Saturday, May 28, 2016

Radio Signal Latency

Transmitter-to-Receiver latency is a much-cited metric when discussing radio systems.

Andy Kunz, a member of the Spektrum development team, wrote a couple of posts going into great detail about how latency is measured and what it means.  Because RCG posts get hard to search, I'm capturing them here for posterity.

I've moderately edited from these posts and a couple in between (quoting people asking questions).

Thanks Andy!

Friday, May 20, 2016

DIY FrSky Receiver

Here's how to make a FrSky compatible receiver with an Arduino and CC2500 radio.

It's also sold as the AirWolf models 1 and 2.  I'm ordering one  to test it out.

Tons of technical information at the link.

blogodex = {"toc" : "AirWolf"};

Saturday, May 14, 2016

A Couple of UMX Radian Videos

Here's a couple of videos of my UMX Radian, a really sweet plane.

Quiet morning flying at the Berkeley Marina

Here it is with a wing mod that makes it into a really slow flyer.

And pretty sweet indoors.

blogodex = {"idx" : ["UMX Radian", "Videos"]};

Saturday, May 7, 2016

Taranis Sound File Formatting

Here's the incantation to generate a sound file playable on Taranis.

ffmpeg -i myfile.mp3 -ar 32000 -ac 1 -acodec pcm_s16le myfile.wav

In human being terms:

- 32,000 bps sampling
- mono
- PCM signed 16-bit little-endian

well for a certain type of human being anyway.

blogodex = {"toc" : "Taranis Audio", "idx" : ["audio", "ffmpeg", "deep, dark magic"]};

Monday, May 2, 2016

An interesting RCG note from Springer at Model Plane Foam. They're a pretty cool outfit... they asked the manufacturer of Dollar Tree foamboard for a foam more suited to model building.
Model Plane Foam is available from it is the same recipe as the latest Dow fff, white, no film or printing or perforations. Shipping to AZ is high, but it is still typically less than Depron.
Here's the thread with the history and info on it:
Adams says that the dtf formula is different from the Dow formula which is what we get (less the pigment, of course). A grade MPF has a fine skin with almost a rubbery feel to it that is decently dent resistant. A big part of the difference in both stiffness and durability comes from that skin.When the paper is removed the dtf surface is composed of open cells (no dense skin left at all) which is fragile and dents easily. So the difference in strength/stiffness is a combination of factors. Current A grade MPF is running between .2 and .23" thick, on the low side of the thickness spec.
I'm sure that a big part of the cost difference is shipping (I find it is awfully expensive to ship mostly air!), but process may also be a factor, if I understand correctly, Depron is extruded in flat sheets (probably why it has best flatness) wheras MPF and fff are extruded in a different process that has higher throughput, but sacrifices flatness (sometimes - it varies within a run and is one of the parameters we specifically ask them to control better than they do for fff).
As far as stiffness, density, etc. MPF is targeted at 2lb/cu. ft. From what I have seen of depron, it seems like similar density. Depron is stiffer but more brittle, which I attribute to the formula difference. One customer who made 3d plane kits loved MPF for his planes because a crash that would previously result in a bunch of Depron pieces was a non issue for MPF. He was one of those who milled away foam to make a girder structure in the foam sheet so the increased toughness was important.

blogodex = {"toc" : "Model Plane Foam"};

Saturday, April 30, 2016

SQ8 Hatcam Notes

 Got an SQ8 camera to try as a hatcam.  It has a nice clip system.  I made an adapter out of instamorph,  Even if the camera turns out to be a dud, I'm super impressed with how well the instamorph holds on to the brim of the hat.

I'll try it out "for real" soon and report back on image quality, etc. So far not too bad for $20.

I think I need to get a faster memory card though.  1080p carries about 15 FPS.

Some stats: 720p, about 6Mbps, 29.79 FPS; 1080p, a bit less than 15FPS.

The way I've got it mounted now holds the camera upside down.  Here's the incantation to flip the image and convert to h.264.  The duplicate transpose items aren't a type.

    ffmpeg -i PICT0002.AVI -vf transpose=2,transpose=2

blogodex = {"toc" : "SQ8", "idx" : ["hatcam", "video", "instamorph"];

Wednesday, April 27, 2016

April 2016 Shopping List

Here's what you need to get started.

Basic Idea:

  • Transmitter and Receiver
  • Airplane Electronics
  • Body Parts
Nice Starter Plane:
  • EZ-Fly

Transmitter and Receiver.

Get these from Aloft Hobbies, one of the best vendors on the net!

(to be continued)

Airplane Body

Here's the raw materials for the E-Fly Body.  For each body, you will need 3 sheets of foam, 1 carbon tube, and two pieces of steel wire.  I think severlthe shipping won't go

You can also buy the foam pieces pre-cut:

Power System


Here's some other stuff you will need

blogodex = {"toc" : "Parts List", "idx" = ["Beginner's Guide"]};

Saturday, April 23, 2016

Mini Drake Flying Boat

Got this from Hobby King... comes in a flat pack, gonna have to really glue it up old school!

HK Page
RCG Thread

Based on the original 1951 Drake.

Recommended bits:
    AeroLite or MicroLite
    Micro Control Horns
    Linkage Connectors
    1811-2900 Motor
    MultiStar 10A ESC (pre-BL Heli) (6A would be fine too)

Random RCG notes:

  • use two (2) #16 rubber bands to hold my wing on.
  • The CG per instructions is on the main spar for the wing. It should balance there when placed on your fingertips. 
  • Construction Notes

blogodex = {"toc" : "Mini Drake", "idx" : ["flying boat"]};

Thursday, April 7, 2016

60 inch OSG - One Sheet Glider

Completely uses exactly one sheet of $Tree foam.

The mighty Springer has a build thread.

blogodex = {"toc" : "OSG", "idx" : ["One Sheet Glider", "Springer", "DollarTree foam"]};

Tuesday, March 29, 2016

Arduino Current Sensing

Here's a current-sensing module from Sparkfun.  It's non-invasive, clamping around the wire carrying the current you wish to measure. I'm planning to use it to watch a particular appliance and see when it's on and off.

My initial plans are to attach it to an ESP8266 (Huzzah breakout), upload the measured current to thingspeak via a local wifi, and watch it from there.

Example apps:
(example 1)
(example 2)

blogodex = {"toc" : "current sensing"};

Friday, March 18, 2016

Tiny Shopping List

 $1.25    8x4 props (2)
 $0.00    theraband prop saver bands
 $0.19    JST pigtail, ESC side
 $0.72    2mm bullet plugs, male (3) (motor side)
 $0.72    2mm bullet plugs, female (3) (ESC side)
 $0.00    2.5mm heat shrink tubing
$6.46    9g servos (2)

$0.29    control horns (2)
$13.73    2S/3S balance charger
$14.40    3S 500 mAh LiPo batteries (2)

Monday, February 29, 2016

ReadiBoard EZFly

Over on rcgroups, user balsa or carbon shares some hints on making ReadiBoard EZFlys.  Check out his videos, you can see the great results he gets.

I make EzFlys out of ReadiBoard, both paper on and paper off. Single layer everywhere except the wing's leading edge will be double layer with the KFm, and the nose will be triple layer with the two nose doublers.

For a stronger, faster flying EzFly - I leave the paper on and scotch tape over all the edges. But the exposed paper will be susceptible to moisture. 

For a very lightweight slow and floaty EzFly , I cut out all the parts and then peel the paper off. I also use lightweight electronics and increase the wingspan to 40" for very light wing loading.

His Slow and Floaty model:

blogodex = {"toc" : "EZFly", "idx" : ["ReadiBoard"]};

Wednesday, February 3, 2016

Phantom Flash ROG

Here's the Phantom Flash from 1937.  It's an ROG ("rise off ground"), meaning that it takes off and lands, instead of being hand-tossed.

blogodex: Phantom Flash / balsa models;

Saturday, January 30, 2016

OrangeRX DSM2/X Modules

Here's the current state of OrangeRX modules.  There's a lot of discussion that the Devo-compatible module has problems with the Eflight UMX receivers.

OrangeRX DSMX / DSM2 Compatible 2.4Ghz Transmitter Module (JR/Turnigy compatible)
PRODUCT ID: 9171000302-0 

PRODUCT ID: 9171000536-0 

PRODUCT ID: 9029000274-0 

blogodex = DSM2 / DSM2, DSMX, modules, radios

Friday, January 29, 2016

GoldGuy's Slofly Simple Delta

Looks like a nice slow-flyer to build for beginners.  Based on the late Dekan's Simple Delta.

GoldGuy Says:

Twenty more square inches than my first 22 incher and one ounce lighter for a loading of 3 ounce per square feet at a 6 ounce RTF weight. It's a 8X22X17 with the elevon hinge line at 3 1/2 incher. Start off with the CG at 5 1/2" and then fine tune to taste.

Take your SD to the next level, the SSD will loop, roll, spin, snap, stall turns, harrier, prop hang, torque roll and flies inverted on rails, all this and no pitch sensitivity at any speed. Oh ya, and crazy climbing inverted flat spins the guys call 'the Dilbert' (?????).

Build it light, keep it tight.............

Here's the Simple Delta.  Details here, here, here, and here.

WS is 20"
LE is 7" long
LE to TE (hinge line) is 14.25"
Elevons are 2" wide
Fus is 8.5x1.75"
Try 5" as a CG start point from LE, mine works ok at 6" 
The Fin is 5" tall by 10.5" long.The Fin proper starts 8" from it's front and slopes back 2.5"
There are 3mmx.5mm CF flats on the leading edges....prevents damage from weeds!
There is also a 3mmx.5mm CF spar

blogodex: Simple Delta / GoldGuy, Dekan;

Thursday, January 28, 2016

Laminate recommended on RCG

Premium CP Laminating Film -- 3mm regular, 5mm heavy duty.

Premium clear gloss (CP) roll laminating film is a high-clarity, abrasion-resistant, low-melt, polyester-based film.  CP Laminating Film is a higher quality roll laminating film that activates 20-30 degrees cooler than standard polyester films. CP film is available in 1.7 mil, 3 mil, 5 mil, and 10 mil.  Standard widths are 9", 12", 18", 25", and 27".  The activation temperature is 210-230 degrees.

blogodex: laminate / supplies;

Monday, January 25, 2016

Some Skipper Notes

Courtesy of DrBamBam:

Stock Propeller: APC 6x4
Stock Motor - Turnigy D2826-6/2200kv

expo: 40% all       travel (up/dn, l/r)
Ail - high rates     60% /  60% (12mm / 12mm)
Ail - normal rates   40% /  40% ( 8mm /  8mm)
Ail - low rates      20% /  20% ( 4mm /  4mm)
Ele - high rates     60% /  50% (19mm / 16mm)
Ele - normal rates   50% /  45% (16mm / 14mm)
Ele - low rates      40% /  35% (13mm / 11mm)
Rud - all rates     100% / 100% (35mm / 35mm)

blogodex: Skipper / The Fleet;

Friday, December 11, 2015

DIY FrSky Rx

RCGroups user midelic has a DIY FrSky D8 compatible receiver, porting PhracturedBlue's Deviation work.

Canonical information page here.
Banggood is selling them here:

Airwolf F801
Airwolf F802

HobbyKing -- same?


DIY SBUS 16ch decoder

Some Reviews:

blogodex = {"toc" : "DIY Frsky", "idx" : ["midelic"]};

Tuesday, December 8, 2015

HobbyKing Wingnetic

EastBay RC went officially crazy at the HobbyKing Black Friday sale.  First up, the Wingnetic!


  • Build was simple, just glue on the fins.  Double check that the wings are glued on, some people report that they're not completely glued an were loose in flight.
  • CG is 240mm-250mm from the front of the spinner.  The manual says 205mm, which is incorrect.
  • a few clicks of up elevator (about 1mm) helps on launch.
  • Some people report 60% travel with 50% expo for low rates works well.
  • removable fins mod.
  • Demo7 shows how to laminate the wings.

blogodex = {"toc" : "Wingnetic" };

Saturday, October 31, 2015

Book Review: Aerial Photography and Videography Using Drones

 If you've been involved in drones for any length of time, you're probably already familiar with Eric Cheng's Aerial Photography

He's released a new book called "Aerial Photography and Videography Using Drones" which summarizes a lot of his experiences and is a great introduction to using a drone for aerial photography andvideography.

tl;dr: If you're a beginning drone pilot interested in aerial photography, you should buy this book immediately.  If you're an experienced drone pilot but would like some instruction on the photo/video side of things, it's got useful stuff for you as well.  If you like photo books with beautiful, thoughtfully composed material, ditto.


  • chapter 1: Equipment
  • chapter 2: Learning to Fly
  • chapter 3: Aerial Stills Photography
  • chapter 4: Aerial Videography
  • chapter 5: Getting the Shot: Real-World Stories
  • chapter 6: Flight, Policy, and Travel
  • appendix A: Resources
  • appendix B: Reference Material

Bonus Online Contents

You can access this material by registering your book on the website.  There's instructions in the book's introduction.

  • Chapter 1: Overview
  • Chapter 2: Exercises
  • Chapter 3: Dronie
  • Chapter 4: Toolkit (and Orbit)
  • Preflight Checklist
  • Resources

Beginning Pilots

Start with chapters 1 and 2.  That will get you into the air, with eight exercises that will quickly build your piloting skills. Be sure and follow along with the video exercises and you can watch Eric fly the moves.

Aerial Photographers

Chapters 3 and 4 are for you.  Eric talks a about the technical aspects, and then (what I found especially useful) lists some of the common camera moves, such as the crane, arc, and point of interest.  In the video supplement he give some hints on how to practice these so that you can use them smoothly and without councious thought, giving your maximum attention to the creative and storytelling aspect of what you're doing.

One excellent point of his presentation: you're telling a story, and the technical aspects of what you're doing are in support of the story you are telling.

Chapter 6 has some practical advice on travelling with and transporting your equipment, and some notes on flying legally.  This is a topic which is being continuously revised by various governments, so it's probably a good idea to check that the guidelines he mentions are still applicable in your location and time.

One interesting note:  he mentions that many people ask him about how high his aircraft will fly, but it's ironic that a lot of the best photography is from relatively low altitudes.

People who love beautiful photography

Chapter 5 is a collection of world-class drone photography.  Some of it's by Eric, and some of it by other photographers, both professional and amateur.  Stunning, Drop-dead gorgeous, etc., It's all splendid!

Note on reading the PDF version

It's obvious Eric has put a lot of effort into the layout of the book.  If you're reading the PDF version, be sure to

  • go into full-screen viewing mode
  • view pages as "side by side" or  as "two pages"
  • ensure that the right-hand page is odd numbered

Fixing your PDF version

Look at pages 142-143 of the ebook.  There should be one picture, with the beginning of chapter 5 .  If you see page 141 (with text) on the left, and page 142 on the right, you need to adjust your view of the pages.

With Adobe reader, this is easy (I'm told) to do... just move one page forward, and the left/right balance will be adjusted.

If you're on a Mac and using Preview, you'll need to do a bit more work.
  • In Preview, File / Save, save as "drone2.pdf".  Don't select "save as PDF" it will remove some of the imagery.
  • Open "drone2.pdf" in Preview
  • View /  Contact Sheet
  • Select the title page (not the cover) and delete it
  • Go back to "Two page" view and you should see the even numbered pages properly displayed on the left.

Book Link:

Aerial Photography and Videography Using Drones


Eric's a longtime friend of EastBay RC, and provided a complimentary copy of the book for review.

Tuesday, September 29, 2015

Great Micro Connector Resource

Micron Wings is a great resource for all things involving small models.  This page describes the battery and servo connectors to small models, along with details about each one.

The second and third are UMX and Hubsan.

Here's the servo connectors.

blogodex = {"idx" : ["Connector Mania"]};

Wednesday, September 9, 2015

The Joy of Free Flight

Here's a photo by Concord Model Engineer Lynn Price of a participant at one of the recent Free Flight contests.

Sometimes low tech is the most beautiful tech!

blogodex = {"idx" : ["free flight", "Concord Model Engineers"]};

Monday, September 7, 2015

DJI Intelligent Navigation, Part 1: The Menu

The first challenge in using Intelligent Navigation is finding the menu!

  • Have the unit flying in the air.  If the unit is not in the air, the menu will not appear.
  • Flip the flight mode switch (the three-position switch on the upper left of the remote) to the leftmost "F" position.
  • If you're in the air, the Intelligent Navigation menu will pop up.

blogodex = {"toc" : "DJI Intelligent Navigation"};

Sunday, September 6, 2015

"Intelligent Navigation": Interesting Thing Coming in DJI-Land

From an RCGroups post by blade strike of DJI Support, a pretty serious upgrade is coming.

"Intelligent Flight Mode", with the theme "Design Cinematic Shots Like a Pro."  I usually don't upgrade immediately, but this sounds pretty interesting so I think I'll give it a go.  Stay tuned!

Update: Downloaded, installed, and ready to fly!  Flight report upcoming...

Listed features are:
  • Waypoints
    "Set multiple GPS points, or Waypoints, and the aircraft will automatically fly to them while you focus on controlling the camera."
  • Point-of-Interest"Set a specific building, object or location as the Point of Interest and the aircraft will continuously cirlce around it while you record the perfect photos and video."
  • Follow Me (Phantom 3 only)
    "With Follow Me, the aircraft will automatically follow you and capture your every move from a unique aerial perspective."
  • Home Lock
    "Fix your controls to be relative to the Home Point. Easily pull back on the control stick to bring the aircraft back home, or push forward to fly farther away, no matter which way it is facing."
  • Course Lock
    "By activating Course Lock, the controls will be set to be relative to your aircraft’s current path. This easy navigation allows you to fly in a set direction as you fly alongside moving objects or across scenes."

Comments in the thread indicate that "Follow Me" won't be available for the inspire because of its size and relative power.

I'm intrigued by the comment that the firmware download will be through the app.  Does that mean we won't have to do the SD card beep-beep thing?  (Update: no, still have to do that.  It would be pretty nifty to be able to kick that off from the App!)

blogodex = {"idx" : ["Inspire 1", "DJI", "Intelligent Navigation"]};

Thursday, September 3, 2015

Eric Cheng's Cool Inspire Add-On

So Eric Cheng really is the coolest pilot in the world!  Look at the back of this Inspire, where he mounted a GoPro on a gimbal.  Eric writes:
DJI Inspire 1 flying aggressively at the beach with a Feiyu Tech FY-WG 3-Axis Wearable Gimbal for GoPro ( attached to the rear via curved GoPro mount. Shot with GoPro HERO4 Black. Footage taken during the documentary shoot with (Santa Cruz) Flight Club.

I might try this with my old no-name gimbal and see how it goes.

Eric mentions he got up to 55 MPH on this video.  Impressive!

blogodex = {"idx" : ["Inspire 1", "Gimbal", "Eric Cheng"]};

Tuesday, September 1, 2015

Modding an Apple Mac Power Supply, Part 2

 Now that we've got the Apple power supply running, we need to hook it up to the charger.  It turns out that standard 110V blades fit perfectly into the GND and 12V slots, so we just harvest a couple from an old wall wart.
Solder onto 12 gauge wire.  My charger has 4mm bullets, so I soldered that onto the other end of the wire.
 Shrink wrapped.  I measured how far the blades would go into the connector, and measured the shrink wrap accordingly.
 The fit is nice and tight.  I don't think it will slip out, but if it does that's safe since it will lose connection to the hot wires.
 I used a piece of bigger heat shrink to hold everything together.  Go onto ebay and you can buy a lifetime supply of various sized shrink tube for a couple of bucks. I think this was 10mm shrink tube.
 I tried fitting a switch in place of the paper clip.  I learned that you can't solder onto a paper clip!  The Internet reveals that they are typically plated with some sort of alloy (tin/nickel?) that isn't attractive to solder.

A couple of old male servo leads worked nicely, but was wobbly.  I might run this with a length of wire, and then attach the switch onto the charger.  Till then, it's a paperclip jammed into the connector, which somehow pleases me very much!

Out with the old, in with the new.  Goodbye old Dell power supply, and thanks for the years of faithful yet kinda ugly and a bit underpowered service you provided.

blogdex = {"toc" : "Power Supply"};

Sunday, August 30, 2015

Modding an Apple Mac Pro Power Supply

 I got an old Mac Pro power supply to replace my puny old Dell.  The thing is massive!  79A of 12V power, that's over 900 watts!!

But, there's a catch.  Like all things Apple, it's a beautifully crafted, high quality unit.  And unlike the rats-nest wiring associated with PC power supplies, it's got a single clean wiring harness which is sadly undocumented on the Internet.
 I guessed the large connectors would be for 12V and ground.  Measuring the voltages would indicate the polarity.  BUT  How to turn the unit on?  I was looking for the equivalent of the PC's Green PWR Wire, the one that if shorted out turns on the power supply.

Going strictly by guess, I started shorting out pairs of connections.  I figured it couldn't do much harm, since none of the wires would be carrying current if the PWR wire were not engaged.
Using a paper clip, I quickly found the pair of PWR,GND connection.  I'm not sure which one is which, but for my purposes it doesn't really matter.  I made a note of the connections so that I'll be able to recreate them when I cons up a connector to the charger.

The outside big connectors are both GND, and the inside big connectors are both +12.2V.  The PWR/GND pair is the outside small connectors, second from the bottom.  The connector is oriented so the left side is smooth, and the right side has the edge.
A slight bit of fiddling showed that the small curve of a paper clip was the perfect size to connect PWR/GND.  I snapped a picture of it and will cover it with tape to ensure it stays put.

That's it for the experiment phase.  I'll use the flat blades from an old extension cord to bodge up a connector for 4mm bullets which is what my power supply uses.  I'll update when I do that!

Here's a video walkthrough:

blogodex = {"toc" : "Power Supplies", "idx" : ["Mac", "charging", "power", "electronics"]};