FAA Drone Questionnaire

I got an email from the FAA asking me to participate in a questionnaire about recreational drone use and information the FAA can provide.

One of the questions was How long do you typically fly? My answer was 60 minutes.  I usually have three fully charged batteries, each of which will fly for approximately 28 minutes. I like to land and swap batteries with a few minutes to spare, giving me a total flight time per session of close to an hour.

The form doesn’t like any answer more than 30 minutes. One more example of how out of touch the FAA is with the rapidly advancing technology.

DJI Phantom and Wind

This week I took my drone to video Initial Point in Idaho. It’s a rocky outcrop about 20 miles south of Boise that was chosen as the initial survey point for the Idaho Territory in 1867. It has a concrete platform installed at the top with a survey marker embedded. There’s a rocky trail that can be driven to the top if your vehicle has a high ground clearance. I chose to walk to the top.

Initial Point Idaho

My car was parked at the base, I climbed up about 130 feet to the top. The wind was occasionally gusting at the base. It was constant at the top, with much higher gusts.

I carried the drone in my backpack to the top, and launched it from the platform. I manually flew it around the point, but was feeling extremely nervous doing so. I only flew about 36 feet above the platform during the entire flight.

The concrete platform has a metal railing surrounding it, and I didn’t trust the drone to return safely to land without hitting the railing so I manually had it land nearby. As I was hovering the drone before landing, it was holding a fairly constant 20° lean because of the wind.

After hiking back to my car I still had plenty of battery for another flight. From near my car I launched the drone and flew vertically to about 200 feet, centered the drone over the survey marker, and used the point of interest feature to create a video circling the point.

I don’t believe that the wind was any less on my second flight than it was on my first flight. The fact that I was in the wind on the first flight had me feeling significantly more nervous while flying than when I was out of the wind on the second flight. Watching the video from the first and second flight doesn’t appear significantly different. I would have liked the point of interest video slightly more if I’d been on top of the point the entire time, but I was too nervous to do it all while I was sitting in the wind myself.

DJI Battery Monitoring

DJI charges a significant amount of money for their batteries and calls them Smart Batteries. I’ve seen the statistics reported of how many times the battery has been power cycled, as well as details of how much flight time is available. This was a new and interesting feature to me.

I had left the drone in the back of my car overnight. The temperature had probably gotten into the high 30s, and was still in the mid 50s with the sun shining. The warning message “Battery Temperature Too Low. Warm battery to at least 15 degrees Celcius before flying” came up on my screen and would not let me initiate a takeoff.

I have used batteries in cold climates in the past. I know how temperature affects both current output from batteries and future usability. I’m impressed that DJI has built in this feature to their firmware.

DJI Phantom 3 Standard

DJI has been the standard drone that people visualize when they think of consumer drones for the past several years. It’s a white quadcopter that comes with a white remote control.

This drone is the camera platform I was hoping for when I got into drones three years ago. The flights are very automated, the camera controls are fully integrated, and I can start flying in a new location with very little setup time. The picture below was taken to demonstrate how close the drone came to returning to its launch location and automatically landing after flying over a thousand feet away from where I was standing. The drone had taken off from on top of the ring, and it landed less than 4 feet from the same location.

In early March DJI dropped the prices of their entire line, convincing me to buy the least expensive unit, now on sale for under $500. I ordered it on March 18th, received it on March 23rd, but didn’t successfully fly it until March 29th.

I live in downtown Seattle. I didn’t want my first flight to be anywhere that would draw excess attention. I’ve been flying drones for three years now, and have grown accustomed to things going wrong. I’d planned on flying at the RC field I regularly visit on the evening of  March 24th. When I got there, first I was not able to get the drone to power on, then when I figured out how to do that, I was forced to do a firmware update before I could fly. By the time I’d got all that out of the way I was running late for a meeting. I decided that the safe thing was to put everything away until my next opportunity.

The Phantom 3 Standard is delivered with two sets of propellers, the transmitter / remote control, a flight battery, an AC battery charger, and a few small extra parts related to the camera gymbal.  It is designed to work with an iPhone or Android phone to both control the unit and see what the camera is doing. I don’t have either of those phones, instead I’m using a Google Nexus 7 tablet. The device connects to the transmitter via WiFi. While my tablet is connected to the transmitter it is not able to connect to the internet.

My first flight with the drone was in a Seattle Park. The battery reports that it can fly up to 25 minutes. None of my previous drones would fly for more than about 13 minutes. The controller app on my tablet has plenty of feedback about the battery condition.

Normal flight mode for me has been that I tell the drone to take off via the app. It takes off and hovers about 4 feet in the air. Then I use the sticks to fly the drone to a location telling it to go up/down or rotate left/right with the left stick, and moving horizontally with the right stick. I usually enable the camera in movie mode before taking off, and only take it out of movie mode if I want to take still photos. When I’m ready to finish, I can either drive it back near myself, or toggle the left switch on the transmitter to cause it to go into return home mode. I’ve got it configured so that it will be at least 100 feet above the ground during return to home mode, which is good enough to clear most trees, but I make sure that’s true early in my flight just in case. If the drone loses contact with the transmitter for more than three seconds it will enter return to home mode.

After owning the drone for one month, I also purchased the DJI backpack specifically designed to carry the drone. It has been what really makes the drone fun for me because I can store the drone in the backpack, knowing it’s fully protected, and easily grab the entire thing and throw it in my car to go somewhere that might have interesting things to photograph.

 

FrSky X4rSB Receiver controlling Eachine Racer 250

I wanted to use S.Bus communication to connect my receiver to my new Eachine 250 
Racer drone. I wanted to be able to remotely control the lights on the drone. I wanted to bring back telemetry from the drone to my transmitter. All of those are possible with the X series receivers from FrSky.

I’ve used the X8R receivers in the past, but I bought an X4R-SB receiver specifically for this drone.

In it’s default configuration it will output PWM on the pins for Channels 1 through 3 and S.Bus on the 4th connector. It has a separate input connection on the side for S.Port telemetry devices and an analog data line.

By putting a jumper on the signal pins, as shown in the picture above, during the binding process, the output is changed so that CPPM channels 1-8 are on the first port, PWM Channel 9 and 10 on the second and third ports, and S.Bus on the fourth port.

I’ve got the S.Bus connection going to the main port on my CC3D flight controller, a cable to control the lights on the third port (channel 10) and the first two ports remain unused. I have the momentary switch SH on my Taranis configured to control Channel 10. Toggling it cycles the LEDs on my Eachine Racer through the  off and on colored states.

The telemetry cable is connected first to a FrSky SP-GPS – Smart Port GPS Sensor (GPS-V2) and daisy chain connected to a FrSky SP-FLVS – Smart Port Lipo Voltage Sensor.

The GPS Sensor is a new item in my arsenal. I’ve used GPS chips connected to my flight controllers in the past, which allow the flight controller to direct its flight position using GPS. Since this is not connected into the flight controller, it’s purely a toy, though it may help finding the drone if I get confused and crash it away from myself. The last data received in my transmitter remains on the display, which I could then use to assist my search for the drone.

The voltage sensor connects to the balance plug on the battery, allowing me to monitor the state of the individual battery cells during flight, as well as having low battery alerts reported on the overall voltage.

For installation of this receiver in my drone, I’d come across a 3d model for a holder. I had never used a 3d printer before, though I’ve been fascinated with them for several years. I realized that Windows 10 has a 3d Modeling program installed by default, 3D Builder, and that it can print using an on-line service.  Because the service accepts the file and tells you how much it is going to cost delivered, this was an easy first try. I downloaded files for both a battery protector tray and the previously mentioned receiver tray, merged them into a single model file, and had them delivered for $27.15. Other than the time involved for the delivery I was happy with the result. I submitted the order on 4/26/2016. I received notice that it shipped on 5/10/2016. It finally arrived on 5/13/2016.

The design here has the receiver extending in the model over the flight controller and under the video transmitter. I’m not positive that I’m going to use the battery tray. If I don’t use it, I just need to get screw extenders to install the receiver directly above the flight controller.

Eachine Racer 250

I decided to get into the FPV Racing Drone scene and found this unit available in an almost ready to fly version for $140.

Almost ready to fly means that I need to add my own transmitter and receiver. Because it’s FPV, it also means that I need my own video receiver and display.

I have an FrSky Taranis transmitter, several compatible receivers, and a set of Fatshark Attitude V2 goggles,  so when the model arrived, I expected all I would need to do was charge the battery and it was ready to fly.

It turned out it was slightly more complicated, but the past three years of playing with drones meant that it wasn’t too involved.

First I found a useful wiki page dedicated to the racer, with plenty of information. It allowed me to understand that I’d got version 5 of the racer, with the difference from version 4 being that they’d removed a safety tray that kept the battery from crushing the flight controller.

I figured out that to use S.Bus to communicate between my receiver and the flight controller, I’d need to download software to my PC, connect the PC to the flight controller with a USB cable, and configure it’s inputs. The instructions I found all referred to OpenPilot. OpenPilot is an open source project that is now defunct, including the domain name itself not going anywhere. The replacement project that is functionally similar, is LibrePilot. I believe that http://opwiki.readthedocs.io/en/latest/user_manual/index.html is the old documentation from the OpenPilot project, while the LibrePilot home page has links to all of the new project.

After downloading LibrePilot and installing the software on my PC, I couldn’t change the settings on the firmware that had shipped on my drone without upgrading to new firmware and resetting all of the configuration.  After some hesitation, I allowed it to upgrade, then followed the wizard to configure the new firmware. I was impressed at the ease of setup, and later when I flew the device, it proved that the defaults worked nicely out of the box.

The original firmware had a rose icon, while the new firmware shows a warning icon. That could mean something important, but I never found any mention and the system seems to be working correctly. You can see that the drone shipped with a firmware dated 2015-03-12 and the new version is dated 2015-10-21.

Connecting the receiver to the flight controller using the S.Bus connection required using the MainPort connection on the flight controller. An appropriate cable shipped with the device that included 4 wires, colored black, red, green, and yellow. For S.Bus operation, the green wire is not used. I removed it from the flight controller side of the cable. When connecting to the receiver S.Bus, Black = (-) Red = (+) Yellow = (Signal).

My goggles only support 8 channels. The drone video transmitter supports 32. Finding a match required a bit of reading, and then deciding on what was least likely to cause conflicts with other people near the field I regularly fly at. I chose D7 on my transmitter and CH6 on my goggles, which worked out to 5840MHz.  The newer version of my goggles supports 32 channels. (8 channels, on each of 4 bands.)

I found that http://www.rcgroups.com/forums/showthread.php?t=2266883 has a very nice explanation of the frequency bands used for FPV including details of how they overlap and recommendations for which frequencies to chose for the least interference between racers. It includes a google docs spreadsheet that’s been color coded to have the frequencies sorted in ascending order and make the bands more visible.

I got the video transmitter and receiver in sync by selecting the channel on my goggles, then cycling through all of the possible channels on the transmitter until I got the clearest video picture. My goggles auto select NTSC or PAL depending on the signal they receive. A friend using a full sized monitor wasn’t as lucky. That’s how I figured that the Eachine Racer 250 ships with a PAL camera.

The Eachine Racer 250 has a pair of bright white LEDs on the front, one on either side of the camera, and a LED lightbar on the back. The LED light bar on the back can be cycled through a series of colors by sliding a power switch located on the left side of the main board that turns all the LEDs off and on. There is also a two pin cable connector that can be plugged in to a receiver PWM output allowing remote light control.  To use remote light control, the local switch on the drone must be in the OFF position.  I’ll write more about this in a separate post.

After going through the LibrePilot setup wizard and putting the appropriate propellers on each motor, the racer flew completely as expected. It’s very responsive, and also very resilient to the basic crashes I’ve had so far.  The biggest learning experience for me has been to add throttle when I think I’m going to crash on the ground. With my larger drones, I’ve wanted to stop and recover the drone when it hits the ground. With this drone, it is much more likely to bounce and be able to recover itself if I can get it off the ground.  I recommend this drone as a good entry into the FPV racing drone scene. I’m sure that there are plenty of drones that are more resilient or responsive, but there’s also plenty more that can be spent than I did on this.

Flashing ESCs on Hobbylord BumbleBee

I bought a Bumblebee Quad from a local hobby shop a few months ago, and when I finally got around to trying to build it with a proper autopilot found that it’s ESCs used a protocol called UltraPWM that is a very uncommon protocol.

I came across this page, https://github.com/sim-/tgy/issues/13 , which leads me to believe that I should be able to flash the ESCs with a simonk tgy firmware and use the hardware I already have.

I came across a cable from hobbyking that is designed to make contact with the surface mounted atmel device and allow programming without any soldering or desoldering. http://hobbyking.com/hobbyking/store/__27195__Atmel_Atmega_Socket_Firmware_Flashing_Tool.html It was designed to be used with an atmel programming device that they also sell http://hobbyking.com/hobbyking/store/__27990__USBasp_AVR_Programming_Device_for_ATMEL_proccessors.html and so I thought I’d be good to go. The cable cost $20 while the programmer cost $4, but not needing to solder anything was a very positive solution for me.

USBasp AVR Programming Device

Atmel Atmega Socket Firmware Flashing Tool

What I didn’t recognize until it all arrived was that Hobbyking has updated the USB Programmer to use a 6 conductor connector, but not updated their programming cable from the 10 conductor cable. The message boards on hobbyking discuss the change, and have pinout descriptions, but it’s been very frustrating because getting the parts to do the correct wiring has not been as simple as plug and play.

Atmega contact points

Atmega contact points

Cable Pinout Description

This has been extremely frustrating to me as the parts I ordered were billed as no soldering required, but could not be simply plugged into each other.

Pelican Case for my UAV

I live in an apartment. I need to store my UAV easily, I need to transport it easily, and I need to keep everything together. This is what I bought in an attempt to solve those three problems with my primary platform.I ordered a Pelican STORM IM2700 case in bright yellow. It’s got three layers of pluck and place pre-scored foam that I’ll be removing to fit my quad, the transmitter, batteries blades, and hopefully a new battery charger as well. 

Pelican Case with Quad and Transmitter

Pelican Case Top

Pelican Case Upright

Pelican Case Side

There are three layers of foam in this case. I’ll probably write more after I rebuild my copter and cut the foam to fit.

File a flight plan before takeoff

Always think through what you are going to do before you take off.

Broken Quadcopter

I had decided that I wanted to try the Follow-Me option in AndroPilot. Turned on my Taranis transmitter, but then left it sitting on the bench with the throttle down, and all the switches in default positions. I connected the 3DR radio to my Google Nexus 7 running AndoPilot. I hit the button on the tablet to arm the drone, and took it off entirely from the tablet. I was flying using the virtual sticks on the screen of the tablet, which was not extremely intuitive because there’s no tactile feedback on the tablet. I’d raised the drone up to about 40 feet, and was trying to find the button to attempt follow me.  It didn’t appear to be moving towards me, or doing anything very predictable. My friend near the bench asked what it took to take control from the RC transmitter, and I said just start flipping switches.  I continued to fly for about another 30 seconds when I asked him to flip return to launch. (I’ve got that set on a switch of it’s own, using channel 7 of the transmitter.)  He was getting concerned because I’d drifted halfway to the trees, and putting the copter in the trees 40 feet up was likely to be a total loss. He flipped the flight mode switch going to loiter. The copter stopped and tumbled out of the sky.

Afterwards he pointed out that before a flight we really needed to discuss what was supposed to happen, and what he could do to recover before the flight begins.

The reason the copter fell out of the sky was that he changed the flight mode without moving the throttle from zero, so when the copter took over it dropped the throttle and fell out of the sky. If he’d just changed the RTL switch things probably would have been just fine. My transmitter is set differently from his. I’ve got all 8 channels configured, with channel 7 being it’s own switch that only deals with the RTL command. He’s got an older firmware and uses RTL as one of his flight modes.

I asked for one thing to happen, and he did something else. He didn’t know exactly what I wanted, and by the time I needed it I wasn’t in a position to explain it quickly. The broken parts can be replaced for $15 from the original place I bought my X, or I can use another supplier and get other parts. I’ve bought an entirely second frame already with nothing mounted on it for only $12 so I might go that route instead of ordering more parts, or I may move parts to run on my new BumbleBee platform.

Hobbylord Bumblebee-S

I bought a new drone platform this weekend. I was in a hobby shop and there was a Bumblebee that had been left on consignment for sale. I liked the look of it, but hoped to do more flying of my existing drone during the day so left it there. While sitting at the flying field waiting for the rain to clear I did some more research on the unit and decided I wanted to get it. I called back, made and offer, and it was accepted.

I picked up a BumbleBee that included the motors and ESCs but no control board or power distribution board. It’s a nice design that folds to a much smaller space for transport. The power connectors to the ESCs seem to be red shrouded connectors that I’ve heard commonly referred to as JST connectors. A little research points out that JST is the likely manufacturer of  the connector, but that it’s simply one of a range of connectors they sell. http://en.wikipedia.org/wiki/JST_connector.

I’ve got my APM board that I retired from my primary UAV when I decided to buy the Pixhawk, so hopefully with the simple addition of a power distribution cable and my other existing hardware I should be able to have a second flying drone.