blitzen's blog - RC Groups
blitzen's blog View Details
Posted by blitzen | Jun 22, 2018 @ 11:50 AM | 1,558 Views
Last night I was out flying after dark again. I’m still amazed at the view through the goggles. The twilight appearance of everything is erie. The sky has been clear which helps the visibility. Of course where the man made ambient light is stronger, there is less noise in the image. My little 1S drone is quiet, unobtrusive and dimly lit. I’ve spotted some wildlife around neighborhood. A bat catching bugs under a street lamp and a skunk rummaging in the dark recesses. A few blocks (300m) down the avenue, the light from the bars and restaurants looks very bright. I’d like to checkout the “wildlife" down there in a future (late night) adventure. Tonight’s forecast is cloudy and I’m interested to see the effect of that.
Posted by blitzen | Jun 15, 2018 @ 10:29 PM | 1,674 Views
Tonight was the first time I've tried flying FPV outside at night. I flew a little brushless micro with a very inexpensive AIO VTX/Cam. The camera shows a grainy, washed out image in low light indoors. Outside it's grainy too but I could see pretty well. The resolution is poor. I'm in the camera's view but I look like a fuzzy blob in the picture. There is a lot of light pollution and the camera picks up on it. With the camera pointing towards Manhattan the sky is actually bright. Also, there is some color to the objects. This was about 45 minutes after sunset. To my naked eyes it was dark out there. Anyway, this is something I want to do more often.
Posted by blitzen | Jun 12, 2018 @ 12:59 PM | 712 Views
2 cups of coffee. New batteries and a beautiful spring morning. New power for the goggles and transmitter too. I was flying fully charged.
Posted by blitzen | May 25, 2018 @ 01:50 PM | 1,470 Views
I had been reading about building RC electronics like ESCs and receivers. While beyond my ability, I think it is interesting to read about what makes these things work. The fishpepper uSKY receiver was of particular interest to me because of the 10mm by 12mm size. While the tiny SBUS receiver started as a hack/project, assembled versions had become available here and there. I had come across a professionally assembled version from a factory in China. It looks identical to one now sold on Banggood. Anyway, the receiver operates at 5V. Compatible with the FrSky D8 SBUS protocol, binding to the Q X7 transmitter was simple. The assembly is neat, clean and a bind button has been added. The antenna wire is a generous 144mm long. So it was trimmed to an appropriate size for my quad. After insulating with heat shrink, the tiny receiver was tucked in between the standoffs of a 16mm stack. First tested inside, the uSKY worked reliably. Outside, the control distance is said to reach 200m. The 25 mW FPV signal only carries about 100m+ but the RSSI was still strong at that point.
Note: Betaflight 3.3.1 CLI syntax "set serialrx_inverted = ON” now replaces the old "set sbus_inversion = OFF”
To purchase a fully assembled receiver go to Banggood.com and search for 8CH-SUBS. Yes, they misspelled SBUS in the URL/description. Or, for more information about the open source check out https://fishpepper.de/projects/usky/
Posted by blitzen | May 19, 2018 @ 03:28 PM | 1,468 Views
About a month ago I wrote about a micro size drone kit. The drone's frame isn’t so small (90mm) but the whole thing only weighs a few grams more than a “Tiny Whoop”. I don’t have a yard or a field nearby. But, I’ve got a bench outside my building and that is where I’ve been. I was astonished by the drones outstanding performance outdoors. The FPV signal carries for just over a block (100m). It’s great fun flying around the neighborhood. Over the past few weeks the configuration has been tweaked to the point of perfection. The combination F3 flight controller and 4 in 1 ESC is working flawlessly. The 0703 15000KV brushless motors are very quiet and after the flight they're still cold. I believe this is due to the DShot 600 ESC protocol and Dynamic Filtering in Betaflight. The motors and 3 blade props produce an abundant amount of thrust and the drone could afford to gain a little weight. So today, I’m building another Happymodel Trainer90 and I will continue to experiment.
Posted by blitzen | May 13, 2018 @ 08:02 PM | 1,299 Views
This is very similar but not identical to another flight control board with the same description. The package includes a battery connector and buzzer. The lowest price was from Banggood (on sale $23.49).
The Fusion X3... is a compact, lightweight option for 1S brushless multi rotor DIY. This is not a corner mount “whoop” style board. Instead, this is rectangular and typically mounted on 4 standoffs attached to a frame part. It can handle a variety of 1S brushless motors and 3.7V and 3.8V LiPo batteries. Both the flight control and ESC are configurable and have fairly recent and stable versions of their firmware installed. There is 5V for a receiver (PPM, SBUS and IBUS), VTX, buzzer and LED. But, no 3.3V for a Spektrum receiver. Soldering the peripherals and motors takes forethought because there are connections on the top and bottom of the board. The 5A ESCs are big enough to handle the current that passes through 06xx and 07xx motors.
CPU: STM32F303CCT6 (72MHZ, 256K FLASH) MPU-6000 6DOF (SPI connection)
Power supply: 3.7V 1S
Voltage detection, alarm and 5V/1A step up regulator
Betaflight programmable OSD, buzzer and LED Strip
Receiver protocols: PPM, SBUS, IBUS, Spektrum DSM2 / DSMX, 1024/2048.
Betaflight Omni 3.2 firmware
BLHeliSuite programmable BLHeli_S 5A ESC (6A 3 sec. peak) Supports D-shot150, D-shot300, D-shot 600, Oneshot125, Multishot, PWM
Measures 28mm x 30mm and weighs 3.1g.
2.5M screw hole spacing: 16mm x 16mm
Posted by blitzen | May 05, 2018 @ 01:22 PM | 1,413 Views
It is spring here in the northeastern U.S. Yesterday morning the sky was cloudy and the air was warm and still. I finally had the perfect conditions to fly a small ultra light quadcopter I had built. The power supply is relatively small so I wasted no time in testing the quadcopter's abilities. The performance was no less than spectacular. I felt elated. Returning to home and descending from a high altitude the quadcopter clipped a thin branch of new growth and spun out of control. The quadcopter was hung up in a leaf cluster helplessly looking down from the 40 foot tree top. Sadly, I sat there on the bench and watched as the battery quickly expired. I went inside and chalked it up as a loss. It would take a strong gale to free it from the entanglement. If it fell at sometime in the future, finding it would be unlikely. All that being said, a dry, and gusty wind kicks up overnight and blows it out of the tree. The next morning, I find it resting right side up, undamaged and in the same spot it took off from. I think that goes beyond being lucky.
Posted by blitzen | May 03, 2018 @ 08:12 AM | 2,043 Views
The cost to build was less than $90 US. That includes the miscellaneous parts, spare props and 4 batteries. I’m happy with the results. It is nimble and resistant to damage in closed spaces. Out in the open, it is fast and wind conditions aren’t a problem.
Cutting a lightweight frame helped to offset the weight of crash guards. Using a diamond wheel and bits, it was easy to accurately cut through thin (2mm) carbon fiber leaving clean sharp edges on both sides. Bright yellow crash guards are attached to the simple X frame supporting a 20mm flight control and ESC stack. That consists of a Betaflight 3.1 Omnibus F3 6DOF Mini Flight Controller (Omni 3.3.1 firmware). And, a 6A 4X (DShot 600) ESC that controls the 1103 8000 KV brushless motors. They're spinning 4 blade 2035 propellers. The tiny 10mm x 12 mm S-BUS telemetry receiver (D8) weighs 0.8g. 100 meters is about the maximum reliable control distance. An AIO 25 mW VTX/600 TVL camera has video in and out for OSD. The VTX/cam is the smallest available measuring 13.9mm x12mm, 3.5g. The weight of the quadcopter is 66g including the battery. It is a 2S (7.4V) 350mAh LiPo. Flight times are about 6 minutes.
Posted by blitzen | Apr 14, 2018 @ 09:40 AM | 1,747 Views
This is the 24 gram, 0703 KV15000 brushless motor version of the Trainer90 BNF kit. In the box of parts I found 2 sheets of paper showing wiring diagrams and the steps needed to bind the receiver to a transmitter. The model is assembled as shown in the pictures. It is important to note that the bottom end of the motor shafts must be supported while pushing on the props. I've already made a few modifications. The 3D printed camera mount was replaced. The receiver board is now part of the stack. And, snazzy new 3 blade props. The power supply is a "Whoop" style stick battery so the fun is interrupted every few minutes. The main board is a combo flight control and a 4 way ESC that eliminates wiring and compacts the setup. Solder connections are on the top and bottom of the board. And, inboard mounting holes let the board fit onto the 16mm x 16mm stack. It overhangs but the ESC solder pads conveniently line up with the frame arms. I’ve tightly wrapped the slender arms with vinyl tape which also protects the motor wiring. Otherwise, the electronics are typical for a micro these days. Using Betaflight OSD, adjusting the PIDS and rates while flying was faster and easier than going back and forth to a computer. I really like that feature. My configurations and transmitter setups have gotten more sophisticated lately but that is a subject for a different post.
Flying around the apartment, it is safe and durable even without propeller guards. But, I fly away from people, pets and delicate items. It has more power than needed. Outdoors, it is light, airy and beautifully acrobatic. Now the Trainer90 name makes sense to me.
Posted by blitzen | Mar 23, 2018 @ 11:08 PM | 1,409 Views
I have a little quadcopter that has brushless motors. The 2" props are like miniature buzz saws. I want to protect people, pets and the bric-a-brac. So I bought a prop guard.
Confident that the drone is now a low-level danger. It's sitting on the living room floor ready to go. Little did I suspect, the battery loop fastener had partially stuck to the plush carpet. On take off the fastener ripped free unevenly, rolling the quad. Faster than I could blink, it was upside down on my bare foot. The scratches only bled a little.
Posted by blitzen | Mar 16, 2018 @ 07:13 PM | 1,237 Views
I learned something today. Recently, I found this toy camera drone in the clearance section of a store. The box was undamaged, factory sealed and marked 75 percent off. I bought it.
"Altitude Hold" is printed on the package. That means the left stick, up and down is spring centered. It is intended to make the quadcopter ascend or descend to a "locked" altitude. Take off, flight and landing are all managed by the flight controller and it's sensors. I was surprised to find out this feature is greatly effected by the weather. The altitude hold worked amazingly well when the air pressure was steady and low. Today there were fast changes in the weather with rapid air pressure changes. The drone was completely out of control at times. Basically grounded.
Posted by blitzen | Feb 27, 2018 @ 12:11 PM | 4,065 Views
This modification requires a little soldering skill and doing goofy stuff like this requires a HAM license.
Take a crumby toy and fix it so that the signal is efficiently transmitted. A center fed dipole has a 2.1 dBi gain. Theoretically it should send the signal twice as far as the original. In reality, it does better. An omni-directional antenna held vertically emits an almost perfect doughnut shaped radiation pattern. If the dipole is turned horizontally, the radiation pattern shows the signal strength is in front, back and most importantly up in the air. There is no strength side to side but we can easily change the direction we are facing. RF is wasted as some of it is traveling behind us and towards the ground.
The tools are a small soldering iron, electrical solder and flux. A small wire cutter, finely calibrated ruler and an exacto knife. A drill to make 2 small holes (each slightly off center) in a popsicle stick.
The scavenger hunt. A length of thin flexible coax cable measuring at least 17.5 cm. That cheap audio cable from the broken Hi-Fi or VCR will do nicely (RCA plugs removed). Solid conductor telephone, doorbell or alarm wire. 2 pieces cut to 31mm. A bit of string or a mini plastic cable tie. Sticky tape and a clean popsicle stick.
Note: The insulation on the coax is soft and melts very quickly. It's tricky to make a solid join without melting the dielectric. The two 31mm wires should be positioned with a slight air gap between their ends.
Posted by blitzen | Feb 26, 2018 @ 09:30 AM | 1,914 Views
A middle aged woman comes in and buys a complete FPV multi rotor RTF set of moderately good quality. This was a present from a wife to a husband. She explained that her husband already had experience with a “camera drone”. The outfit was costly as it included all the components and accessories. A day later, the woman returns. I thought it was something trivial but it was a request for another “drone”. She said, “It flew off into the woods five minutes after he got it. We couldn’t find it”. I was curious as to who’s idea it was to get another. I didn’t ask but during the conversation I became very suspicious that the “drone” wasn’t for her husband at all. So, I suspect a suburban housewife is sneaking off with her “drone” while the kids are at school. I wonder if her husband knows.
Posted by blitzen | Feb 11, 2018 @ 07:59 AM | 2,632 Views
This question I still see so often answered incorrectly. Do I need a FCC license to use an FPV transmitter? To answer that question correctly, I’ll quote directly from a portion of an article in the April 27, 2017 Model Aviation column titled FCC Concerns by Tony Stillman. My reason and concern is that misinformation might dissuade a novice from flying as licensing may be too much to swallow at first.
"Typical model use today would be in the areas of FPV drone or fixed-wing racing. A commonly used frequency is 5.8 GHz. In order for an unlicensed person to use this frequency band, the FCC only allows specific power output maximum levels.
In this case, they use a complex calculation based on the measured output of the device from a specific distance away. If the device falls below a certain threshold, the FCC requires an FCC identification number on the device itself. This marking indicates that the transmitter can be legally operated without a FCC license.
These items have been tested and determined to have low enough power levels, and a fixed antenna as part of their design, so that they will not be an interference threat to other users. Typically these will be 25 milliwatts (mW) of power or less, but the actual determination process is complicated.
However, if the item’s output power is above this level or the antenna is replaceable, there will not be an FCC identification number on the product, and it will require the proper FCC licensing to operate."
Posted by blitzen | Feb 10, 2018 @ 10:02 AM | 2,875 Views
As far as the hobby goes, I had a bad day yesterday. It seems everything I touched turned into a steamy pile.
I just couldn’t get it together and busted up a quadcopter on the first pack. The bottom frame part, 3 props, 1 ESC, 1 motor, CMOS cam and FPV antenna are all broken. It was interesting to watch the image sensors burn up. It looked like blood slowly dripping down the screen. Unfortunately, the goggles weren't recording.
Starting the repair job late at night was a disaster. Blurry eyes, clumsy fingers and bad decisions. I should have waited. Stress and fatigue made everything worse.
I haven’t gone back to take a look at it this morning. I think I’m just going to sit here for awhile and enjoy a late breakfast.
Posted by blitzen | Feb 05, 2018 @ 12:49 PM | 2,193 Views
A package of BetaFPV 40mm 4 blade props came in the mail yesterday. They are replacements for my ducted (75mm) frame kit's three bladed props. Fitting on a 1mm shaft, they are to be used with either 0720 or 0820 brushed motors. The benefit is increased lift. I felt a change in the throttle immediately on take off. During the flight the throttle position was generally lower than before. This is an inexpensive upgrade that really works.
My hope was that getting these might lessen or change the pitch of the annoying noise the quad makes. Unfortunately changing the props has had the opposite effect and the quadcopter sounds even more bothersome to me. Flying in my apartment, the noise level is unacceptable. Before I dismantled the quadcopter, I wanted to answer some unknowns.

Experimenting with 0720 Brushed Motors
Changing to a “better" motor brand was a waste of time and money. While on the bench, the new motors ran slightly smoother. There wasn’t any noticeable difference once the props were attached. Maybe they will be longer lasting than the Apex 17500KV motors but I doubt it.
A set of generic unrated 7mm x 20mm motors were slower but had just enough power to get the job done. I didn’t attempt flips or rolls. Almost as expensive as faster motors, choosing the faster makes sense.

Experimenting with 40mm, 4 Blade Props
According to physics, cutting 2 blades off of the 4 blade props should decrease lift. I’ve tried it and it does. So, I wouldn&#...Continue Reading
Posted by blitzen | Feb 01, 2018 @ 10:56 AM | 2,122 Views
My junk draw is deep. It holds miscellaneous pieces and parts stripped out of things that quit working. I was in there looking for something and while rummaging through it all I got distracted. After a few minutes, I found enough stuff to build a small FPV quadcopter.

Because some solder needed to be cleaned up and the cam needed to be fixed, the assembly took a little longer than usual. I was so lucky finding all the parts that fit together. Even the motor wires were just long enough to reach.

The quadcopter is feather weight with more than enough thrust and it’s controllable too. The FPV signal is strong and video quality is good. I’m really happy and I think it looks okay. That’s surprising as it is made of used parts from 8 different quads.

Basically it’s a 90mm FPV quadcopter with an F3 brushed flight controller and 8.5 mm motors that I didn’t know that I had.
Posted by blitzen | Jan 26, 2018 @ 07:44 PM | 3,301 Views
I recently installed my own pieces and parts into an LDARC Tiny 7 Frame Kit. Until I flew the quad around room, the experience was unremarkable. But after a few tests there was something familiar about it. I couldn’t tell what it was. The rotors seem to make a unique sound that almost triggers a memory. Where have I heard that noise before? After a few more battery charges I start to get the feeling like I’ve flown this quadcopter at sometime before. Even the way this quad handled in the air gave me a feeling of deja vu. Later on in the evening I went back to it and plugged in a battery. It was dark and the quad came to life with a phosphorescent glow. The lights filled in another part of my memory and then it all came back to me. That noise comes from the Cheerson CX-31 “Alien Head” flying saucer! I went to my collection to check it out.
Bingo! The CX-31 and Tiny 7 use the same 40mm 3 bladed props with similar 0720 motors mounted in a ducted propeller frame..
Both are 73mm OC measured diagonally motor to motor. The suggested power supplies are 450 to 500 mAh.1S LiPo batteries.
The old Cheerson “Alien Head” was designed for show. Surrounded in a ring of lights it is a great night flyer. It has been unused for a couple of years but everything still works. The newer Tiny 7 is obviously designed for FPV racing but it has some of the same inherent flight characteristics as the CX-31. And, it sounds the same.
Posted by blitzen | Jan 15, 2018 @ 01:09 AM | 2,235 Views
Eachine BeeCore F3 Flight Controller with On Screen Display
& 2.4G FrSky compatible 8 Ch. SBUS Receiver
Kingkong Tiny 6 Frame Kit*
31mm 4 Blade Propellers
Crazepony 19000KV Brushed Core-less (0615) Motors
700 TVL CMOS FPV Camera
25mW 5.8G 48 Ch. VTX
3db Dipole Antenna
Micro JST 1.25 Battery Connector w/ silicone wires**

Easy receiver binding and initial flight controller setup. Pre-configured with some basic settings.
On Screen Display including RSSI and VBAT monitoring
Reliable gyro and accelerometer
Perfectly balanced CG
Weighs only 20.5g.
Protected camera and indestructible antenna!
Better chance of finding clear reception with a 48 Channel VTX.
Designed with 10A FETs for larger battery and motors (and a slightly bigger frame).
Minor configurator, firmware and flight control /receiver bugs.
High speed motors need PWM adjustment to get rid of noise.
VTX/Cam has a tendency to over heat if air isn't moving through the canopy.***
Quad sits low on the ground. Needs a Micro USB 2.0 Data Sync Cable with a right angle connector.

* The BeeCore board fits on this Inductrix style frame correctly. Mounting the board on an E010 style frame, the battery holder is in the way of the USB connector.
** Tattu 220 mAh 45C LiPo batteries w/ micro JST 1.25 connector. (Weighs only 5.5 grams.)
*** VTX power leads tacked to battery pads. Avoids power from USB when sitting on the desk.
Posted by blitzen | Jan 03, 2018 @ 10:35 AM | 2,012 Views
What you see here is my New Year resolution. How long will it last?

The subject is FPV Micro Multi Rotors. The quadcopter size is usually less than 130mm (measured diagonally from motor to motor). Inspired by a popular model, I enjoy building my own version of it from off the shelf parts. DIY isn't a cost saving strategy. Although there is knowledge and personal satisfaction to account for.

Old man Winter is blowing his icy breath. Spring is still months away. This tiny FPV racer is my latest. Because of the holidays, I had to put off the processes of configuration and tuning until now. More about the little "Stinger" later on.