Pi Zero Drone Post 7: Modular Body

Quadcopter Post 7: Modular Design

To the reader who has a smaller print bed and wishes to print this part I have designed a modular frame that will hold all the same components as before. Each print will not exceed a 114mm x 114 mm

I have attached the STL files with this post 

Here is a link to the STL Files:

Nano Blade QX2 Repairs

We have two of the Nano Blade QX2 drones at the Boca bearings workshop and I have to say they are a really great option for someone who wants to get into FPV flying/racing. Horizon Hobby sells them for $159.99 and they are sold as a BNF (Bind and Fly package). Only thing about them being bind and fly is that they have to be controlled by a Spectrum transmitter or any other transmitter that has DSMX or DSM2 protocol. However it seems to be mostly Spectrum radios that have it. And we have been using the Skyzone and Fat Shark Teleporter headsets to fly the drones.

We actually only had one of them at first though. But per usual we ran it into something and the drone broke. But that is part of flying drones. I wish I had a picture right after the crash but basically what happened was the camera case on the front of the drone broke and the camera split in half. We began looking around online and we really could not find anywhere that had the replacement parts.

Here are a few of the websites we found:

The only thing missing from the replacement parts list above was the camera and camera case. But we did manage to find that online too.

Camera Case:


But instead of ordering the camera case I figured it wouldn't be too much to draw something up in CAD to replace the case instead of ordering it. And I wanted to get more familiar with Onshape. Although I am more fluent in Solidworks from using it at school Onshape is a pretty awesome program because it is all cloud based. That means that you can pretty much use it on any computer you have as long as you have pretty good internet connection. I even have it on my phone, which totally blows my mind. Because you could have a $500 dollar laptop with a 2.0 Ghz processor 4GB of RAM and still be struggling to run Solidworks. And Onshape makes it pretty easy to collaborate with other people on the same project. Here are some screenshots of the parts I made in Onshape.

Now the real tricky part of repairing the cameras on these drones is that the wires connecting everything are super super tiny. And when I say that I mean 4 stands of braided wire tiny. Which means while you are soldering them you have to be real careful not to pull them out (which I did multiple times). Here are some pictures of the iron and microscope I used to solder it back together.
 Had to scrape the adhesive off to reveal the pad I was going to solder it to.

So after that was done I 3D printed the new camera holder out of ABS and decided to use acetone to "weld" the two pieces together. That is one of the cool parts of using ABS not only is it stronger than PLA but it dissolves in acetone so you can glue two pieces together by melting the two pieces a little bit and holding them together until the acetone dries which happens pretty fast. The bottle below has the acetone is it and I use the sponge on top to wipe it onto the plastic and melt it.

And here is a picture of both of the drones. Now that we have two of everything we will have to get some races going soon. Hopefully we can make that happen and I will have a video to upload.

Luke Ridley

Pi Zero Drone 6: After First Flight and Mods

Quadcopter Blog Post #6: After first flight and mods

After the failed test, instant modifications to the design must be made. The most importantly was to protect the hardware so that no more time and money is lost waiting for parts. I have added a 3-D printed ABS cover that will protect the PXFmini connections and also add some style to the quadcopter. The design of the cover can be seen in the picture below:


In addition to protecting the quadcopter brains, the controller of the quadcopter has not been as responsive. Some research lead to a possible solution, the APM software that I am connecting to via Wi-Fi was interfering with the signal of the RC controller. The theory is this the Wi-Fi of the PXFmini operates at its own frequency band and the same goes for the RC controller. If the PXFmini comes close to the same band the PXFmini signal will be distorted and must be changed. In the US, a certain frequency band must be used for operations set by the Federal Communication Commission (FCC). Without getting too much in depth, you must choose the channel bands if you are operating in 2.4 GHz (Channel 9) or 5 GHz (Channel 40). Check out the chart below:

CHARTS OF FREQUENCY BANDS (2.4GHz Bands & 5 GHz Bands image)  

To check if the PXFmini is operating in the right channel use this command:

Check the channel # in the following file:
Make sure that the channel # is 40.
Now check the signal strength using this command:

After it is changed, connect to APM and turn on the controller. The interference has now been fixed.

Pi Zero Drone: Test

Quad Post 5: Test

Check out the video to see how to arm the quadcopter.

Arming Video:  https://www.youtube.com/watch?v=9BmgpX3vKM0

Quad copter test 1….. FAIL

Crash Video: https://www.youtube.com/watch?v=GUAmSo_e-a0

Crash Picture

After this test the PXFmini GIPO pin connection sheared from the PCB board and became useless. But from the video evidence I suspect that the trim on the remote may have been to an extreme right and also a bad ESC calibration. I am waiting for a new PXFmini to come in and I will retry.

There have been some modifications of the design on the quad:

  • Shorter legs with Lipo Battery slot made from ABS plastic.
  • Roll cage that will save PXFmini from future crashes.

Fitbit Cheat-O-Matic 2: 3D Printed Mechanical Simplicity (9-8-16 update)

As a preview to what this thing is shaping up to be, here is the gear motor and the new cam design. That new cam is what the bearings will be riding on to make the fitness device move up and down to fake it out. :)

Inline image 1

The cam follower will snap through the inner hold in the bearing with something just like this:

Inline image 2

It may take a few prints to get the tolerances right, but that's the concept. In this version of the Cheat-O-Matic, the follower will have a light spring damping the vertical motion so it doesn't hop up and down as harshly as the one in the video on my site.

Still a lot of CAD to do. This thing has a toggle switch for power and a port for a 12V DC plug. Hopefully the prints will come out nice and within tolerance and I won't have too much nylon fiddling to do to get the prototype working.

Talk to ya later!


Fitbit Cheat-O-Matic 2: 3D Printed Mechanical Simplicity (Intro)

 I've been getting more into 3D printing, lately. One of the many things I felt could benefit from 3D printing technology was the Fitbit Cheat-O-Matic (version 1) I wrote about a while ago. It's very funny (as in, I built it as a joke; see previous linked article) and it even got some press at BBC.com. The crazy thing is I've gotten a number of emails from visitors to my site asking if I could build them one. They all were willing to pay for it, as well. That's cool. I don't judge. ;)

The first design was kinda simple and never really built to run indefinitely; on the contrary, it was meant to last long enough for the office Fitbit competition at the time (about a week I think). It was enough to get me through a competition, anyway. Certainly not a design I'd wish to build multiples of and then sell. They would have all failed soon after their users started them up. Turns out RC servos, even the high-quality all-metal-gear ones. I killed three different kinds of servos, one of them being VERY expensive.

I was watching old engineering videos from 1939 on YouTube one day and saw a cool demonstration of a cam and follower in a machine of unknown purpose. I realized then that I could make a very simple contraption using 3D printing and a geared DC motor to shake a Fitbit up and down very easily. It could be super-simple to assemble, cheap to print all the parts but the motor and probably run off a simple 12V wall wart power supply.

This is the CAD design of the new Fitbit Cheat-O-Matic, done in Onshape cloud-based CAD:

Fitbit Cheat-O-Matic 2 3D CAD Rendering in Onshape

The yellow piece is the cam. The dark grey piece with the cross thing on it is the follower and also the holder for the Fitbit. The light blue shaft sticking through the cam is the shaft from the geared down part of the 12V DC motor. The big round cylinder in the back is the motor. The lighter gray and dark blue stuff is the base. The dark blue piece is the part of the base the gear motor is attached to using two screws. The base fits onto the bottom of the faceplate with a simple tab and the two sets of side supports. Here is the exploded view of the CAD rendering:

Exploded view of Fitbit Cheat-O-Matic 2

I 3D printed the parts at Xometry (http://xometry.com). The tolerances on this first attempt were a little tight, so I'm changing up the CAD a bit to save me some plastic shaving and trimming. That's mostly because I'm still kinda new to 3D printing. The total cost for the four parts and shipping was about $50. If I got around to buying a 3D printer, that would be much cheaper, of course.

The 12V DC gear motor came from Robot Shop (http://www.robotshop.com) and cost about $25 with shipping. The gear motor is design to run at about 58 RPM. Since the cam has two high sides, it pops the Fitbit up and down about twice a second which is a pretty brisk walk, if not a run.

The screws I already had on hand. The power comes from a cheap 12V wall wart power adapter from Radio Shack. Anything that can provide about 60 mA of power will suffice. That's the draw I measured while it was running with a Fitbit attached. 1 amp adapters are pretty easy to find.

Here's the Fitbit Cheat-O-Matic 2 in action:

Originally, I'd designed a gap between the cam and the holder for a 1/8" steel ball, thinking that would allow smoother operation. Turns out that caused a tiny bit of binding which made the device louder and made the motor work harder. Without the bearing, the plastic-on-plastic is quite smooth and doesn't appear to be wearing at all.

As far as efficiency, as I write this it is 8:38 PM. The Fitbit app says the machine has racked up 116,000 steps since midnight. I think it's on its way to about 135,000 for a 24-hour period. I was told there'd be no math.

Screenshot from iPhone for Cheat-O-Matic stats for today

I will compete separately from the Fitbit Cheat-O-Matic 2 in future office competitions. I'm a healthy person with a healthy sense of humor, so don't go off on a "that guy's lazy" rant. I am lazy in that I prefer to find faster ways to do things, but I'm certainly not a slug or a lump. Let's keep that straight. ;)

I like making things even if they have no real useful purpose. THIS device certainly qualifies. If you're interested in purchasing one, drop me a message. I'll work on getting them up on my store on this site. Haven't worked out a price since everything has been purchased at one-off pricing.

Andy is using Boca Bearings and has agreed to allow us to present his latest project as part of our workshop. Andy's original post can be found here