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Member postings for Mike Blandford

Here is a list of all the postings Mike Blandford has made in our forums. Click on a thread name to jump to the thread.

Thread: FrSky Major Update for most TX and RX
17/01/2020 22:56:50

The update from FrSky,, which this thread is really about, only affects the RF modules and receivers.
I've updated a Taranis plus internal module and a X8R for testing (and reverse engineering). The updated module still binds to a "D8" receiver (in D8 mode). In D16 (X) mode, the module and receiver will only bind to each other.

The X8R will not bind in D8 mode, even though linking channels 7&8 and powering it on does start it in bind mode.

If you update a module, it will only bind to an updated receiver, and vice versa.

The multi-protocol module will not bind to an updated receiver (yet!).

Mike

16/01/2020 19:06:51

Note that if you update a receiver then you won't be able to use a multi-protocol module (MPM) with that receiver as the MPM doesn't support this revised protocol (yet).

Mike

Thread: battery c rating
14/01/2020 16:56:53

My understanding is that lithium batteries degrade over time, regardless of whether they are being used or not. This results in the internal resistance increasing. Since a higher "c" rated battery starts with a lower value of internal resistance, it is likely to be longer before it becomes too high for the battery to perform well.

I also understand that this ageing process may be reduced by storing the batteries at a lower temperature.

Mike

Thread: ESC overheating.
09/01/2020 00:02:48

The MOSFETs in ESCs do have a maximum voltage rating, so ESCs are rated by voltage as well as current.

The whole operation of a brushless ESC is very complex. The motor windings act as an inductor, so when the ESC switches the current off, the inductance creates a "back e.m.f." (separate from the e.m.f. generated due to rotation). With brushed motors, this caused current to continue to flow and needed a "catch diode" to prevent a very high voltage spike from occurring. Brushless ESCs also need catch diodes, but these are built into the MOSFETs. One disadvantage is the voltage drop across these diodes is around 0.6V, and with a significant current flowing there is a noticeable heating effect. Some ESCs may avoid this by switching the MOSFET on to short out the diode, but this has to be done very carefully or the battery is shorted out by having the "wrong" two MOSFETs on at the same time.

It is also important to have some cooling for the ESC. I recently started using a FrSky Neuron ESC. This includes full telemetry including the ESC temperature. While the installation should have provided some cooling flow, it clearly didn't work very well, the ESC temperature kept going up through a flight, and I've seen it as high as 77 degrees C. I added a small air scoop to direct air in to the ESC, now it doesn't go above 31 degrees C.

Mike

Thread: Jumper 4in1 module problem
05/01/2020 15:19:57

You should find that if you plug the USB into your PC, the module appears as a serial port.

Mike

Thread: FrSky Taranis - user chat
05/01/2020 12:38:00

Should work fine.

Mike

Thread: Hobby Porter
03/01/2020 16:06:13

Interesting, but they should really go for D16 (XJT type) protocol as D8 protocol is not legal in Europe for new transmitters. This also doesn't have any telemetry apparently, so that limits its use to my mind.

Mike

Thread: CAA announce New drone trials !
27/12/2019 15:05:54
Posted by Martin_K on 26/12/2019 22:24:39:

The FAA have released their anticipated Notice of Proposed Rulemaking for Remote Identification. This is in America and not the final document. I mention it here to reinforce the fact that preparations for commercial BVLOS are advancing.

When we get the equivalent European draft laws I expect those of us with the inclination will discuss it in The Gov't, BMFA & UAV legislation thread.

What I found interesting in something I read on this linked from another forum is it includes:

" including the small UAS rule, which covers drones weighing less than 55 pounds other than model aircraft "

so it looks like they may be EXCLUDING model aircraft.

Mike

Thread: Greetings from the land of Oz
24/12/2019 13:22:28

You might have a look at the open source firmware used on many radios er9x/erskyTx and openTx.

er9x, in particular, runs on AVR processors.

Mike

Thread: D8R-11 plus Receiver and EU LBT firmware
23/12/2019 23:24:11

In each of the .zip files is a single .bin file. You don't need to open it, just flash it to the receiver.

Have you downloaded the STM software that does the flashing?

Mike

Thread: FrSky Neuron ESC
22/12/2019 16:02:18

Try changing the initial value of "selected here (first part of line only shown):

local sensor = {sensorType = {selected = 13, list = {'Vario', 'FAS-40S'

The is an update to the SxR firmware that does let it configure external sensors. Because it has internal values you may change using SPort commands earlier firmware versions didn't allow any commands out on the SPort, they were all intercepted by the SxR.

I wonder if the Neuron is responding to TWO different physical IDs? As an ESC it uses an appID of 0xB50 (I suggested in the above change) while as a SBEC device it uses an appID of 0xE50.

You could try changing the B50 to E50 in the change I suggested and see if you get a different physical ID, maybe the same one as the FrSky LUA.

Mike

Thread: D8R-11 plus Receiver and EU LBT firmware
22/12/2019 12:29:13

Yes, this firmware makes a D8 receiver (almost) into a 'X' receiver.

Mike

Thread: FrSky Neuron ESC
22/12/2019 12:25:50

No it doesn't, needs another update.

You could try editing it in this area, where I've added data for the Neuron, it might work:

local sensorIdTx = 0x17 -- sensorid 18
local sensor = {sensorType = {selected = 12, list = {'Vario', 'FAS-40S', 'FLVSS', 'RPM', 'Fuel', 'Accel', 'GPS', 'Air speed', 'R Bus', 'Gas suit', 'X8R2ANA', 'Neuron', '-'}, dataId = { 0x100, 0x200, 0x300, 0x500, 0x600, 0x700, 0x800, 0xA00, 0xB00, 0xD00, 0xF103, 0xB50 }, elements = 12 },
sensorId = {selected = 29, elements = 28}}
local selection = {selected = 1, state = false, list = {'sensorType', 'sensorId'}, elements = 2}

Note the change to the value of "sensorIdTx " as well, I think this may have been translated from my original Basic script incorrectly.

Mike

22/12/2019 10:12:10

If you use the erskyTx bootloader, you get an option to "run an app". One of the apps available is a "change ID" app that lets you change the SPort ID of sensors to any valid value.

Mike

Thread: D8R-11 plus Receiver and EU LBT firmware
21/12/2019 23:51:45

On the link above, I've now posted an update to my D16 firmware for D8 receivers.

1. I now include a bootloader so after flashing this new version you no longer need to short the 2 pads to be able to flash any later versions.

2. By default the servo output pulses are at an18mS period. There is now an option to enable a 9mS period, with each channel individually configurable to 18 or 9mS. This is set by using a script on the Tx. I've included a script for erskyTx, which would need to be translated to LUA for openTx.

3. After some testing I've found the performance seems to be better if the "Auto tune" option is not used (so use a zero value as used by FrSky firmware). This is now the default, but "Auto tune" my be turned on.

4. I've removed the option to use the Tx signal as SBUS, as doing so makes it impossible to use any external sensors. However, the Tx signal, with the addition of a diode ecternally, my be used to provide a SPort compatible connection to use SPort sensors.

5. Tuning, SPort or hub, SBUS on chan 8, and SBUS on chan 4 are selectable using links at bind time.

6. Outputs of 1-8 or 9-16 are selectable at bind time via radio firmware.

I'm looking into adding an option to allow full mapping of the servo outputs. This would allow any channel to be placed on any servo output (it would also map the SBUS values at the same time).

Mike

Thread: Judder on all servos with DFT module
11/12/2019 00:50:20

In D8 mode, the module sends all 8 channels at a 9mS period, but every fourth 9mS period it doesn't send anything, instead this time is used by a telemetry receiver to send the telemetry data back to the Tx.

In PPM mode, the module has to measure each PPM pulse, and then it is sent in a digital format. The receiver (I believe) synchronises to the 9mS period and sends the servo pulses out every 18mS.

I just tried a DJT module (same hardware and firmware as the DFT) in a 9X with a SKY board upgrade, to a D8R-IIplus. The protocol to the DJT is PPM, and I can change the frame rate (erskyTx firmware on the Tx). I increased the frame period to 31mS, and I couldn't detect any significant stepping of a servo. Just possibly, the servos were slightly smoother when I reduced the frame period to 18mS.

This Tx creates the PPM frame by measuring the stick positions, then storing all the required pulse widths ready for transmission shortly before the start of the first PPM pulse.

I then swapped in a XJT module, configured for D8 mode, but using the PXX protocol. This sends the data to the module every 9mS in digital format. A servo was definitely smoother (I was using an old Hitec HS-303 with a 1 foot long balsa stick on it).

I would agree that any stepping being seen is due to phasing between the different frame rates, causing a significant variation in latency from stick movement to servo output pulse.. The more channels a Tx is sending, then the longer the frame period will be.

Mike

09/12/2019 18:53:46

You don't mention what transmitter you are using.
You say the servos judder. What do you mean by this? Do they move in response to the sticks, but don't stay still in any position?

If your Tx has a protocol setting, the DFT module requires PPM (not PCM).

Mike

Thread: Unexpected behaviour of SwE in Taranis
06/12/2019 11:54:08

CH8: MAX Weight(+100%) Switch(!SE^)

Does what you require.

Mike

Thread: Horus X10 Express
28/11/2019 23:13:04

You only need to do the self check and servo calibration once, so you don't need it permanently available.

How have you set switch G to control channel 12? I don't know FrOs, but I do have a X10 Express with FrOs currently on it (I needed it to test the PARA trainer function to the new X9LiteS running ersktTx, so FrSky sent me one!). I will be porting erskyTx to it when I have time.

So, I have an input map setting where FLP3 is set to SWG. I also have a channel set, in the output map, to use FLP3.
Then I've set another input AUX1 to be LSW2, but I (deliberately) don't have anything set on LSW2.
Finally, I have an EX-MIXER configured:
To: FLP3
Method as ":=" (replace)
SW: SWH_UP

This seems to work to prevent switch G from controlling the channel unless switch H is pulled.

There may be a better way, but I haven't investigated FrOs further to find one!

Mike

Thread: FrSky Neuron ESC
26/11/2019 12:43:04

What update download is this in? I can't locate one on the FrSky site with such a LUA script in it.

Mike

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