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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: Taranis to Spektrum Trainer.
09/05/2018 18:58:15

Yes you may map the trainer input channels in any order you like. You also have a calibration setting so you set the trainer input centres and also you may scale the inputs. Spektrum tends to only use about 80% of the channel range the Taranis does, so you may wish to scale the inputs by a factor of 1.2 to match.

Only the first 4 trainer input channels are directly handled in the trainer setup, but the trainer inputs also appear as mix sources (TR1 to TR16). They were renamed recently from PPM1 to PPM16, but still appear (in Companion) named PPM1 to PPM4 in the trainer calibration.

You also need to use a special function to assign a switch to swap to using the trainer inputs. You also have the option to pass only some of the 4 main inputs, so the instructor could, for example, keep control of the throttle while passing the rudder, aileron and elevator to the student.

In passing, in ersky9x firmware I have 4 "trainer profiles" available, so if you do a lot of instruction you may have the trainer setup for 4 different student transmitters, and simply select the one you require.

Mike

Thread: Throttle cut button - why the bad press?
03/05/2018 11:57:08
Posted by Martin Harris on 03/05/2018 10:50:27:

. . .sticky throttle systems are brilliant but rely on relatively complex programming - not everyone has the ability to program them or even follow a set of instructions.

Which is why, on ersky9x firmware, I have a "Safety switch" menu where you just select the "Sticky" type and set the controlling switch and output value for the throttle channel, no complex programming.

Mike

02/05/2018 17:24:44

I also use a throttle disable switch with electric, and have for many years. It is automatic for me to switch to the "safe" position before handling a model. Specifically, I use a "sticky" throttle disable, where, once disabled, it doesnt allow the throttle output to change from minimum unless the throttle stick is moved to minimum, so if the throttle stick gets knocked, and then the switch is changed to "enable", the motor still won't start.

I have this in ersky9x firmware as a simple "safety switch" selection, but it may also be implemented in openTx with some logical switches and special functions.

I'm curious regarding a club insisting that the battery is not connected until you are at the flight line, how do you deal with range checks when the radio needs the battery connected?

Mike

Thread: Companion2.2 - Taranis X9D anomalies
02/05/2018 17:09:12

Check in the radio settings that LS and LR are set to "Slider with Detent" as opposed to "None".

Mike

Thread: Who wants a Warbird Replics Hurricane?
30/04/2018 16:52:50

Making slow (by possibly steady) progress. I've bolted the wings on, the retratcs and flaps are complete, except for linking the outer flaps to the inner ones.
All the servos are in. and the weight at present is around 60oz.

h1.jpg

h3.jpg

h4.jpg

h2.jpg

Rather than use the dihedral braces, I've opted to use fibreglass cloth and resin to join the outer wing panels to the centre section.

The outer flaps have a 3mm dia carbon tube at the front, with a 2mm carbon rod inside that extends beyond the flap to form the hinge.

Mike

Thread: Battery problem
21/04/2018 22:06:39

I agree to not charging lipos unattended, but where are you getting information from regarding NiMhs?

Many devices have inbuilt NiMh cells that are on continuous trickle charge e.g. cordless 'phones. They don't say "don't charge overnight"!

A 2500mAh NiMh may be charged at 250mA for 24Hr, at 70mA they will be fine for months. From flat at 70mA they will take around 36 hours to fully charge.

Mike

21/04/2018 18:28:25

Mistreating in what way?

Low current trickle charging is fine, and doesn't damage NiMh cells. For example, I just checked a datasheet for a 1100mAh AAA cell. This specifies you may charge at 45mA for a year continuously! As I mentioned above, only using a "smart" charger will lead to cell imbalance over time, so then you will need to do a trickle current charge to balance a pack.

Mike

20/04/2018 23:41:23

What capacity are the batteries? As long as they are at least 700mAh, then a trickle charger of 70mA may be used. NiMh batteries will handle being charged at 1/10th 'C' for over 24 hours, indeed, this type of charging is needed to ensure all the cells are fully charged (balanced).

Even if a "smart" chrger is used most of the time, a trickle charge is needed occasionally to 'balance' the pack.

My NiMh batteries have lasted for many years without any problems.

Mike

Thread: Turnigy 9X range issues?
20/04/2018 09:34:59

Is that the 9Xtreme board?

The original RF module should work fine still.

If you want to use the Orange module, you might consider updating the firmware on it to the version that uses the Multiprotocol, see this thread: **LINK**.
The original firmware on the module didn't work well with some "BNF" models, in particular the throttle didn't respond.

Mike

Thread: S6R receivers
19/04/2018 22:26:18

Download the latest manual from here: **LINK**.

You have "Quick mode" available on new receivers (it is the default mode), and you also get it if you update the firmware on the receiver.

Mike

19/04/2018 16:47:18

There is a new download of firmware for the S6R/S8R available, which a description of "Fix the Bug"!

I've found out that the change is to remove the flashing of the blue Led on power up when in "Quick mode". It seems the Rx didn't start operating while flashing the blue Led, so was slow to recover from a brownout when in "Quick mode".

Mike

Thread: The 2018 Transmitter Survey!
17/04/2018 13:08:03

One thing that FrSky do is listen to users and developers. When they were developing the XJT module, I had PXX protocol firmware for the DJT module to test (back in 2011). When developing the Taranis, developers received prototype units. We gave quite a lot of feedback on the hardware design (which FrSky changed), including making sure even the original gimbals were good quality, as well as porting ersky9x/openTx to the radio.

Most of the time, if there are problems reported back they fix them and provide updated firmware (and even hardware mods) as a result.

Open source firmware developers are also provided with documentation (circuit diagrams, protocol specifications etc.), so are able to provide a level of support on these forums to end users.

After a number of problems with the S6R (stabilising receiver) firmware, I received a S8R from them to test before it became available for general purchase.

In the US, Aloft hobbies provide excellent support for FrSky equipment, which provides a significant level of "word of mouth" advertising.

Of course, since the Taranis uses open source firmware, the development cost was much lower, which is one reason the price point of the radio is lower than some competitors.

Mike

Thread: Safety plug
13/04/2018 16:09:22
Posted by Bryan Anderson 1 on 13/04/2018 13:08:54:

The reason why the turn-off transient is less stressful is because
a) the current from the battery is usually minimal when disconnecting
b) the energy stored in the capacitance would typically be an order of
magnitude greater than that in the inductance so the ability of the
latter to cause overshoot is minimal.

This is true for the turn off transient when disconnecting the battery, but during normal operation the ESC switches power between the outputs and, particularly at throttle settings less than full, switches the current on and off.
This switching therefore causes voltage transients in the wires between the battery and the ESC.

Since this switching also operates at something like 8kHz or higher, these transients occur at that frequency. The result is that the capacitors at the input of the ESC are repeatedly charged and discharged at this frequency by the voltage transients.

Longer wires result in a higher inductance and so a higher transient voltage. This higher voltage then causes a higher current into and out of the capacitors. For the capacitors to handle this alternating current they need to have a sufficiently high "Ripple Current" rating (which is helped by them having a low ESR rating).

If the capacitors don't have a high enough rating, then they heat up. Electrolytic capacitors tend to "dry out" over time and so lose some capacitance. If they heat up, this drying out occurs sooner. Eventually the capacitor fails completely at which point the transients are applied directly to the rest of the electronic circuitry, usually causing a catastrophic failure of the ESC.

Adding extra capacitors to long wires, reduces the voltage transients due to the higher capacitance, and also reduces the ripple current in the capacitors as the current changes are shared between them.

I did try to work out the likely ripple current in the capacitors once, and came up with a value that suggested the capacitors on most ESCs were being run well beyond their ratings.

Mike

Thread: FrSky X10 - Taranis replacement?
10/04/2018 23:27:27

The Taranis and QX7 only have a 32K byte EEPROM fitted. This means, even with data compression, that you can't save 60 complex models in it. The Horus doesn't have any EEPROM so models are stored on the SD card.

What has happened is openTx, for ARM processor based radios, was first implemented on the SKY upgrade board for the 9X radio. This has a 512Kbyte EEPROM. openTx opted to allow for 60 model memories. When then implemented on the Taranis (prototypes had a 64Kbyte EEPROM), the number of model memories was kept at 60, but there has always been a problem actually storing 60 complex models. As time has gone on, with more features being added, each model has needed more storage space. I think that a number of name fields were therefore reduced in length to allow more models to be stored.

Mike

Thread: Your Transmitter History
09/04/2018 23:29:27

Remcon kit + other make of kit Rx
Homebuild from Sprengbrook circuit (also Sprengbrook linear servos with own design servo amplifier) + Micron kit Rx
Digifleet XP/FM
Hitec Eclipse 7, 35MHz then FrSky 2.4GHz module
FrSky Taranis
FrSky Taranis Plus and Taranis QX7 - currently in use
I also have the following in use for firmware development::
9X with voice mod
9X with '2561 CPU and voice mod
9XR-PRO (2 off)
9X with SKY upgrade board - occasional flying use
9X with 9Xtreme board
9X with AR9X board
9X with AR9X board fitted with '4S8 CPU
FrSky Taranis X9E
Prototype FrSky Taranis and Taranis Plus
Prototype FrSky Horus

Firmware on all these radios is er9x/ersky9x

Mike

Edited By Mike Blandford on 09/04/2018 23:35:15

Thread: FrSky Taranis - user chat
02/04/2018 15:58:35

I've also now posted another "app". This one, called "ChangeId.app" lets you change the physical Id of a FrSky sensor, useful if you need two of the same type of sensor (e.g. FLVSS for more than 6 cells).

Mike

27/03/2018 10:55:40

In ersky9x firmware I have a "maintenance mode" that provides several features including the ability to flash internal and external XJT modules, change the SPort ID of sensors and flash Multiprotocol modules. Some of these features have been included in openTx, but others have not, and my not get included, or may tak a long time before they do get included.

I've been looking in to this and have a possible solution that doesn't rely on openTx being changed.
On the Taranis, the bootloader runs in RAM, but uses less than 64K of the 128K available.
I have changed my bootloader to include a new option "Run App". This loads and runs a program from the SD card, using 64K of RAM (max of 32K currently for the "app" code) located in the second 64K of RAM.

My idea is to have an "app" that just does the flashing of a MultiProtocol module, and then others that allow for different functions.

To use such a facility does not require openTx to be modified, just flash an alternative bootloader, then run an app from there to carry out these sorts of functions.

I've just posted a test version of ersky9x (ProvR222a2) (**LINK**) for the Taranis, Taranis Plus and the QX7(s). The bootloader in these has the options of "Flash Firmware" and "Run App". I haven't had the "Restore EEPROM" in my version of the bootloader, so I don't have that available (yet). I'll either add that, or make it another "app"!

The .zip file also includes an app for each of these transmitters, you need to use the "app" that matches your hardware.
Each "app" includes an identifier of the hardware on which it runs. The bootloader checks any "app" it loads and only runs it if the identifier matches the bootloader.

To use this with openTx, just copy the required .bin file to your firmware directory, and copy the required "app" file to an "apps" directory.
Use openTx to update the bootloader on the radio from the .bin file.
Now restart the radio in bootloader mode, choose the "Run App" option, then select the "FlashMulti" "app".

Mike

Thread: Who wants a Warbird Replics Hurricane?
14/03/2018 16:03:49

I've been progressing the wing centre section and now have flaps fitted and working and the retracts all glued in and working.

The next step is to attach the outer wing panels. The plan shows 38mm dihedral under each tip (not quite sure exactly where this is measured, the absolute end of the balsa block or the end of the veneered part). The instructions say the outer panels are already made to give the dihedral, but when I "dry fit" them I get very little dihedral. It looks like I shall need to sane the root of the outer panels to fix this.

Mike

Thread: S6R & S8R Receivers
11/03/2018 16:56:54

I find flying with auot-level on very odd since it tends to fight any control input you apply. For example, normally, when you apply aileron to bank the model, when you reach the required bank angle you centralise the aileron (you don't want to roll!). As the model turns, with the 'outside' wing moving faster than the 'inside' wing, the model may try to increase the bank angle, so you end up applying a small amount of 'opposite' aileron to hold the bank angle.

With auto-level, you have to hold the aileron on to hold the bank angle.

Up until now I've set auto-level on a switch so it only acts for 1.5 seconds, long enough to get the model level, but then revert to stabilise mode.

Next time I fly, I've set auto-level up so it only operates as long as the aileron and elevator are both centered. As sonn as any control input is applied, auto-level switches off.

Mike

06/03/2018 23:07:47

Yes, as it says under "SportSet(9).zip":
"Only the .exe in this .zip, install from SportSet.zip first, then copy this .exe to the same directory".
This will install the required .dll files. I do this as the full install is 5Mb, but the .exe is only 143kb.

Usually that is caused by the self-check having been run when channel 5 wasn't being driven, so the Rx has "remembered" zero movement. Try running the self-check again, and re-calibrating the servo limits.

Mike

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