Category: RC models

Trial of prototype stand alone GPS logger

An upcoming project calls for a stand alone GPS logger.

The requirement is for a GPS stream that allows correction using RTKLIB, but this trial is of a lesser GPS as proof of concept.

SAGPS001

Above, the equipment consists here of a Ublox NEO-6M based GPS module (~A$15 incl on eBay) at left, an Openlogger (~A$15 incl post on eBay) at right, and a 12V-5V converter (~A$7 from Hobbyking) at bottom. The latter is a 5A converter, way overkill, but it was on hand. The GPS module has a 3V regulator on board for the NEO-6M chip.
Continue reading Trial of prototype stand alone GPS logger

Last update: 28th November, 2015, 12:51 PM

The BLHeli sojourn is over

I was an early embracer of BLHeli ESC firmware on a Silabs based ESC, the Hobbywing Skywalker 40A UBEC.

Skywalker40A

The ESC looked to have quality hardware, and BLHeli was choice in aftermarket firmware.

The Skywalker did perform better with BLHeli than the stock firmware.

When BLHeli was released for the AVR based ESCs, I gave it a trial both on the bench in instrumented tests and in the air on a couple of quadcopters with different ESC / motor / prop / FC combinations.

I cannot say that BLHeli for AVR was any better than SimonK, and generally poorer though not much poorer.

More recently, users have reported some serious issues through BLHeli 14.0 and 14.1, and I removed the Skywalkers from service out of concern there were problems to be fixed. Continue reading The BLHeli sojourn is over

Last update: 28th November, 2015, 9:04 AM

NAZE32 / Cleanflight trial

Overview

The Naze32 is hardly new, but it does seem to have reached a maturity where it, alternative firmware and the support tools are functional and fairly stable.

The article describes a project to fit a Naze32 to an existing quadcopter that used a Multiwii flight controller on a Atmega 328P platform, and initial perceptions.

The 32bit processor at 72MHz provides a lot more computing power than the old 8bit processor at 16MHz.

Implementation

An early decision was made to try Cleanflight as first option, as it appears to work well, is responsive for user issues, has a good PC client and is configurable from Arduino using the EZ-GUI client that I use for Multiwii.

Naze32Above is the Naze32 undergoing Bluetooth testing before fitment to the quadcopter. Continue reading NAZE32 / Cleanflight trial

Last update: 17th October, 2015, 7:04 AM

DYS SN20A out of the box

I was intrigued by the seemingly endless stream of stories of woes with the DYS SN20A (eg RCTimer / DYS Mini SN20a / SN30a / SN40a esc), so I purchased one to see if they are all bad. Of course, impressions of a sample of size one are of somewhat limited value, but it seemed like an interesting thing to do.

Some reports of problems seem to relate to use of BLHeli on the ESCs, and it seems at least one beta release of BLHeli v14 had defects that resulted in serious damage in unprotected tests.

Discussion blames problems on front ends, flight controllers, wiring, motors, ESCs hardware, firmware, and bootloaders… but all these possible causes evident more so with this one ESC does not seem likely or logical. With the quest for more rapid FC loop response, there is a risk of instability and the drive may be working harder with oscillating demand, only logs from a flying craft will reveal what may be happening in that respect.

The test ESC

The DYS SN20A was purchased 14/06/2015 from RCTimer for about US$19 inc post. Not an inexpensive ESC by any means.

The DYS SN20A is described as an “opto” but I doubt it is optically coupled, it is probably just another instance of the fraud in terminology where opto refers to a BECless ESC. (If it were optically coupled, it would almost certainly not be a bidirectional servo interface and the SimonK bootloader would not work… but it did.)

SN20-01Above, the top view of an unwrapped SN20A. Continue reading DYS SN20A out of the box

Last update: 25th September, 2015, 4:33 PM

Report on Hobbyking 40A ESC 4A UBEC 9261000003 / BC3540-14 brushless drive #2

Report on Hobbyking 40A ESC 4A UBEC 9261000003 / BC3530-14 brushless drive reported a set of measurements on a test on elements of a drive system which is the basis for one of my flying quads.

This article reports some interesting characteristics derived from the measurements.

Test configuration:

  • Gemfan 11×4.7″ SF propeller;
  • BC3530-14 1000Kv motor;
  • Hobbyking 40A ESC 4A UBEC 9261000003 (BEMF caps removed);
  • SimonK commit 02bd8e4ca36a06722efe51bc7cd5130d72a184b8 bs.hex with 2000ns dead time; and
  • 4Ah 4S Lipo battery.

Keep in mind that the application for this drive is a multirotor, and hover speed is around 3800RPM, so efficiency in that region is critical to battery endurance. Continue reading Report on Hobbyking 40A ESC 4A UBEC 9261000003 / BC3540-14 brushless drive #2

Last update: 17th May, 2015, 9:42 AM

BLDC ESC – effect of insufficient dead time

This article reports measurements on a brushless drive used for an RC quadcopter.

Dead time is the time allowed between turning one FET in a half bridge off and the other FET on to ensure that they do not both conduct simultaneously, even for an instant, as very large currents may flow. The dead time specified in ESC configuation is an ‘additional’ delay added over and above circuit delays.

ESC02

Measuring a stable properly synchronised drive system at minimum speed can expose the effects of insufficient dead time on total drive input current. At minimum speed, very little power is delivered to the propeller and most drive input power is lost in various system losses, so drive current becomes very sensitive to system losses. Continue reading BLDC ESC – effect of insufficient dead time

Last update: 11th May, 2015, 9:24 AM

Report on Hobbyking 40A ESC 4A UBEC 9261000003 / BC3540-14 brushless drive

This article documents some a test on elements of a drive system which is the basis for one of my flying quads.

Test configuration:

  • Gemfan 11×4.7″ SF propeller;
  • BC3530-14 1000Kv motor;
  • Hobbyking 40A ESC 4A UBEC 9261000003 (BEMF caps removed);
  • SimonK commit 02bd8e4ca36a06722efe51bc7cd5130d72a184b8 bs.hex with 2000ns dead time; and
  • 4Ah 4S Lipo battery.

The dead time was chosen for compatibility with F-40A which I also use. Dead time of 1200ns is sufficient for the 9261000003.

This is quite a low cost drive, the 300W+ motor cost about A$14 and the 40/60A 6S ESC just under A$20 at the time of purchase.

The tests were conducted at 4S as a stress test (up to 170% of rated current), the quadcopter uses 3S. Continue reading Report on Hobbyking 40A ESC 4A UBEC 9261000003 / BC3540-14 brushless drive

Last update: 6th May, 2015, 5:36 PM

Hobbyking Swamp Dawg build – #1

SwampDawg01

I couldn’t resist the Hobbyking Swap Dawg as an opportunity to play with SimonK ESC firmware with forward / reverse enabled.

ESC selection and implementation

I selected a Hobbyking F-30A ESC, which might seem a bit of overkill but it is a closed air space which reduces its dissipation capacity. The F-30A have proven themselves reliable with SimonK on a range of BLDC motors. Continue reading Hobbyking Swamp Dawg build – #1

Last update: 16th March, 2015, 8:58 AM

SimonK on Hobbyking 40A ESC 4A UBEC 9261000003

Following on from BLHeli on Hobbyking 40A ESC 4A UBEC 9261000003 – #3, further tests were conducted on the ‘chugging’ ESC.

The 9261000003 is a relatively low cost ESC with 6S rating and fast FETs.

At Simon’s suggestion, the BEMF caps were removed. This eliminated the chugging effect on both the DT750 and 4822-690KV where it had been previously observed. The 4700pF BEMF caps are in a vertical row at the bottom right of the pic above.

I used to routinely remove BEMF caps (a carry over from using WiiEsc), but found on some tests that it made insignificant difference. That might be the case for some motors and smallish caps (1000pF), but in this case, the combination of these challenging motors and largish BEMF caps were incompatible and removing the caps solved the problem. Continue reading SimonK on Hobbyking 40A ESC 4A UBEC 9261000003

Last update: 13th December, 2016, 8:20 AM