Thursday, September 20, 2018

Shunda TEC-06 Battery Tester



Operation:

  • current used in AH.  Press to start Mode 1 testing.
  • battery voltage. No testing, current voltage.  Mode 1: open circuit voltage (no load). Mode 2: voltage under load.  Press to start Mode 2 testing.
  • final voltage.  Testing stops at this voltage.
  • discharge current in mA.  50-3500.
  • internal resistan in Ω. Reported in Mode 1 with 4-wire harness.

Best reference:
Reverse engineered serial protocol:

Wednesday, July 25, 2018

EastBay RC Guide to Sections 343 and 344.

Disclaimer: I am not a lawyer, etc.  Here's my layman's interpretation of sections 343 and 344 of this document: https://www.congress.gov/bill/115th-congress/house-bill/4/text.  Note that I'm not expressing any opinions, just trying to understand what the bill says.

The top part is my interpretation, followed by my interpretation inlined with original text. Did I come close to getting it right? Let me know what you think!


SEC. 343. SPECIAL RULES FOR MODEL AIRCRAFT.
FAA can't make rules regarding model aircraft. except as noted here.


FAA can require you to register and put your registration number on your aircraft.


FAA can make rules if you have an autopilot or BLOS (beyond line of sight) features and you meet these requirements: fly as a hobby, join a CBO, fly with their rules, less than 55 lbs, fly safely, don't fly over amusement parks, tell airport operators when you're flying nearby. See section 344 below if you don't meet these requirements.


When FAA has an "automated airspace authorization system" you have to use it, unless you're at an approved "permanent location".


CBO-sponsored educational stuff is simple model flying even if you're paid, e.g. sponsored pilots.

They can come after anyone endangering safety, no matter what.


CBOs are nonprofits who further model aviation, provide safety guidelines, support local clubs, and provide support for developing local flying sites.


FAA will publish recognition guidelines for CBOs.
This all becomes effective when the Act passes.


SEC. 344. RECREATIONAL UAS.
This if for everyone who doesn't meet the requirements in section 343 (above) or part 107 (which talks about commercial operations).  I think this is the section that will apply to non-AMA members.


Within 120 days, FAA will issue rules regarding this category of flying, as detailed below.
You have to take an online class.
It's OK if you're under 16.
When "automated airspace authorization system" is implemented, you have to use it.
FAA can't require special licensing, exams, certifications, etc.


---------------------------------------------------------------------------------------------------------


The following is the comments above, inlined with the text at https://www.congress.gov/bill/115th-congress/house-bill/4/text


SEC. 343. SPECIAL RULES FOR MODEL AIRCRAFT.
(a) In General.—Notwithstanding any other provision of law relating to the incorporation of unmanned aircraft systems into Federal Aviation Administration plans and policies, including this subtitle, the Administrator of the Federal Aviation Administration may not promulgate any rule or regulation regarding a model aircraft or an aircraft being developed as a model aircraft,


FAA can't make rules regarding model aircraft. Same as before, but with exceptions below.


except for—
(1) rules regarding the registration of certain model aircraft pursuant to section 44103; and


FAA can require you to register and put your registration number on your aircraft.


(2) rules regarding unmanned aircraft that by design provide advanced flight capabilities enabling active, sustained, and controlled navigation of the aircraft beyond the visual line of sight of the operator, if—
(A) the aircraft is flown strictly for hobby or recreational use;
(B) the model aircraft operator is a current member of a community-based organization and whose aircraft is operated in accordance with the organization’s safety rules;
(C) the aircraft is limited to not more than 55 pounds unless otherwise certified through a design, construction, inspection, flight test, and operational safety program administered by a community-based organization;
(D) the aircraft is operated in a manner that does not interfere with and gives way to any manned aircraft;
(E) the aircraft is not operated over or within the property of a fixed site facility that operates amusement rides available for use by the general public or the property extending 500 lateral feet beyond the perimeter of such facility unless the operation is authorized by the owner of the amusement facility; and
(F) when flown within 5 miles of an airport, the operator of the aircraft provides the airport operator and the airport air traffic control tower (when an air traffic facility is located at the airport) with prior notice of the operation (model aircraft operators flying from a permanent location within 5 miles of an airport should establish a mutually agreed upon operating procedure with the airport operator and the airport air traffic control tower (when an air traffic facility is located at the airport)).
FAA can make rules if you have an autopilot or BLOS features and you meet these requirements: fly as a hobby, join a CBO, fly with their rules, less than 55 lbs, fly safely, don't fly over amusement parks, tell airport operators when you're flying nearby. See next section if you don't meet these requirements.


(b) Automated Instant Authorization.—When the FAA has developed and implemented an automated airspace authorization system for the airspace in which the operator wants to operate, the model aircraft operator shall use this system for authorization to controlled airspace unless flown—
(1) at a permanent location agreed to by the Administrator; and
(2) in accordance with a mutually agreed upon operating procedure established with the airport operator and the airport air traffic control tower (when an air traffic facility is located at the airport).


When they have an "automated airspace authorization system" you have to use it, unless you're at an approved "permanent location".


(d) Commercial Operation For Instructional Or Educational Purposes.—A flight of an unmanned aircraft shall be treated as a flight of a model aircraft for purposes of subsection (a) (regardless of any compensation, reimbursement, or other consideration exchanged or incidental economic benefit gained in the course of planning, operating, or supervising the flight), if the flight is—
(1) conducted for instructional or educational purposes; and
(2) operated or supervised by a member of a community-based organization recognized pursuant to subsection (e).


CBO-sponsored educational stuff is simple model flying even if you're paid, e.g. sponsored pilots.


(e) Statutory Construction.—Nothing in this section may be construed to limit the authority of the Administrator to pursue enforcement action against persons operating model aircraft who endanger the safety of the national airspace system.


They can come after anyone endangering safety, no matter what.


(f) Community-Based Organization Defined.—In this section, the term “community-based organization” means a nationwide membership-based association entity that—
(1) is described in section 501(c)(3) of the Internal Revenue Code of 1986;
(2) is exempt from tax under section 501(a) of the Internal Revenue Code of 1986;
(3) the mission of which is demonstrably the furtherance of model aviation;
(4) provides a comprehensive set of safety guidelines for all aspects of model aviation addressing the assembly and operation of model aircraft and that emphasize safe aeromodeling operations within the national airspace system and the protection and safety of individuals and property on the ground, and may provide a comprehensive set of safety rules and programming for the operation of unmanned aircraft that have the advanced flight capabilities enabling active, sustained, and controlled navigation of the aircraft beyond visual line of sight of the operator;
(5) provides programming and support for any local charter organizations, affiliates, or clubs; and
(6) provides assistance and support in the development and operation of locally designated model aircraft flying sites.


CBOs are nonprofits who further model aviation, provide safety guidelines, support local clubs, and provide support for developing local flying sites.


(g) Recognition Of Community-Based Organizations.—In collaboration with aeromodelling stakeholders, the Administrator shall publish an advisory circular within 180 days of enactment that identifies the criteria and process required for recognition of nationwide community-based organizations. This recognition shall be in the form of a memorandum of agreement between the FAA and each community-based organization and does not require regulatory action to implement.


FAA will publish recognition guidelines for CBOs.


(h) Effective Date.—Except for rules to implement remote identification for unmanned aircraft that by design provide advanced flight capabilities enabling active, sustained, and controlled navigation of the aircraft beyond the visual line of sight of the operator and for rules regarding the registration of certain model aircraft pursuant to section 44103, this section shall become effective when the rule, referred to in section 532 of the FAA Reauthorization Act of 2018, regarding revisions to part 107 of title 14, Code of Federal Regulations, becomes final.


This all becomes effective when the Act passes.


SEC. 344. RECREATIONAL UAS.
(a) In General .—Not later than 120 days after the date of enactment of this Act, the Administrator of the Federal Aviation Administration shall issue rules and regulations relating to small UAS flown for recreational or educational use, and that are not operated within all of the criteria outlined in the special rule for model aircraft in section 45505 of title 49, United States Code, or the requirements of part 107 of title 14, Code of Federal Regulations.


This if for everyone who doesn't meet the requirements in section 343 (above) or part 107 (which talks about commercial operations).  I think this is the section that will apply to non-AMA members.


Within 120 days, FAA will issue rules regarding this category of flying, as detailed below.


(b) Regulatory Authority.—When issuing the rules and regulation pursuant to this section, the Administrator shall—
(1) require the completion of an online or electronic educational tutorial that is focused on knowledge of the primary rules necessary for the safe operation of such UAS and whose completion time is of reasonable length and limited duration;


You have to take an online class.


(2) include provisions that enable the operation of such UAS by individuals under the age of 16 without a certificated pilot;


It's OK if you're under 16.


(3) require UAS operators within Class B, C, D and E airspace to obtain authorization, as the Administrator may determine to be necessary within that airspace, but only after the Federal Aviation Administration has developed and implemented an automated airspace authorization system for the airspace in which the operator wants to operate; and
(4) include provisions that provide specific operational rules for UAS operating in close proximity to airports in class G airspace.


After the "automated airspace authorization system" is implemented, you have to use it.


(c) Maintaining Broad Access To UAS Technology.—When issuing rules or regulations for the operation of UAS under this section, the Administrator shall not—
(1) require the pilot or operator of the UAS to obtain or hold an airman certificate;
(2) require a practical flight examination, medical examination, or the completion of a flight training program;
(3) limit such UAS operations to pre-designated fixed locations or uncontrolled airspace; or
(4) require airworthiness certification of any UAS operated pursuant to this section.


FAA can't require special licensing, exams, certifications, etc.


(d) Collaboration.—The Administrator shall carry out this section in collaboration with industry and community-based organizations.


----------------------------------------

Tuesday, April 24, 2018

Stepper Motor: Microstepping

A coworker explains it to me:
TL;DR; is that instead of just having full forward/reverse current or not on each winding, the driver can also do things like 90%/10%, 80%/20%, 70/30, etc. current for the two windings to position the motors at angles between the full/half step positions. the actual ratios aren't quite this simplistic, and are designed to achieve something close to constant holding torque and even step spacing, but since the exact angle achieved for any winding current ratio depends on the motor design, and application, it's more or less impossible to get microstep positions that are a precise fraction of the full step angle for all motors/applications. this is mostly OK because 1) you're not making the full step positions any less accurate, 2) you're still making motor motion smoother by taking smaller steps.
a longer explanation can be found at https://hackaday.com/2016/08/29/how-accurate-is-microstepping-really/. if you want to go deeper that that, there are lots of motor controller app notes out there with all the gorey engineering details.

blogodex = {"idx" : ["electronics", "stepper motors", "microstepping"]};

Tuesday, November 14, 2017

Donkey Cars!

Chris Anderson started DIY Robocars, and Adam Conway and William Roscoe's response is the Donkey Car.  And EastBay RC is building two of them!

http://www.donkeycar.com
Build Guide

blogodex = {"toc": "Donkey Car"};

Tuesday, September 19, 2017

TurboParker's Guide to UMX Radian Trimming

Copied from RCGroups:

Initial balancing & trimming:

1) MEASURE the CG on your plane. Do whatever is necessary to adjust it to 31mm, which is the factory recommended starting point. Do this before you try anything else.

2) Zero your tx trims. If your transmitter allows, adjust the trim-steps to the smallest setting. (Usually "1".)

3) Power-up the plane, but do not engage AS3X. Then disconnect the battery.

4) Mechanically trim the elevator so that it's neutral with respect to the stab.

5) Take the plane up for a flight with the CG @ 31mm & see how it behaves power-off & power-on.

6) If it glides smoothly & doesn't balloon under power, you're done.

7) If it porpoises during the glide and/or balloons under power - add down-trim until it glides smoothly, then zero your tx trim & transfer the tx trim to mechanical trim.

8) Note the degrees of down-trim with respect to the stab. If it's only a few degrees or so, you can call it good - unless you're trying to squeeze every last bit of glide performance out of the airframe that you can get. If you're trying to set a personal UMXR glide record, adjust the decalage accordingly, so that no visible trim is needed for best glide with the CG at 31-32mm. If the plane needs a lot of visible down-trim with the CG at 31-32mm, the decalage is off enough to warrant fixing it or returning the plane & getting a replacement.

Remember that you must re-trim the elevator for best glide whenever you change the CG. That is absolutely mandatory. If you don't, you will simply end up chasing your tail & get frustrated with the process of flight-trimming. When you get it right, you will be rewarded with a plane that glides smoothly & efficiently, and exhibits very little (if any) throttle-pitch coupling under power. See the video below for an example of how the plane is supposed to behave when it's trimmed & balanced correctly, and the decalage is about right. Be sure to turn up the sound, as I narrate during the flight. It's a bit long, but the 19 minutes it takes to watch the entire video will most likely be worth it for those who are new to sailplanes.

Here's another method of fine-tuning the CG:

1) Take the plane up high, trim for level flight @ say 20-25% throttle. Better yet, trim for the flattest stable power-off glide (no porpoising).

2) Enter a power-off dive at a 45-degree angle, then release the sticks, and observe the plane's behavior:

A. Plane pulls sharply out of the dive as soon as you release the elevator: The plane is extremely nose-heavy. Move the CG aft, take the plane back up, re-trim as described above, then repeat the test.

B. Plane starts to dive more steeply (tucks toward the belly) when you release the elevator: The plane is tail-heavy. Move the CG forward, take the plane up, re-trim as described above, then repeat the test.

C. Plane continues on its path: The CG is at the neutral-handling point (often called the sweet-spot), which provides the greatest sensitivity to lift (the plane will indicate weaker lift than it will when it's nose-heavy). A neutral CG also results in the lowest stall-speed & the least amount of drag. But it also makes the plane neutrally-stable in pitch, so it will not self-correct in a dive. Many competition sailplane pilots prefer a neutral CG, but some pilots prefer a slightly-forward CG.

D. Plane starts to gently pull out of the dive when you release the stick: The CG is just slightly forward of neutral. The plane will still indicate light lift (albeit not quite as well as it would with a neutral CG), and it will be more stable in pitch than it is with a neutral CG. Some sailplane pilots prefer this CG position, as the slightly positive pitch-stability makes the plane less-apt to suddenly enter a dive or climb on its own when it gets perturbed by the air currents. The slight loss of efficiency is rarely noticeable to casual sailplane pilots who are not concerned with getting every last bit of performance from the airframe.

Remember that at this scale, moving the CG just 1-2mm is noticeable in flight. Avoid making large changes unless you're sure that the the CG is way off. Also, remember to re-trim for level flight each time you move the CG. This is absolutely critical. Failure to re-trim as described above will negate the entire process.

Also remember that CG is not a fixed number. Move it forward a bit for better wind-penetration on turbulent days, or for increased glide speed on windy days. Move it back to the sweet-spot in calm conditions and/or when lift is very light & you want to stay aloft on the farts of field-mice alone.

If the decalage is correct, you'll end up with the elevator level or close to level with respect to the stab after the above tests. If not - then the decalage is likely off. Which means you'd need to do the decalage test.

Decalage test:

1) Zero your elevator trim on the tx, then mechanically neutralize the elevator with respect to the stab.

2) Take the plane up, but do not re-trim the elevator in flight. This is absolutely critical, as re-trimming the elevator after neutralizing it before the flight will screw up the test & render the results useless.

3) Perform a power-off vertical dive from high altitude, release the elevator stick, and observe the plane's behavior:

A. Model continues straight down: No change needed.

B. Model pulls to canopy: Increase stab incidence with respect to the wing.

C. Model pulls to belly: Reduce stab incidence with respect to the wing.

Adjusting the CG as described above is the next step after verifying that the decalage is correct.

Here's where the batt ends up on mine to get the CG to the sweet-spot for best glide performance & power-on behavior. You can also see the CG 'sweet-spot' marks on the wings:


TurboParker's Narrated Video:


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

Sunday, September 17, 2017

NutBall Aerobatics

GoldGuy, the inventor of the NutBall, reveals some NutBall tricks and his propensity for poetry:

1.  Next time your out, experience the distinctive sound made by a NutBall. Here's how............

Take it to altitude with the nose up, instantly give it full down and full left. It will flip over and go into a violent but controllable spin. Hear that sound it makes? It's the only model I know that does it. To slow down it's decent, just cut the throttle. To get out of it, just relax the controls, then feed in a bit of up. Cool eh?

2.  The snap roll is similar. Flying straight and level fed in some up and then do the same, down and left. If you time it right, you'll get one complete violent snap in an instant. Practice at altitude and when you get it right, do it at eye level for best effect and you'll come out looking like a pro.

Also, in that inverted flat spin mode you can use the throttle and elevator to go up and down. Hold in the rudder the whole time..................throttle back, it will come down, add throttle and a bit more down and it will go up. You can go up and down in that inverted spinning mode as long as you wish.

You will have to move the battery back for a 30 to 35% CG for best flopabatics.

3.  Rolling the NutBall is an easy to do and a basic maneuver. Once you've mastered it, the roll becomes the basis for the snap roll, spins, inverted flat spin (complete with sound effects), the inverted 'elevator', both up and down, plus other silly weird stuff.

Rolling is more than just slapping over the rudder stick with the NB, although with models like the Simple Delta, flat and with elevons, that's all it takes to look good. What you want is to practice nice smooth rolls where the speed of rotation is the same throughout the 360 degrees of travel, it can be done almost axel, it's all in the timing and rolling to the left is easier to start off with. Make sure you set the CG at 25 percent to start, you can modify that as you progress, fly the maneuver at a MEDIUM speed at first and pay attention to the amount of movement on the rudder and elevator, not too much (???) is lots. The big problem in rolling the NutBall is that with too much rudder throw it wants to flip over very quickly once past inverted. How much movement is all apart of fine tuning. Having a low wing loading is a big aid in flying aerobatics as everything is much easier to do. If there's too much of a breeze, mount a bigger battery or some lead ballast, keeping the CG unchanged.

So, here's what to do to start off with.....................

Fly along straight and level at a brisk speed, but not full tilt (yet), and just before you enter the roll, add a tiny bit of up elevator to rise the nose, then feed in the rudder nice and smooth and when it goes inverted give it a tiny blip of down elevator and let off on the rudder just after is goes past inverted. What you need to do in the beginning is to form a pattern or tune in your brain. Practice in your shop with the model in front of you, try and picture in your mind what's happening. I learned four point rolls by repeating this to myself as I moved the sticks in the proper sequence and at the proper speed................ta da, ta da, ta da, ta da. It's like a tune in your head and you keep to the timing. Not sure what key I'm in, but it works. Got that from the best 3D pilot I know.

When you go out to practice, by yourself seems best and concertrate on the one thing and do just that.

#4 Here's another easy fun one anyone can do, the 'upright elevator', although it's all down elevator, no up. You'll need a rearward CG for this one, but start off with what you've got to see the difference it makes. Gain lots of altitude and point the nose straight into the wind. Now, hit full up and hold, and kill the thottle at the same time (again, it's in the timing) and use just the rudder to keep it facing into the wind. It should float down like a leaf, and with a low wing loading and a nice breeze you can plop it right down on the wheels. You can do this one inverted too.

Have fun with it.............all it takes is a bit of practice and a little more after that............your starting to look like a pro now...............keep it up



Most aerobatics it will do
And referring to how it flew,
If someone shouts, "a NutBall, WOW"
I wouldn't bother takin' a bow,
Cause they're probably talkin' about YOU

Wednesday, September 6, 2017

2017 Shopping List

Here's what you need to get started in Remote Control Aeromodelling!  This is everything you need except for actual aircraft.


Transmitter and Battery (one each)

https://alofthobbies.com/frsky-taranis-q-x7.html
https://alofthobbies.com/72v-2600-aa-nimh-qx7-transmitter-pack.html


4-Channel Receiver and Voltage Sensor (one each, for each model)

https://alofthobbies.com/frsky-d4r-ii-4-8-channel-receiver-with-27ms-cppm.html
https://alofthobbies.com/frsky-battery-voltage-sensor-fbvs-01.html


8-Channel Receiver (if you need more than 4 channels)

Get one of these instead of the 4-channel if your model needs more than 4 channels.

https://alofthobbies.com/frsky-d8r-ii-plus-8-channel-receiver.html


OrangeRX DSM2/DSMX transmitter module

If you want to fly a plane that uses a Spektrum DSM2/DSMX compatible receiver

https://hobbyking.com/en_us/orangerx-dsmx-dsm2-compatible-2-4ghz-transmitter-module-v1-2.html


Battery Charger and Accessories

Charger:
https://hobbyking.com/en_us/turnigy-accucel-6-80w-10a-balancer-charger-lihv-capable.html

Charging Cables:
https://hobbyking.com/en_us/multi-function-charge-lead-with-4mm-banana-plugs.html


Power Supply

The above Charger doesn't include a power supply.  You can use an old PC power supply or laptop power supply if you've got one.  If not, this one will do what you need.

https://hobbyking.com/en_us/t240-power-supply.html


Monday, July 17, 2017

Revo IR Meter


http://www.store.revolectrix.com/Products/Accessories/DCIR-Meter


- Supports up to 6S LiPO battery packs
- DC IR measurements up to 2 decimal places (cell & pack)
- Independent pack voltage measurement capability
- Large built in LCD
- XT60 Input
- Single balance connector able to run 2S - 6S packs

Perfect battery checker to test your packs true capability.
Videos on how to use The Honesty Meter at: https://www.youtube.com/channel/UCZDTf30EKTuZcEfbWlElitg

Dimensions: 11cmL x 8cmW x 6cmH.

Weight: .3 kg
Will be available mid June
Price: $69.95 (Excl. GST)

Tuesday, February 28, 2017

Monoprice MP Select Mini Notes



Got my Select Mini running, here's some notes.

My Simple Guide

  • Everything pretty much worked out of the box.  Don't need to start modding right away.
  • Print the cat model on the supplied SD card.  Should work well.
  • My SD card was a bit sketchy.  Sometimes the printer couldn't read it.  I replaced it with another SD card.
  • The Monoprice links were terrible for Mac.  I set everything up as per the next section.
  • Sometimes the power supply is bit sketchy.

My Mac Configuration

Install Cura, and add Bob's files to the appropriate places in /Applications/Cura.  You should see the Mini as a printer option in Cura, with 100 micron and 200 micron configurations.

Update: Cura 2.4

Install Cura 2.4 and before running:

cp github/mp_select_mini/resources/definitions/mp_select_mini.def.json /Applications/Cura240.app/Contents/Resources/resources/definitions

Bob uses 220 degrees, 210 works well with my setup.

PrintRun

Control your printer with a computer GUI.  Cross platform.

https://github.com/kliment/Printrun

OpenSCAD

http://www.openscad.org/
http://www.openscad.org/cheatsheet/
https://www.thingiverse.com/jumpstart/openscad



Resources

http://malyansys.com/en/?page_id=315
http://wiki.malyansys.com/doku.php?id=firmware_update_procedure&rev=1465820046
http://mpselectmini.com/start
https://docs.google.com/document/d/1HJaLIcUD4oiIUYu6In7Bxf7WxAOiT3n48RvOe5pvSHk/edit#

GCode

http://reprap.org/wiki/G-code
http://mpselectmini.com/extended_g-code_table



Reviews

http://hackaday.com/2016/06/13/review-monoprice-mp-select-mini-3d-printer
http://johnbiehler.com/2016/06/05/monoprice-maker-select-mini-3d-printer
https://all3dp.com/monoprice-mp-select-mini-3d-printer-review
http://www.thetylergibson.com/3d-printing-for-the-absolute-beginner-monoprice-select-mini-2


Groups
https://www.reddit.com/r/MPSelectMiniOwners/


Mods

http://www.thetylergibson.com/monoprice-select-mini-part-2-flashing-the-firmware
http://www.thetylergibson.com/monoprice-select-mini-part-3-tuning-and-slicing
https://hackaday.io/project/12184-monoprice-mp-select-mini-e3d-hotend-adapter

Related

http://octoprint.org
http://www.protoparadigm.com/
http://kliment.kapsi.fi/printrun/

PID Settings

# set printhead pids
M301 P36.00 I0.012 D72.00 C0.12 L2
# set bed pids
M304 P106.56 I0.024 D96.81
# write parms
M500
# print parms
M503

Setting WiFi

M550 SSID

M551 PASSWORD


Interesting GCode

G28         ; home
M190 S60    ; Wait for bed temperature to reach target temp
M104 S195   ; Set Extruder Temperature target and continue
M109 S195   ; Set Extruder Temperature and Wait


Some snippets for init/deinit

Start:
----------------------------------------------------------------
G28 ;Home
G1 Z15.0 F6000 ;Move the platform down 15mm
;Prime the extruder
G92 E0
G1 F200 E3
G92 E0
----------------------------------------------------------------


End:
---------------------------------------------------------------
M104 S0
M140 S0
;Retract the filament
G92 E1
G1 E-1 F300
G28 X0 Y0
M84
----------------------------------------------------------------

blogodex = {"toc" : "MP Select Mini", "idx : ["3D Printing", "Printing Setup"]};

Saturday, November 5, 2016

Notes on Attacking DSMx with SDR

Here's the original article:
http://arstechnica.com/security/2016/10/drone-hijacker-gives-hackers-complete-control-of-aircraft-in-midflight/

The speaker's notes from the presentation:
https://prezi.com/vh4in2krlaoh/attacking-dsmx-with-sdr-pacsec-2016-english/#

An upcoming course:
https://www.cansecwest.com/dojos/2016/radio_reverse.html

And where he sourced his equipment:
https://1bitsquared.com/

Ernst Rudders for HobbyKing Tundra

Saw this on RCGroups. This seems a better solution than the stock rudder mount.  gravity keeps the Ernst rudders down and will kick up as necessary.  I'm not sure of the exact size.  Note the pull-pull mechanism connecting to the single servo.





Here's a picture of another plane with the rudders mounted on wood at the back.









Part description is:
Water Rudder .40-.60
ERNST MANUFACTURING INC. ERN155

https://www.hobbyzone.com/ernst/ERN155.html





blogodex = {"toc" : "Tundra", "idx" : ["Ernst", "floats", "rudder", "water rudder"]};

Friday, September 2, 2016

Links for Wayne Giles ESR Meter

Wayne is shutting down production himself as he moves on in retirement; I hope somebody picks it up!

Thanks Wayne, and hope you enjoy your retirement!





Here's some random links for posterity.

RCGroups Thread on V2 unit
RCGroups Thread on V1 unit
Unit at Progressive RC
Proof C Ratings are Useless  -- very true!










Four-Wire (Kelvin) Resistance Measurements

Due to the limitations of the two-wire method, the four-wire (Kelvin) connection method shown in Figure 2 is generallypreferred for low resistance measurements because it reduces the effect of test lead resistance. These measurements can be made using a DMM, SourceMeter SMU instrument, or a separate current source and voltmeter. With this configuration, the test current (I) is forced through the test resistance (R) via one set of test leads, while the voltage (VM) across the DUT is measured through a second set of leads (sense leads). Although some small current (typically less than 100pA) may flow through the sense leads, it is usually negligible and can generally be ignored for all practical purposes. The voltage drop across the sense leads is negligible, so the voltage measured by the meter (VM) is essentially the same as the voltage (VR) across the resistance (R). As a result, the resistance value can be determined much more accurately than with the two-wire method.

Note that the voltage-sensing leads should be connected as close to the resistor under test as possible to avoid including part of the resistance of the test leads in the measurement.

and another Explanation of 4 Wire Kelvin Testing.

This video covers the V1 unit:





blogodex = {"toc" : "ESR Meter", "idx" = ["Wayne Giles", "power", "batteries"]};

RC Receiver USB Adaptor

An interesting project from gregnau @ rcgroups:
http://www.rcgroups.com/forums/showthread.php?t=2714430

gregnau writes:

RC Receiver USB Adapter

Arduino based game controller adapter for regular RC receivers up to 6 channels.
It acts as an USB joystick, dispatching the channels values read from a PWM RC receiver. Aimed to be fast and responsible, though simple to use with automatic calibration function. It can be useful to play simulator wireless from the computer with your favourite transmitter. Compatible withWindowsMacLinuxAndroid,IOS.

Parts-list

Requirements
The .hex file and the supplied installer is only compatible with Sparkfun Pro Micro, do not try to flash it on other Arduino compatible devices. If you want to give it a go on other boards, then compile from source! Source:http://github.com/gregnau/wireless_rc_adapter
Installer should be easy as double-clicking the install.bat while the Pro Micro is plugged in. Everything is detailed to the screen, so if there is any error you can start investigating 

Worth checking before flashing!
hex-file checksum: d7065aed90c259e7ef3d8fe3dad3f1d7

Some jumperwires are needed to connect the receiver to the Pro Micro. Below on the picture you can see an example of wiring and setup in details.

Wiring
(it is attached below to the post, i have no idea how to put it here)
wiring.png

Manual
The Pro Micro boards usually have 2 leds side-by-side, which are the TX and RX status lights. These are used to reflect the state of the adapter:
On every startup these are flashing twice, then one of them is going off, the other one stays on. This means booted up successfully and ready to play.
But if they stay on, that means the adapter is in calibration mode. The calibration data is loaded and verified during setup,
but if these are incorrect/missing than it goes to calibration mode automatically.
Automatic calibration
Calibration process is the same as everywhere, the sticks, pots, switches on all channels must moved to their extents. Preferably more than once and in slow motion.
The leds are lit
During calibration there is no sending of joystick values to the host, there is no feedback at all, except it is in '#DEBUG_ENABLED' mode. Though in debug mode it's only using terminal to send data, there is no hid interface. While in normal operation after the calibration data is accepted and saved it goes directly to play mode. 
Manual calibration
Sometimes it is needed to re-calibrate the adapter, although there is valid calibration data saved. To achieve that just plug in the usb while pushing the attached button. Then everything should be the same as with automatic process.
---
> Still under development so any advice is welcome regarding the code or feedback on use! Only known restriction is the calibration autosave function accepts only if there is 6 working channels calibrated. In case you connect less channels then you always need to push the button to save calibration data.

blogodex = {"idx" : "radio"}