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: lipo battery charger|
Many answers, as usual, to this sort of question.
I got one of these earlier this year: **LINK**
Mains or 12V battery input, two independant outputs and also does the ESR measurement. I also have a GTPOWER A8, so I also sometimes have 3 batteries charging at the same time.
|Thread: Which Set Should I buy|
Most of our radios currently don't have the equivalent of a mouse/clicking or a touch screen, so this limits some of what may be achieved. The screen resolution also limits things.
I have made a significant effort to make things easier to find in ersky9x firmware. When you go to edit a model you first get an "index" display where you may select the "type" of item you wish to change:
I'm open to feedback to make this even easier to use.
Perhaps you could define what an "intuitive interface" actually is.
|Thread: Returnee to EF seeking advice|
You aren't restricted to openTx on most FrSky radios (and some others as well), you also have the option of ersky9x firmware.
As an example, here is the menu index display (from a FrSky QX7) you get when editing a model. The menus are, in my opinion, easier to follow and find settings than in openTx.
BTW PatMc, my QX7 does have a slider. I added one, and used one of the coloured LED outputs for the switch as the extra analog input. A slider is far more use than three colours for the power switch LED.
|Thread: Have I done serious damage.|
If the charger is 500mA, and the battery is 2500mAh, then it will take 5 hours to charge from completely discharged.
If you left it on discharging so it is very discharged, then you will likely find a "Smart" charger will detect a "false peak" very early when charging.
What speed controller do you have in the glider? You may need to configure it for NiMh batteries as it may be deciding you have a 2 cell LiPo and cutting off early when the NiMh voltage gets too low.
Also, what connector are you using from the battery to the speed controller? If one of the Tamiya type like on this battery **LINK** then you should replace it with something more capable as the Tamiya is not suitable for high currents. In my opinion, this type of battery should not be sold with that type of connector.
|Thread: TX talking to 2 RX's in different models at the same time?|
David, the "receiver number" is selectable, it is not specifically tied to a "model slot", so you may choose one for each model.
|Thread: Autumn is here...you been flying ?|
Depending on your transmitter capability you could try the following, it depends on your Tx having flight modes with trims specific to each flight mode.
Set up a switch to select "Landing" mode with a unique trim for elevator. Now just (at a good height) switch to "Landing" mode, shut the throttle then adjust the elevator trim to get a slow glide for landing. Makes things easy.
I don't consider this "cheating", I was taught to use the elevator trim (with flaps) on full size for landing.
|Thread: Make your bets please Ladies and Gentleman|
YMMV - Your Mileage Might Vary! Almost what you are saying anyway!
|Thread: Lipo Battery Storage|
A reason not to store fully charged is "fully charged" depends on temperature. A battery that is fully charged at one temperature becomes over charged at another (I think lower?) temperature.
I store my batteries at storage charge, which is 3.8V per cell according to my chargers. I usually take a charger ti the field with me, so after using a battery, unless I need to recharge it, I put it on storage charge, which usually doesn't take long.
|Thread: Battle of Britain Day|
I think he is asking why the "other" thread is titled "Battle of Battle" not "Battle of Britain", with an aside as though from the Polish pilots (in the BoB film) requesting "Repeat Please" as they peel off one by one to engage "bandits".
|Thread: Lipo charging|
Dave, that is exactly the circuit I expected.VT13, VD4 and L1 form a buck (step down) switch mode regulator, while VT15, VD5 and L1 for a boost (step up) switch mode regulator.
The chargers I have use the inductor in both buck and boost modes, converting the supply voltage to that required to charge the battery. They operate using the charge current to regulate the output voltage that is controlled by the PWM mark-space ratio. The PWM frequency used is sufficiently high that the inductor, with the associated output capacitor, produces quite a constant voltage/current, in the same way any switch mode power supply works.
|Thread: What gauge wire|
A bit difficult to see exactly what those waveforms are showing, and they don't look much like the ones I got on my digital storage 'scope, where I could capture and "freeze" them.
The ESC outputs are square wave voltage, and the non-driven wire shows a sinusoidal feedback voltage. The current is likely to be reasonably constant as the inductance of the motor tries to keep the current flowing, and the parasitic diodes in the MOSFETs provide a current path.
The motor, as you have said, includes inductance, in the same way a switch mode power supply uses an inductor. When operating a switch mode power supply in step down mode, the current in the output may be higher than the current in the input, the power in each is the same (except for losses). The same can happen with a brushless motor.
I've just put my 'scope on the wires to a motor. The pwm frequency remained fixed. The outputs to the motor followed a sequence of 6 "phases".
"A" at supply voltage, "B" pulsing low, "C" not driven.
On the wire that is not driven, you can see a sine wave, which is the induced voltage in the undriven winding.
(OK, a sample of size 1)
This is as I described.
BTW Kirchoff;s law is for a "node" not a circuit.
"the output current can never exceed input current" No, but there are capacitors on the ESC input that provide the "extra" current for the current pulses.
"Outrunner motors are essentially three phase ac motors" No, they are DC motors with electronic commutation.
The ESC connects one of the three motor wires to the positive supply, a second to the negative supply and reads the induced voltage on the third wire to time the commutation.
Yes, the inductance will limit the current rise, but actually sufficiently slowly that the current is essentially constant.
"you never have all of the current in one leg being opposed by an equal and opposite current in another" Yes you do as it is a DC motor, I just described how the commutation is done.
"how thick are the wires that form the winding?" About the same thickness as the wires from the ESC. You may look at the windings and see quite thin enammelled wires, but, for ease of winding and to get more copper in place, the windings are made of multiple, parallel thin wires.
|Thread: Horus X10S with Spektrum receivers|
The "patch" is actually to flash the multiprotocol firmware to the module. I created the changes to the multiprotocol firmware so it compiles and runs on the Orange module.
Instructions are available here: **LINK**
The power output may be adjusted in the multiprotocol firmware, the default is +4dbm from the RF chip, then amplified by power amplifier. The RF chip may be set to 0dbm if required.
With the bootloader on the module, you are ablue to then flashit using a FTDI type device, and on sme transmitters you may flash directly from the Tx using a file on the SD card. At present the X10(S) is not one of those as I've not got one so haven't ported ersky9x to it. On transmitters that do run ersky9x, I have added a feature to the Tx bootloader that lets you run an "app". If you are running openTx, you may replace the bootloader with the one from ersky9x, then you get this feature. One of the "apps" available is the one to flash the multiprotocol module.
|Thread: What gauge wire|
I'm not sure I agree with this!
Suppose that at full throttle you have 30A in the input wiring.
Yes, the average current in each wire is less, but the current, when it does flow is the same as in the input wiring.
Now suppose you reduce the throttle to have only 15A in the input wiring. The ESC has done this by only driving the output for part of the time. I think you will find you actually have 30A out on A and 30A in on B, but for only half of the first third of the time, and similarly for the other 2 thirds of the time. So the output wires are actually carrying more current than the input wires!
|Thread: Horus X10S with Spektrum receivers|
The openTx team are NOT supporting this Tx. The firmware on it has been forked from openTx 2.2, then has a few small changes applied to it. The hardware is a (cut down) copy of the FrSky QX7, with the rotary encoder replaced by buttons, so is running a near copy of the QX7 firmware. The firmware will have been compiled with whatever options Jumper have chosen, you don't get to choose as you do when downloading "official" openTx.
Basically, it seems, Jumper are simply copying the QX7 and the multi-protocol project, both of which support open source firmware. The T12 doesn't add anything that existing radios don't already do.
From a post of mine on RCGroups:
"The patch to openTx is very simplistic, and doesn't have all the conditional compilation needed for the T12 to become another supported Tx. Much more would need to be done, including adding support in Companion, for proper support.
The 4-in-1 module included uses the USB port with a USB-to-serial chip inside. This means the USB bootloader doesn't work. The module also has the incorrect chip for the serial inversion (00 instead of 86). This means it only works with inverted serial, and the "Flash from Tx" method has to use inverted serial."
The firmware is likely to be confusing as it includes support for things that are not present, e.g. settings for an internal RF module and haptic.
I do have ersky9x ported to this radio, and will be supporting it, but, as I did with the Turnigy 9XR-PRO, support for the FrSky 'X' receivers and SPort telemetry is disabled unless Jumper reach an agreement with FrSky that these may be included.
From another post of mine on RCGroups:
"A general comment regarding the multi-protocol module. Transmitters use a "unique ID" that is used when binding. Manufacturers produce their own transmitters so that this is unique to each Tx.
Edited By Mike Blandford on 08/09/2018 20:17:31
Yes, but as I said, you may find you cannot select the D8 protocol, particularly on an internal module in a FrSky transmitter.
I think that is incorrect. The XJT supports 'D' and V-II" receivers whether it has EU LBT firmware or international firmware, I just double checked by binding a LBT XJT to a D8R-II.
Where there may be a confusion is on FrSky transmitters running openTx (and possibly FrOS), if the Tx itself (not the module) has EU firmware, then the 'D' option is not available for selection in the menus.
Want the latest issue of RCM&E? Use our magazine locator link to find your nearest stockist!