Tag: drones

Up in the Air – Returning to building and flying racing drones

Over the last year or two I’ve taken time off building and flying quadcopters. Life and other things has been taking up my brain, so some hobbies took a back seat.

Up at the lab, an event was coming up that would bring in some other pilots from New Hampshire and do a race day. I decided it was time to build a new quad, and get some race time in.

The last big event I went to was NAFPV 2017. It was great fun, and I ended up winning a 220mm carbon fiber frame. With that in hand, I began building up a new quad.

The technology has changed dramatically since my first builds. All in one components, ‘stacks’, and other tech has made the builds both more complicated (lots of tiny wire soldering), and easier (most boards are the same size, and can be stacked on top of one another). Turns out pretty much none of the components I had on hand would work on the new quad, so I had to purchase all new pieces. Here’s what I ended up with:

  • Wolfwhoop TX1912 5.8 video transmitter – I chose this board for the MMCX small antenna connection, and the ability to select bands and channels easily via a button and an LED display on the top. Super handy.
  • CaddX FPV Camera
  • CrazyPony 4in1 ESC This is probably the biggest change for me. Originally I built quads using separate discrete ESC’s. This board puts all 4 ESC’s on a single board. It definitely makes the wiring cleaner, but a little denser on the stack.
  • Crazypony 2206 2700kv motors
  • Betaflight F4 flight controller Betaflight is certainly the star as far as flight controllers and software goes right now. Their configuration tool is excellent, and the board is very good. I was slightly concerened about working with a board that had no header pins, but decided to roll up my sleeves and get experience in very tight soldering setups.
  • FS-X6B Flysky receiver – Yeah, I’m still rocking the FlySky setup. It’s still working well for me. I like this receiver because it can mount on the component stack (even though it’s a half-board).

Quadzilla
The build went off without too much trouble. I found all the missing tiny bits I needed, did lots of very small soldering, and over the space of 3 weeks, got everything assembled and tested. It worked! All the components were talking to each other properly, and I even have a fully function OSD (on screen display) showing stats from the batteries, flight controller, and receiver. Even got the LED strip showing the arming state and a set of ‘tail lights’. Hurray!

I did a very quick flight test to check stability, then went up to the lab to put the final touches on things. This is where I made my first mistake.

Kids, don’t do this.
I decided to take Quadzilla outside for a quick LOS test fly. My FPV gear wasn’t ready for flight testing, but I wanted to see the LED’s and play around. I put the quad on the ground, armed it (which spin the props slowly), stepped back, and gave it a little throttle. The quad lifted, started to move backwards, and basically… fell into my hands… still throttled and running. Those props HURT. I scraped up my hands a bit before I was able to disarm.

So what did I do wrong? Pretty easy actually.

  • I flew Line of Sight at night. LOS requires visibility on the yaw, pitch, and roll of your craft. I coudln’t see it, it was too dark.
  • The rear LEDs were pointing at me, which made it even harder to see.
  • I was in Air mode, not Angle mode, which means there was no flight stabilization. Quad did what I told it to, which in this case was to fly right at me.

Embarrassing, slightly painful, but no major harm done. Bleeding stopped within 10 minutes.

Chagrined, I took the quad home, cleaned up, and started prepping for the race, which would be in 3 days. The quad was pretty much ready to fly, I needed to set the mode selector properly, and tweak the LEDs. I also decided to move the battery from underneath the frame to on top of the top deck. Plenty of room there, and the quad would sit on the ground when taking off or landing, not on the battery. Win!

Turns out my batteries needed some love. The 1300mah 90C batteries i got last summer had been sitting idle for a year. Of the 8 batteries I had, one melted while charging, another was puffy so I decided not to use it. That left 6, which charged okay, but my parallel charger has seen better days. A new gang charging situation is needed, more on this in another post.

I charged all my other gear, including a nifty little all in one 9″ monitor with build in 5.8 receiver I carry with me. Great for checking video and watching other pilots fly. I packed up everything into the Jeep and on Sunday, headed up to the lab for race day.

The folks from the 603 Southern New Hampshire Drone Pilots group showed up, bringing our total pilots to about 10. We ran a couple heats with 4-5 craft in the air at once, on a short ‘H’ shaped course that had several gates and a ‘turnaround’ cube in the middle. The course was off the end of the back parking lot, so there was plenty of room to drive up, park, set up your tables, and get flying without fear of getting hit or getting in anyone’s way.

I flew 3 batteries. First flight was a very basic FPV test (as really this was my first FPV time on the new quad this year, and things went fine. Video was strong and clear, and the quad was very responsive. I flew completely in Angle mode, which is a VERY simple flight mode. I wasn’t comfortable enough yet to go into anything that would let me go more crazy. This was a first time out, I didn’t want to shatter anything.

Second battery apparently was in bad shape. No strong thrust, just running limp. I figured out later the 4S pack had a dead cell, and was functioning as a 3S. That explains that.

Last battery was in good shape, and I was feeling the power of that 4S setup. Unfrotunately, because I was in angle mode, I couldn’t pitch forward enough to get decent speed out of it (I’d just climb), so I was taking it pretty easy. I flew a gate or two, then went through the last one on the course – I caught a motor on that, which spun me out into the trees. The damage to Quadzilla is pretty minor, but I did rip out my VTX antenna, so that ended me for the day. I’m not complaining, I flew, I had a great time with the other pilots, and you’ll be damned sure to see me flying again soon.

Charging Multiple Lithium-Polymer (Lipo) Batteries at once

As any quadcopter / drone pilot knows, the more batteries you have on hand, the longer you can stay out doing what you love – flying! Unfortunately, this comes at a price, and no I don’t mean the cost of the batteries. Those puppies need to be recharged before you can get up in the air again.

When the sport started, many people had single chargers – a single power source that could charge one battery at a time. That didn’t last long, and gang / parallel chargers became the norm for active pilots.

But charging batteries in this way needs a little math. And since I spent this morning doing it the WRONG way, lets quickly go over the RIGHT way to do this.

The components

First, lets review the pieces.

  • A power supply. The juice has to come from somewhere. I’m working with 3S batteries, which run at 12v so my PS needs to match that. Tenergy sold a very nice little power supply with the charge controller I use. The most important thing to note on the PS is it’s rating. Mine is 5000ma (5 amps). I can’t draw more current than that. Remember this later.
  • A Balancing Charger. I use a Tenergy TP6-B charger, which has served me super-well.
  • A balance charging board. There’s zillions of these out there, ranging in quality all over the map. They’re pretty simple devices. Looks like Crazepony has a decent one that includes fuses. I picked up a cheap chinese version a year or two ago.
  • Batteries (duh). What sort of batteries you use is completely up to you. When doing gang charging, they have to be the same voltage (2s, 3s, 4s, whatever), and relatively close in their C ratings and capacity. In this article I’m using Floureon 1500mAh 35C batteries, which are pretty low-end in the current world (new 4S batteries are on the way!)
  • A charging bag. This is for your own safety and the safety of your house, but it’s a good idea no matter how you slice it. I use a bag most of the time, though the photos below do not show it.

Great, but, what amps to use?

And thus the question is asked. When using a balancing charger like the Tenergy, there’s several menu options for how many amps to charge with. The general rule of thumb is you should charge your LiPo batteries at ‘1C’, meaning putting the amps into the battery that matches it’s capacity. For my batteries, they have a capacity of 1500mah, so I should charge them at 1.5A. Easy, huh?

Balance Charger

Now we start talking about parallel charging, where you’re charging more than one battery at a time. They are hooked up in parallel (so in essence look like one big battery to the charger), so when calculating what amperage to use, just add up all the capacities.

BUT! (there’s always a but, huh?) – whatever power supply you’re using can only provide so much current. Look on the power supply and you’ll see something like “Maximum 12v 5000mah” (or might just say ‘5A’). That’s the maximum current the power supply can crank out. You should never set up your charger to draw more than that value. It may work, but you’ll be stressing your power supply and could over heat / damage it.

So, given all this, with my power supply rated at 5000mah, and I’m working with 1500mah batteries, I can charge 3 batteries at a time. I set the charger to provide 4.5A power at 12v, plug my batteries (and the balance plugs) into the board, and hit go!

So what did I screw up?

Well, somewhere along the line, I had forgotten the basic math above, and have been charging only 2 batteries at 1.5A. Which, as you can imagine, takes something like an hour and a half per charge. Somehow I got the cobwebs out of my brain and remembered the math, and just recharged 3 1500mah batteries in 45 minutes.

MUUUCH better.

Off to NAFPV 2015!

For the next 4 days I’ll be in Stephentown, New York at the North American FPV Meet flyin, racin, and campin. For the most part I’ll be livetweeting on the USDRA Drone Racing twitter feed (please follow!) which will also be posting to the USDRA facebook page (please like!).

This’ll be an interesting test of going camping using Soylent as my primary food source also. The campsite where the event is has no running water and no food services, so I’m bringing a cooler, 2 days worth of premixed Soylent, plus a few snacks. We’ll see how this goes. 🙂

Second article on Drone Racing.

The Globe was out again for last Saturday’s race, and did another article on us, complete with video.

You hear it before you see it: a high-pitched whirring that sounds like a dive bomber crossed with the world’s largest bumblebee. This past Saturday, the buzz came from the edge of a large field in Berlin, just miles from where Interstate 495 meets Interstate 290 outside of Worcester. Moments­ later, there was a loud thwack, followed a sympathetic “ooh!” from a dozen spectators.

Full article here: Drone Racing Takes Off

So, I made it into the Boston Globe.

Well, their ‘Innovation and Tech’ buzz site at least. But, cool, huh?

Dave Shevett is chairman of the US Drone Racing Association, an unaffiliated group based in New England. One day, he stumbled across an FPV drone-racing video online and was hooked. Not long after, he formed the USDRA. The group is small, but has been working with clubs in the Northeast to help set guidelines.

“When I got started in this hobby/sport/whatever you want to call it, no one had really tried to organize basic classifications and rules for running a race,” he said in an e-mail. “I decided to set up the organization to act as a sort of clearinghouse reference point for clubs.”

The latest tech sport taking the country by storm? Drone Racing.