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Member postings for Chris Bott - Moderator

Here is a list of all the postings Chris Bott - Moderator has made in our forums. Click on a thread name to jump to the thread.

Thread: Build your own telemetry sensors.
30/03/2020 22:37:37

Mike, see my post above, but - I just had another thought about your current reading.

You report an A3 voltage of 1.648 which is incredibly close to half of 3.3V - the supply volts.

Could your ASC758 be one of the bi-directional ones? These give a volts at zero current of Vcc/2

This shouldn't be an issue, though. We just need to set the MVOLT_PER_AMP to suit, and the MVOLT_AT_ZERO_AMP to 1648

30/03/2020 18:59:15

Hi Michael, it looks like you're so close.

If you change the voltage on A3 does the reading change?

You could do this by say, adding a resistor between A3 and Gnd.

This would test whether the software config is correct for using A3.

If the voltage is different but the reading stays at 230.1A then we need to look at the config.

30/03/2020 14:37:00

Hi Dennis

It's quite a while since I did that XT60 unit and to be very honest, I really can't remember. The resistor values were probably something I had to hand that worked for whatever I was doing. The important thing is that the input to the Arduino shouldn't ever go above the supply voltage, be that 3.3V or 5V.

The 47K from CRNT to ground was added purely experimentally, I was seeing good readings at 0 throttle and full throttle but not when at part throttle. Having assumed that tis was due to the DC being PWMd I tried a number of filter circuits, but the 47K seemed to be as good as anything.

I'm sure someone else has done much more with these sensors since, and may be able to help?

The choice of FRSKY protocols:-

FRSKY_SPORT_HUB is indeed for D series type telemetry.
FRSKY_SPORT is for the SPORT protocol used in X series receivers.
FRSKY_SPORT_HUB detects and switches to whichever in use. I understand that this detection isn't 100% reliable which is why the other two are provided. Having said that, it has always worked for me.

21/03/2020 16:21:32

OK I have 24 of these, still. (6 x 4)
As you can see the top one has correct resistor numbering so can always be referred to.


I'll send you a PM, Dennis.

20/03/2020 21:25:13
Posted by Michael Hadaway on 27/09/2019 12:49:14:

Hello. Sorry to be a bit tardy replying to your post. Due to health problems and other distractions I have put the project to one side for now.

I do have a working variometer and a voltage/current sensor using your supplied pcb give accurate cell readings but the standby current is reported to be about 130 A, with no VFAS detection.

I am using the latest sketch that has only config.h. not configbasic and configadvanced.

In config.h about line 130 there is define VFAS_SOURCE ADS_VOLT_6.

Suspect this line should be changed to VFAS_SOURCE VOLT_6

I don't like to give up so will continue when energy reserves return.

Hi Michael, I must apologise, I've only just seen your post.

I've just downloaded latest version and see it does indeed only have a config file called oXs_config.h

I'm not familiar with this version but it looks like a lot of work has gone into it to make it easier to understand configuration. The key is to read ther relevant section in oXs_configuration_description.h

It does look like you need to change that line 130 to define which voltage you wish to be used. I'd also think that the line:

// ***** 6.2 - Voltage parameters *****

needs the pins listing in order, to correspond to the PCB layout. Thus generating Voltage_1, Voltage_2 etc etc - in order.

However: I think your rather large curent offset is likely to be caused by the line:

#define MVOLT_AT_ZERO_AMP 2500 // in millivolt

needing correcting by measuring the sensor output voltage at zero amps and entering that value here.

20/03/2020 21:06:25

Thanks Peter.

That could prove very useful if anyone needs one once I run out.
(Or particularly wants some with correct screen printing).

You never know, someone might pick this up as a self isolation project?

20/03/2020 20:51:44

Hi Dennis and welcome.

Do you mind if I have a look in the morning?

I'm fairly sure that the situation is this:-

I may have one or two of the latest version boards.

I'm sure I have plenty with the incorrect resistor numbering, these are electrically correct and work fine. They're not difficult to work out.

I'd like to check though and will send a PM here once I have.

PS - I ordered some PCBs for a different project over a month ago and there's no sign of them yet, so I think in the current climate, I'll not be placing an order for more sensor ones any time soon.

Thread: FrSky Neuron ESC
14/03/2020 20:41:44

Good news that you found something, Bob.

I assume you can watch both RPMs throughout the throttle range to check?

I'm sure you could set up some RPM monitoring to monitor the difference and either let you know, or even do something like cut both throttles, if the difference got too big.

Oh and I'm certain you already have, but do make sure failsafe is set correctly for both throttles channels.


Edited By Chris Bott - Moderator on 14/03/2020 20:42:45

Thread: Multiprotocol module
10/03/2020 13:21:01

Thanks Mike.

Currently supplier is liaising with Jumper and they are asking for tests, just to see if it can be sorted this way. But I'm sure that in the end it will be replaced.

Watch this space.

09/03/2020 16:16:55

I'd already tried a new download of the firmware.

I've now tried the previous version. All to no avail. OpenTx is now suggesting that it should be updated.

The FrSky stuff does have telemetry (with a link quality reading I'd not seen before) but the Focker doesn't. So I don't think we can blame telemetry.

An enquiry has gone to the supplier. We'll see how they respond.

09/03/2020 13:10:57

Thanks again for the suggestions. I thought I'd post an update - with a question.

So, a jumper 4 in 1 was aquired. It had no controls on the back, just 2 LEDs and a USB socket. That's fine, I'm using it with OpenTx in serial mode.

My Horus X12 was already up to date at 2.3.5 so the options were available there.
The X12 screen showed me that the module came with 4 in 1 firmware installed.

A quick test showed the unit bound fine to Spektrum receivers but one main use would be for Hitec equipped BNF indoor models and this wasn't working.

So a firmware update was required. Version is too old to update from Tx.

The windows app "Flash-multi" was downloaded along with "multi-stm-opentx-aetr-inv-v1.3.0.53.bin" and the upgrade went perfectly.

Now, using menu option Hitec-Minima the Ares Focker D-VII bound straight away and worked very nicely once I'd set the channel order to AETR.

I also bound an old Micro Stik using a protocol called FlyZone FZ410.

Next I found that there's a "FrSkyRx" option which can be used to receive from another Tx for training and I found the Specrum analyser. All very impressive.

So on to a problem that I have my own theory on.

The Focker, on Hitec and both FrSky D8 and D16 (EU) are now working to start with, after every switch on. But after 2 to 3 minutes the connection is lost and can not be made to work again without switching the Tx off for 5 minutes.

Spektrum continues to work as long as I leave it switched on.

Hitec & FrSky protocols use the CC2500 RF Module.
Spektrum uses the CYRF6936 RF Module.

As another test I've moved the module to an old Taranis X9D, fully upgraded that and I get exactly the same fault sysmptoms. Working for 2-3 mins then stops. Needs a few mins off, then it works again...

I've tried the frequency fine tune and that appears to be doing as expected - finding both ends where the link drops, then set the value to the middle of that range. But that's ony if I do it in the first 2-3 mins where things are working.

So what are your thoughts? Do they concurr with what I'm thinking? Or is there a fix that I'm completely missing?

Thread: On board volt & amp meter
06/03/2020 19:13:23

Which radio do you use Chris?

Depending on the radio, this can be just as easy to do via telemetry and see the numbers on the Tx display. Then, you don't need to carry a display on the model.

Thread: Multiprotocol module
05/03/2020 16:50:23

That's all excellent info from everyone in very quick time. Many thanks.

I'll have a good read. Sounds, ideally, that I should get one that has plenty of memory and that is usb capable out of the box (Just out if laziness).

There seem to be a few processor options available. Does that matter?



05/03/2020 16:03:22

I've always liked the idea of a multiprotocol module for my FrSky Txs but have never quite taken the plunge.

So just which one is the one to buy now?

I'd particularly like to have support for Hitec protocols.
Would I need to update the firmware?
Is this now possible through a USB socket from the off?
If not vis USB, then how?

I think I also read about some fine tuning being needed for some protocols?

Any recent experience would be really useful.

Oh PS : - What sort of range do they have. Primary use would be for indor models, but outdoors might be useful too.


Thread: BMFA Membership Card
21/02/2020 11:09:20

It does look a good option and will take very little effort to recover the cost, should you even feel the need to.

After that, it's up to you what you get out of it.

Maybe we should have a competition for the best savings?

21/02/2020 10:31:22

Gary there seems to be a lot more retailers listed now I have my card and am logged in.

Andy - Do you just present the card at the checkout? It's not actually clear. When I'm in the rewards website and go to a specific retailer theres a bit of a description of the retailer and the option to buy their branded reloadable cards at a discount. I'm hoping that is just another option, rather than being the only (tortuous) way to use the discount?

Thread: FrSky Taranis - user chat
02/02/2020 19:59:55

Thanks John yes, now you mention it, that had registered with me before.

Tx keeps D8. X Series Rxs lose it.

I guess if you really needed an X8R to do D8 you could flash it back in seconds.

02/02/2020 16:30:16

Also -

  1. Upgradingto ACCST V2 needs doing on TX and Rx before they will work together so once Tx is done, all Rx will need doing.
  2. Upgrading appears to remove the D8 protocol.
  3. Upgrading stops any compatibility with clone equipment. Cynics might suggest that this is FrSky's motivation all along.

02/02/2020 16:20:38

As I'm more and more prone to "senior moments" (I think) can I just clarify what we're talking about here? If I'm wrong, please correct me.


  1. Recent chat has been about the ACCST D16 2.X.X RF module update that FrSky have recently released to fix a pretty rare bug.
  2. Most people who have, have installed this without issues but some have had problems. In particular with early (none plus). Taranis X9D.
  3. The RF firmware is available from FrSky and can be installed from OpenTx if you have latest OpenTx.
  4. Bob's link above is to a version of the RF code that you'd need should you wish to revert back to the original ACCST V1.
  5. ACCESS is a completely different new system that's appearing on new transmitters. There's also a Horus X10 hardware upgrade for ACCESS.

Edited By Chris Bott - Moderator on 02/02/2020 17:00:26

Thread: The RCM&E 60th Anniv' Fly-in 2020 at BMFA Buckminster
01/02/2020 08:21:44

I'm really looking forward to this, the 2019 event struck just the right note as a friendly fly in and the Buckminster site is excellent.

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