have a jumper (JP2) which when shorted, spins the motors in the CCW direction. So it's really easy to wire. Soldering to the ESCs is also really easy! Here are a few shots:









The End for Now

Well, that's all the time I have for tonight. I'll post more updates as I have news. I need to find some kind of easy to connect 6 wire connector, so I can easily plug and unplug the FC. I also need to pick up tomorrow some more battery connectors, and some plastic thumb screws. I am looking for some M3 plastic thumb screws to use as the lock screws for the arms. That way, in a crash, the plastic screws can snap, rather then the arms.

Let me know what you guys think

- Bogdan

 

[cranialrectosis]

Man that is beautiful.

Love those Cobra motors on the KISS ESCs.

 

[eagle4]

Dude that is awesome. I absolutely love compact folding designs. I love your clean and dirty design. But I wonder how that's going to go in a crash. I'm very excited to see how this goes once you have it in the air.

 

[Twitchity]

That quad is looking great, and its nice seeing it built. When I was cutting the pieces for the frame I wasn't sure what I was looking at. Now that I see it assembled, it is a nice design. Can't wait to hear how it performs and see some on board video.

 

[x0054]

Hi all,

So here is a little progress report. I had a few setbacks, but it's flying now! Thanks to FinalGlideAus for providing the base tune for me, because the default tune was way, way, off. But now it's flying good, just need to be further tuned. Unfortunately it's way too windy outside today to get any kind of tuning done, plus I need to wait for the new props to arrive.

The Setbacks

1. I used the Pololu 5V regulator to supply the 5V to the Naze and receiver. I also added a voltage splitter to the unit to feed the analog port on the D4R-II receiver, so I can have low main battery alarms. I was very proud of my little voltage regulator setup. Here are a few pictures:







It worked perfect! Unfortunately, during final assembly I accidentally reversed polarity when plugging the regulator in. Nothing happened, no smoke, nothing. But nothing turned on either. However, after properly connecting it, the regulator just would not work, and after keeping it plugged in for about 30 seconds it started smoking At least I didn't damage any of the other components. So I am using a very small little 3A 5V BEC for now instead. It's not nearly as tiny as the Pololu, but it's fine for now.

2. I thought I had a set of 4 6x3 HQ props. And I do, 3 CW and 1 CCW! Only discovered it when I was ready to go flying ad realized that both of my orange props are CW The only thing else I have at the moment is a set of 4 black 3 bladed 6x4 props and a set of black carbon fiber 5x3 props. The 5x3 are very underpowered on this quad. The 6x4x3s are ok, but I do not like them because the blades are very narrow and don't really push all that much air. But, the worst thing, all the props are black, so figuring out orientation when the quad is more then a few dozen feet away from me is impossible, and it's too early for FPV.

3. You may have seen my other post on this board about tuning Naze32 with KISS ESCs. FinalGlideAus was kind enough to give me a setup that worked. The stock PIDs were so much off that I thought something was seriously wrong. I guess I am just new to this. I built 3 multirotors so far, and they would always fly on the stock PIDs, not well, but would fly and I could tune them bit by bit to make them more locked in. But this one was just so crazy from the start that I immediately thought that something else was wrong. What it comes down to is that the KISS ESCs have an amazing response time, not just in how fast they can spin up the motors, but also in how fast they can stop the motors as well. This means you really have to dial back the P value to stop the crazy oscillation.

As soon as the winds die down to below 40-50MPH we currently having here, I am going to tune it to get it to respond a little quicker to pitch and roll, but it's not flying to bad as is currently.

The Build Continued

For my receiver I used the FrSky D4R-II. I like to remove all the unused header pins from these receivers and shorten the 3 remaining once. Here are a few shots:







I didn't have shrink wrap that would fit over the receiver properly, but I found this little trick that works well. You can stretch shrink tubing by 20-30% by using needle nose pliers like this:



It gives you a little more room to fit something inside the shrink tubing, and once you heat it with a heat gun, it shrinks right down, just like always.

I mounted both the receiver and the voltage regulator directly on the back of the Naze32 with some hot glue. Hot glue works perfect because it's really tough and holds well, but with a little isopropyl alcohol it falls right off.





It didn't come out as clean as I hoped for, but it's not too bad. I think if I was too hard wire everything, it would be a little cleaner, but I chose to keep it more modular. I soldered only the signal pins on the Naze32 outputs, to keep is as light as possible.

I din't get any shots unfortunately of the power distribution harness, so I'll have to make another post about that. It actually came together very quickly. Any way, here are a few shots of the final product on the scale with 5 inch props on. It looks a little odd, to me, because it's designed for 6 inch props. It's not too portly by it's self, but I do like to use those heavy 2200 mAh batteries, which pushes it just over 500g.





As soon as I have my new 4S battery and some 6x4.5 HQ props, I'll post some flight videos.

Also, if any one knows of a good place to buy some M3 plastic or aluminium thumb screws, please let me know. I need some for the folding mechanism, but all I can find is steel, which is much too heavy. Thanks!

 

[jhitesma]

2. I thought I had a set of 4 6x3 HQ props. And I do, 3 CW and 1 CCW! Only discovered it when I was ready to go flying ad realized that both of my orange props are CW The only thing else I have at the moment is a set of 4 black 3 bladed 6x4 props and a set of black carbon fiber 5x3 props. The 5x3 are very underpowered on this quad. The 6x4x3s are ok, but I do not like them because the blades are very narrow and don't really push all that much air. But, the worst thing, all the props are black, so figuring out orientation when the quad is more then a few dozen feet away from me is impossible, and it's too early for FPV.

Don't you hate that I have two bags of props that are fine...but none of them match up into a usable set. A few match up into single color sets I'll be able to use for FPV...but most are just prop styles I tried but didn't like and am just 1 prop short of a set...but have 3 of one corner

3. You may have seen my other post on this board about tuning Naze32 with KISS ESCs. FinalGlideAus was kind enough to give me a setup that worked. The stock PIDs were so much off that I thought something was seriously wrong. I guess I am just new to this. I built 3 multirotors so far, and they would always fly on the stock PIDs, not well, but would fly and I could tune them bit by bit to make them more locked in. But this one was just so crazy from the start that I immediately thought that something else was wrong. What it comes down to is that the KISS ESCs have an amazing response time, not just in how fast they can spin up the motors, but also in how fast they can stop the motors as well. This means you really have to dial back the P value to stop the crazy oscillation.

Been there. On my knuckle as I upgraded it I would go back to a stock tune and every time it would fly...but then fly a lot better once I tuned it. Then I made the jump to simonk ESC's - stock tune wasn't even close anymore and I thought for sure it had to be a problem with the ESC's. But tweaking the tune was the easiest thing to try and sure enough it was just that the ESC's were such a big step forward the stock tune wasn't going to cut it.

As soon as the winds die down to below 40-50MPH we currently having here, I am going to tune it to get it to respond a little quicker to pitch and roll, but it's not flying to bad as is currently.

You've got them over there too huh...sounds a little stronger than we've got here in town but I bet out at any of my flying spots it's just as bad or worse.

Also, if any one knows of a good place to buy some M3 plastic or aluminium thumb screws, please let me know. I need some for the folding mechanism, but all I can find is steel, which is much too heavy. Thanks!

I'm pretty sure I saw nylon thumb screws at either my local Ace or one of the bigger chains...just not sure if they were metric or not. I'll keep my eyes open though, I need to go look for a few nylon bits myself this weekend.

 

[x0054]

Don't you hate that I have two bags of props that are fine...but none of them match up into a usable set. A few match up into single color sets I'll be able to use for FPV...but most are just prop styles I tried but didn't like and am just 1 prop short of a set...but have 3 of one corner

I think the clear solution is to build a mini acro tricopter! I also have at least 4 sets of 3 matching props, perfect for a 200mm tricopter. Just need to figure out that pesky tail pivot mount. I am thinking about using helicopter ball joints as standoffs.

 

[x0054]

So as a really quick update, the quad has yet to really "spread its props" and fly all that much because the winds here have been crazy lately. It's impossible to really tune in these winds. Plus I have been trying to figure out how to connect a bluetooth module to it, so I can tune it on the fly.

I ordered 2 bluetooth modules form 2 different suppliers, one on eBay and one on Amazon. Neither worked. When I connected them to my laptop via FTDI, I was able to figure out that they both could receive data, but not send it out. Entering the AT command mode was a bust too, because none of the sellers could send me a data sheet for the module. Now I am waiting for a BLE module from Amazon. It's just a generic BLE to UART module, but I think I'll be able to make it work, assuming it works. At least I have a full data sheet for this one.

So the BLE module is arriving Tuesday and the new 6x4.5 HQ props and a 1.3Ah S4 battery are getting here monday Can't wait to take it out, hopefully the winds will die down by then.

- Bogdan

 

[Twitchity]

Mmm... mini tricopter that sounds like a lot of fun.

I'd gladly take the wind over all this rain we've been getting in FL any day, and news is saying there is a 60% chance of rain again today

I know you already ordered another bluetooth module, but if that one doesn't work check out the one from RotorGeeks http://rotorgeeks.com/index.php?route=product/product&path=34_44&product_id=165. According to the descrition is comes pre-configured and ready to work with the Naze. Shipping from them in CA to me in FL took 4 days too, so don't worry about it taking a long time for it to reach you.

 

[x0054]

Mmm... mini tricopter that sounds like a lot of fun.

I'd gladly take the wind over all this rain we've been getting in FL any day, and news is saying there is a 60% chance of rain again today

I know you already ordered another bluetooth module, but if that one doesn't work check out the one from RotorGeeks http://rotorgeeks.com/index.php?route=product/product&path=34_44&product_id=165. According to the descrition is comes pre-configured and ready to work with the Naze. Shipping from them in CA to me in FL took 4 days too, so don't worry about it taking a long time for it to reach you.

Better water poof your quad Twitchy You can give it a spray with that Neverwet stuff, and see how it work. I have seen people waterproof cellphones with that stuff, and I used it on PCBs before. But I am not sure how long it will last. I just did it for an experiment. Hope the weather clears up.

The wind has died down today and I took out the quad for a spin. I tried the auto tune on the Cleanflight, but the results were not at all like the results I got from auto tune on my Tri with APM 2.6. Instead of making the quad faster and more responsive, the auto tune made it very docile. Perfect for video work actually, but not at all fun to fly.

Instead I tuned it manually. Dropped the P all the way down to 1. Now it's very nice and quick. Even with the 3S it's now quicker then my skill set. Tomorrow I am getting a 4S battery in, and a set of 6x4.5 props. I think it's going to scream with those!

I didn't get video of it yet, because my current set of props is all black, so it's really hard to do anything crazy, because it's super easy right now to loose orientation. But next week I should have some flight video, and some FPV video from the quad. We shell see how my isolation platform worked out.

As for the BT module, I'll keep that in mind, thanks! That's the one I wanted to get, the HC-05 with 2 microchips on it. That's the real deal. I ordered 2 from 2 different vendors. They both had pictures of the HC-05 online, but what I got in the mail is some kind of knockoff with only on microchip on the board. For all I know, it could work perfect, but because it's a knockoff, no one knows how to get into the AT command mode to change the default settings on the thing.

But I want to try the HC-10, because it's BLE, which means it will work with iOS, so I can use my iPhone to change the settings.

I'll make a post about it if it works out.

 

[x0054]

I finally received my new props and battery yesterday, and got a chance to do some test flights with the GoPro. Here is how the Foldy Quad looks with the new pros and a GoPro:









It is very stable with the GoPro all the way on top, in the case. I am very surprised how stable it is actually. The vibration isolation cage worked brilliantly as well. I am still getting used to flying it, because from anything more than 100 feet away it's really hard to tell orientation. So the flying is so-so, please excuse.

This first video is of me doing some flips with the GoPro on top without the case. As you can see the props are in the view, which is a little annoying:

The second video is taken my the GoPro inside the case with the stand. It position the camera high enough to make the props drop out of view. It can still do flips and fly really fast!

Let me know what you guys think!

 

[jhitesma]

I love it. Like Cyber's quad and twitchitys new tri it has that ballish slightly top-heavy look that seems like it shouldn't fly well...but actually does

We've got to get you some FPV gear on there though - I have a hard time watching LOS flips filmed from on-board

 

[x0054]

That's a small flaw in my design. I can get my FPV pod onto of the quad, or the GoPro, but not both. I don't have a DVR for my FPV, so that's the only way I can make video. I need to add FPV transmitter to my GoPro, but that's not in the budget at the moment. I can actually hang the GoPro under the quad as well, but that makes landing a little difficult. I am going to give that a try tomorrow.

That being said, my FPV skills are still a little shaky. So even with the perfect setup, I will not be getting those cool flying through the trees shots, not that there are any trees around here.

I did get some quality time in today before the sun went down with my new battery, a 1300mAh 4S. I was very surprised to get 11 minutes out of it. I usually get 9-11 minutes on my 2200mAh 3S pack. I know the difference between those isn't as large as it sounds. The 4S is in actuality only about 27% less in capacity, based on it's watt hour capacity, but I was amazed to get identical flight times.

The quad is very fast with the 4S, much faster than my skills at the moment. Now I just need to practice that crazy 3D flying

As yet another setback, I am now 0 for 3 with BT modules. This time the module I got is just dead, as in just will not turn on at all. I rechecked that I have good 3.3V supply, made sure that I connected everything right.

 

[jhitesma]

As yet another setback, I am now 0 for 3 with BT modules. This time the module I got is just dead, as in just will not turn on at all. I rechecked that I have good 3.3V supply, made sure that I connected everything right.

Did you, like, desecrate some kind of bluetooth holy site or something

That's crazy that you're 0 for 3 on them. I'm still racking my brain trying to think of something you haven't tried with the first two.

 

[Craftydan]

I've had issues with them from some of the EBay vendors . . . really frustrating to troubleshoot when EVERYONE says "it just works" and it doesn't.

From what I've seen, it was poor soldering between the two boards that left various connections cold. One had a cold joint such that when you squeezed one side of the board it would work . . . otherwise it wouldn't. On another, only the TX channel would work -- made a loop back with an FTDI adaptor and a bluetooth module -- connected both to separate hyperteminals and . . . huh, whadja know, it only talks one way

My current one seems to be solid, and I gather the more reliable the vendor, the more likely it will work consistently . . . but what's new about that?

 

[jhitesma]

Yeah, his first two both did the same one way thing when setup in a loopback test. I believe they're both the "neweer" brand but from different sellers (one from an e-bay seller I've had great luck with and I think his other was from Amazon.)

The one I have was from HK and worked perfectly for awhile - but after a good number of crashes the connector has gotten a bit flaky. I keep meaning to remove it and just solder the wires right to the board but as usually it starts working fine every time I think about doing that and only acts up when I don't have a soldering iron handy

 

[Craftydan]

Well then, perhaps a cheap threat to keep it in line?

 

[Twitchity]

That little quad takes fairly nice video, I'm impressed. It looks like that quad would be extremely hard to fly with that GoPro sticking up so high.

 

[x0054]

That little quad takes fairly nice video, I'm impressed. It looks like that quad would be extremely hard to fly with that GoPro sticking up so high.

It's actually remarkably easy to fly! The battery on the bottom nicely counterbalances the top camera. But when I was doing my first flip with the camera on my hart was pounding. I was concerned that it will flip upside down, but then not have enough power and leverage to right it's self up again, and just plow head first into the ground. Amazingly, it flips, rolls, and corkscrews with ease! I am very surprised my self.

 

[x0054]

I've had issues with them from some of the EBay vendors . . . really frustrating to troubleshoot when EVERYONE says "it just works" and it doesn't.

From what I've seen, it was poor soldering between the two boards that left various connections cold. One had a cold joint such that when you squeezed one side of the board it would work . . . otherwise it wouldn't. On another, only the TX channel would work -- made a loop back with an FTDI adaptor and a bluetooth module -- connected both to separate hyperteminals and . . . huh, whadja know, it only talks one way

My current one seems to be solid, and I gather the more reliable the vendor, the more likely it will work consistently . . . but what's new about that?

As Jhitesma mentioned, that's exactly what I had, only in reverse, RX only. I traced both RX and TX connections all the way down to the pins on the BT chip. But who knows what else might be wrong with the BT Chip it's self.

The last one was just hilarious though. I was all prepared with a datasheet opened on my laptop, FTDI connector setup, and everything. Soldered 3.3V and Ground pins and connected it up, and.... nothing! At first I thought maybe I reversed the power or connected it wrong. But after 10 minutes checking and rechecking the 2 wires I connected, and verifying that system LED does not light up, I gave up. I google to see if there was a trick to get the HM-10 BLE module booted. There isn't, it's just power and ground on pins 12 and 13. But apparently, quite a few people got dead HM-10 modules, and had to return them. When they work, they work, and when they do not, they just do not.

The last module I got was reflow soldered brake out board, just the top board for those common modules. But checking it under the scope, I did notice that the pins for the main chip were quite deformed on one side. They looked like they still made all the right connections, but there could easily be a pin to pin short I have missed.

Back to Amazon it goes. At least it's easy to return things with them.