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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: S6r Rx downloads
13/09/2019 22:45:55

Actually, it was a "hack" by me for erskyTx, and was added to openTx somewhat later!

FrSky did provide me with the updating protocol information so I could do it.

When trying to update devices from the PC, it is best if you power the device from a separate, switched supply. Get the updating software to the "Finding device" stage, then turn the power on to the device.

Mike

Thread: D8R-11 plus Receiver and EU LBT firmware
12/09/2019 09:29:46

Yes, someone else tested it on a D4R-II, I don't have any myself. I added the option of a SBUS output on channel 4 for the D4R-II.

Mike

09/09/2019 23:50:38

For those wishing to use 'D' receivers, particularly with new "ACCESS" transmitters that don't support D8 mode, I've written new firmware for them that uses D16 mode. Details are here: **LINK**.

I test flew a D8R-II yesterday with this firmware and a Taranis plus. The Tx is still using "international" firmware (it is pre-2015). The 2 flights had no problems. This firmware actually supports both international and EU-LBT modes, and properly listens before transmitting telemetry data. You also have the option of using one of the servo outputs as a SBUS output.

Telemetry is still the hub protocol in to the Rx, although this is sent to the Tx in SPort data. I'm looking into being able to use the Tx and Rx signals, combined with a diode or transistor, to support SPort sensors.

Technically, D8 mode is no longer legal, for new equipment, in Europe, but is OK for equipment imported before 2015.

Mike

Thread: Cable tidy using sbus
29/08/2019 00:11:42

I have written a program that run on an Arduino Pro Mini, takes SBUS in and provides up to 16 servo pulse outputs, program and instructions here: **LINK**.

Take care if reducing the number of wires that the power and ground wires left are capable of carrying the current for all the servos/retracts in the wing.

If using two receivers, make sure only one one is configured to send telemetry. As an alternative to using links when binding, recent firmware on the X6R/X8R allows the channels and telemetry options to be configured from the Tx when binding.

Mike

Thread: Latest CAA Update
28/08/2019 17:22:36

Tim, I wondered that as well when I read (on the BBC site):

"One standard effect of proroguing - or suspending - Parliament is that legislation currently being examined by MPs falls away. "

So you may be correct that it will have to start again.

Mike

Thread: X9D+ 2019 or Q X7S?
26/08/2019 15:22:17

I'm very close to having this D16 firmware for D8 receivers fully working. I've started a thread on RCGroups where I'll be posting instruction and the firmware: **LINK**.

The initial configuration available will be:
8 servo outputs, Hub telemetry on Rx, and the option of SBUS on channel 8 instead of a servo pulse.
Failsafe is settable either from the Tx or by using the button on the Rx.
Both FCC (international), and EU-LBT fully supported (including a listen before sending the telemetry data back and not sending if the channel is occupied). You select which at bind time, it starts binding in the same mode as the last bind, but a press of the bind button swaps modes

Following a request, I've also added a "dual bind" feature. If you bind to one, Tx, then bind to a second Tx, the Rx remembers the details of the first Tx, while still only being bound to the second one. If you have the first Tx operating in bind mode when you turn the Rx on, it will re-bind to that Tx, no need to press the bind button. The details of the second Tx are then kept so you may re-bind to that Tx. At any time the Rx is only bound to a single Tx.

Changing to this firmware is "one way only" as the chip needs to be fully erased to be able to flash the new firmware, so losing the original firmware and bootloader.

I've tested in both FCC and EU-LBT modes with a Taranis, Taranis plus, QX7, and a X9Lite (ACCESS in ACCST mode). All work fine. I've still to do a full range check but on my drive at home the X9Lite was still working when I was 45 paces away (in range check mode) on the other side of the road.

Mike

Thread: Possibly going all electric, which motors should I use?
26/08/2019 15:08:03

What radio gear do you use? I ask as I use FrSky and have recently started to use the FrSky Neuron ESC. This provides all the telemetry data for the motor, such as voltage, current and RPM, as well as the possibility of setting a maximum current to protect everything.

Mike

Thread: Sennybridge jamming trial
22/08/2019 11:17:48

They don't mention the 868MHz band, I wonder if that is included?

Mike

Thread: Prop size and efficiency
19/08/2019 12:23:24

I'm curious as to what formula you used for the "Volume of air per rev (cubic inches)" value.

For a 7x5 prop you have 3023.35. I would expect the calculation to be 3.5 * 3.5 * pi * 5 (as in pi * radius squared * pitch) for which I get 192.42.

You appear to have used (3.5 * pi * 5) squared!

My understanding is you need to consider the velocity of the air moved as well as the volume (mass) moved. The energy imparted to the moved air is kinetic energy, so is 0.5 * mass * ( velocity squared). This means a larger prop of the same pitch as a smaller prop, but rotating more slowly, will move a greater volume (mass) of air, but with less velocity. The energy imparted to the air may then be less.

Calculating this energy for the 7x5 and 10x5 props for the first motor in your list, I find the 10x5 is only about 16% "better" than the 7x5, as opposed to about 53% from your spreadsheet.

For electric power, there are electrical losses, and these are mainly due to the current flowing, and proportional to current squared. Moving to a lower voltage, and hence a higher current is likely to increase these losses, and the extra loss may be more than any gain from a larger prop. Personally, I try to use a higher voltage with a lower Kv motor to reduce the current while driving a larger prop.

Mike

Thread: X9D+ 2019 or Q X7S?
14/08/2019 20:53:48

Posted by Peter Christy on 14/08/2019 08:42:54:

I would expect QX7s to have Access in the near future as well. It may even be possible to do a firmware upgrade to the new protocol at some point, as I seem to recall reading somewhere that FrSky would offer this to hardware that was capable of supporting it.

Pete

My understanding is ACCESS will not be supported by a firmware upgrade as FrSky do not want to make the ACCESS firmware accessible by putting a logic analyser on the connections between the processor and the RF chip. The ACCESS hardware uses a single chip with both processor and RF on it so the signals are not accessible. FrSky even grind the identification off this chip (although I can make a guess what it is!).

Any upgrade to older radios is by replacing the RF module.

FrSky are also dropping support for the older 'D' receivers with ACCESS. This is partly because the 'D' protocol is not legal in the EU for new products. I'm in the middle of producing new firmware for D8 receivers that uses the 'X' protocol. I have something working (FCC version so far), that controls servos and sends some telemetry back for the two analog inputs and RSSI.

Mike

Thread: S6r Rx downloads
09/08/2019 17:35:11

The failure to write from V1.4 has been reported by others (on RCGroups).

I managed to install the Freelink tool, in spite of the installer being in Chinese, and this worked OK with the STK to a S8R.

Another alternative is to install the "SportSet" tool I have written. See this post for details: **LINK**, and post 8682 on the same thread gives more detail.

Mike

Thread: Registration of flying sites with NATS/ATC
04/08/2019 12:05:08

Not that being listed stops overflying by light aircraft. I fly at one of the listed sites and we had a full size fly over quite low last Friday. I could almost read the registration. I wasn't flying at that time, but I did have my Cularis at over 700 feet during a couple of flights, I reckon the light aircraft was lower than that!

Mike

Thread: Build your own telemetry sensors.
31/07/2019 12:45:35

Where did you get the Arduino IDE from?

Mike

Thread: Differential thrust mix.
26/07/2019 00:13:22

For electric, I'd recommend reducing one throttle with a rudder mix, never advancing a throttle, otherwise you could end with the situation a motor starts up when only rudder is applied.

I found I needed some differential throttle on my BH Mosquito for taxiing, otherwise it just would not turn.

Mike

Thread: Moon landing
20/07/2019 20:02:26

Why do you expect to see a "flame" from the rocket motor? Unlike the Saturn V first stage that uses kerosene, the lunar module uses hydrogen and oxygen, flames are mainly caused by glowing carbon.

For the landing, remember the rocket motor was not that powerful, it was only working against 1/6th of earth gravity. It is also mounted on the descent stage, so is a bit further away from the astronauts than you might think.

It appears that: "Apollo flight trajectories bypassed the inner belts completely, passing through the thinner areas of the outer belts"

Mike

Thread: Phil G's Frame Divider for S-Bus
16/07/2019 21:55:14

SBUS is still 9mS, and I don't expect it to change. Too many users feed it to a flight controller (e.g. betaflight), and want the 9mS rate to minimise latency.

My own SBUS decoder (on Github), using an Arduino Pro Mini, outputs 16 channels, at an 18mS rate. However, If I see a change on the SBUS 9ms after a pulse has been output, I send another pulse to minimise latency, but then revert to pulses every 18mS for a short while before allowing another pulse to be sent "early".

Mike

Thread: S8R stabilisation problemsanyone
12/07/2019 12:33:04

"latest" as a description of the firmware you have flashed is a bit vague! Do you mean the 20190531 version for the S8R?

Mike

11/07/2019 22:56:41

Is the Rx in "Quick mode"?

Mike

Thread: 9XD+
11/07/2019 22:43:38

The X9Lite runs both erskyTx and openTx. The internal module uses the new ACCESS protocol, but this now includes D16 mode. D8 mode is not legal in Europe for new radios as it doesn't conform to the the bandwidth use or LBT.

Mike

Thread: Number of channels?
11/07/2019 14:32:08

Both the X9D+ and the QX7 use an internal XJT module that fully supports 16 channels. For the receiver you either need 2 receivers, each providing 8 direct servo outputs, or you need to use the SBUS output that provides all 16 channels, for which you need either SBUS servos or a SBUS decoder. From a single receiver (e.g. X8R) you still get 8 servo outputs as well as the SBUS, so you may drive 8 servos directly, and only need the SBUS for the other 8.

If you have used an Arduino for anything, I have SBUS decoder code that runs on an Arduino Pro Mini and provides all 16 channels as servo outputs.

For the transmitter you also have the choice of erskyTx firmware as well as openTx. Many users find navigating around the menus, and setting up models, easier on erskyTx.

Mike

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