Futaba M6 Fr Sky 2.4 ghz DIY Conversion

[Phil Green]

If you take one of the map statements:

chan03=map(analogRead(A2),335,697,1000,2000);

697-335=362, so there are 362 actual ADC steps between stick extremes. The map function maps the 362 real steps to a range of 1000 'theoretical' steps.
1000 not being a multiple of 362, integer rounding will mean that occasionally there will be a double step where two adjacent 'real' steps equate to the same 'theoretical' step, sorry I know I'm not explaining it very well!

Maybe its not a problem, I was just pondering it thats all

Cheers

Phil

[Paul Luby]

Hi Phil

Ok got what you mean. As you say though is it an issue?

Given we're feeding varying control signals at approx 50 times a second and the chances of some of our older stick mechanisms being that accurate around any value, is it an issue?

Think you've answered the question yourself mate.

Paul

(AKA Veri-Gash)

[Phil Green]

Yeah, you're right !

[Phil Green]

I had a look at your link DJC and its the Patolin one again from RCG. I like the wooden case though!

Ta v much

Phil

Edited By Phil Green on 26/06/2014 21:33:20

[Paul Luby]

Hi Guys

Just took delivery of the Tx that I think will photo best for an RCM&E article. I think it will photograph better that the older black Custom III set I have and I'm sure there are many XP/FM sets out there.

Got it off e-bay for £20, included everything in picture.

If you know of anyone who wants some Digifleet Rx's and servo's, I have quite a collection now and would be looking for a buyer as I only need the transmitters.

It's got separate trim pots so that'll mean a little extra code but will look good.

Paul

(AKA Veri-Gash)

Edited By Paul Luby on 26/06/2014 19:17:39

[Phil Green]

Still got my 27m AM Digifleet Custom 2, still works but its badly marked - the 'Fleet' badge is only vinyl and its become badly creased over the years. Kids used it for model car racing so it got thrown around a lot!

Is your RCM&E article a go-er then Paul? thats good news! DG maybe you could add your buddy project too, to show there are endless options... and maybe a photo of Chris's Waltron?

The prospect of more "&E" is good!

Cheers
Phil

[Paul Luby]

Hi Phil

I think so.

The last com I had with the Ed stated that he's confident there's and article in it if I want to write it. I'm assuming that means write it, send it in and see what happens.

Paul

(AKA Veri-Gash)

[Phil Green]

Go for it Paul, they are very good at the presentation side if you just do the words.

Plus you get a bit of pin-money to fund the next project! Bonus!

[Phil Green]

Just added the single-handed range test, invoked by cycling the channel 6 toggle rapidly three times.

Throttle is held 'off' by range-test mode, rudder automagically waggles side to side and other channels work normally. This so you can leave the tx somewhere & walk away with the model, watching the rudder as you walk.

Elevon mixer next I think

Edited By Phil Green on 24/07/2014 18:19:06

[Phil Green]

Bought an icsp programmer for twopence-ha'penny off ebay, it arrived this morning & works great, so I've ditched the nano's bootloader and the encoder now runs immediately on power up.

Normally theres an inherent delay after power up where the arduino waits for comms from the IDE for a couple of seconds, and then runs the user prog if it sees nothing.

This delay was messing up the 'stick-held-on-power up' things like reversing etc, all sweet now the bootloader is gone. I know you prefer the switches Paul, its just that all my pic encoders use this method of reversing so its a bit of consistency. I managed to find a Noble slide switch to repair the broken Kraft one (top left of the case) so I can use that for another function now, dunno what yet, but it was a lucky find, these things are 40+ years old!

Cheers
Phil

[Paul Luby]

Hi Phil

Each to his own, I have a ch340g device I use to program my Pro Mini's.

Never thought to see if I can hook it up to other Arduino's.

Might give it a go for a giggle.

Paul

(AKA Veri-Gash)

[Phil Green]

Its because there arent any spare inputs for reverse switches on the 12F675. Its only an 8-pin device and all the pins are used, so you have to do it another way, hence the 'hold-sticks-whilst-powering-up' idea. The S/C circuit board is really versatile but admittedly the 5ch propo encoder is stretching it a bit, this one is much better in many respects, so thank you for getting me interested in arduinos Paul!

Incidentally theres another reason for dumping the bootloader - for anyone who uses Corona modules (as at least 3 pals do) its essential - if a Corona module is powered up with no PPM, even briefly, then it defaults all channels to 500uS which if the rx is on usually winds all the servos to one end and strips the gears. The bootloader delay is well in excess of the servo transit time, so if the tx was switched on after the rx, Coronas would strip servos every time the tx was booted. Without the bootloader the ppm feed is pretty instant so no probs

Cheers
Phil

[Phil Green]

For anyone who fancies a go but is put off by soldering, you could connect all the sticks and switches using one of these:

£1.92 post free!

**LINK**

I had a problem with the only Nano board I ordered from HobbyKing, probably one-off bad luck but the ones I bought from ebay for £4.26 have been spot on:

**LINK**

They come as cheap as £2.52 if you're hard up! Maybe less if you shop around!

**LINK**

15-way Header sockets are cheap:

**LINK**

Edited By Phil Green on 30/06/2014 18:44:30

[GONZO]

Phil,

got a link for the icsp programmer you got from the bay? Downloaded software from the Arduino site and done lots of reading but am still waiting for nano's from HK, it'll be four weeks soon from when they said they had been dispatched. Hope they don't have any problems when/if they eventually arrive.

[Phil Green]

Hi Gonzo, this is the one I bought, there are loads to choose from.

**LINK**

The drivers aren't supplied but are easily found, I used the XP ones:

**LINK**

I put heatshrink shrouds around the board & adapter as both are supplied bare.

Incidentally, 5v leds are handy when you're experimenting, no resistors to faff about with:

**LINK**

Re the wait for nanos from HK, do you want one of mine? I've one spare, I can post it tomorrow?

Cheers

Phil

Edited By Phil Green on 29/06/2014 23:35:44

[Phil Green]

Elevon mixer is done & working well, at a fixed ratio of 75% aileron & 25% elevator which seems to be about the optimum for slope wings. To switch the mixer in & out, I'm using the now-redundant scope trigger output wire on D10 as it saves me removing the encoder again to solder more wires. That goes to the repaired slide-switch (top left) so it grounds the wire to enable the mixer. Leaving D10 open circuit (input_pullup) disables the mixer & the channels then work individually as normal. For the moment I cant think of anything else to add as its supposed to be a really simple no-frills encoder, just need to fly it now!

The mixer section is just before ppmout:  (still cant get over how easy these things are!)

// check if mixer switched in
if (digitalRead(digi00) == 0) {
channel[0]*=.75;
channel[1]*=.25;
chtemp=channel[1];
channel[1]=channel[0]+600-channel[1];
channel[0]+=chtemp;
}

Spec so far is:
Chassis - Kraft Series 71, guts replaced with arduino nano
Frsky 2way or 1way switchable, extended bind button to 'trainer' & led behind Kraft meter
6 channels, 4 propo, one toggle, one momentary pushbutton   (several 'spare' analog & digital inputs)
Self-calibrating sticks, saved to EEPROM during power-off - no measurements and presets needed!
Servo-reversing by holding sticks over on power-up, saved to EEPROM during power-off (throttle deliberately doesnt reverse in software, safety thing!)
Rates variable from 100% down to 10% via a pot, click for no rates
Expo variable from none to lots via a pot , click for no expo (thanks to Paul Luby for the expo maths!)
Single-handed range check mode, flick ch6 three times to invoke, throttle is held off, exit by moving stick
Switchable elevon mixer for flying-wings
No bootloader delay, instant ppm so Corona-safe!
 

 

PS   just got a copy of RCM&E, saw you in Alex's 'Weekenders' column, well done Paul, great to see this stuff getting a mention!

Edited By Phil Green on 24/07/2014 18:21:38

[GONZO]

Phil,

Thanks for the offer on the nano but I think I'll wait a bit longer. I've never had an order take so long, I think I feel a PayPal dispute coming on.

It doesn't look like a good time for me on orders. Having got enthused by all this I ordered a Hantek DSO5102P scope from the bay. Stock listed as in London. I've since had an email saying they made a mistake and its now coming from their German warehouse?????? We'll see, maybe another PayPal dispute if it doesn't arrive or its damaged.

[Paul Luby]

Gonzo

The Hantek I got off e-bay was listed as located in London and mine arrived within 72 hours of order with a German Postmark.

Paul

(AKA Veri-Gash)

[Paul Luby]

Hi Phil

Sorry its been a while, been laying a new kitchen floor and filling out all my BAE pre-employment stuff online.

The only time I bin the bootloader is if I need the memory space getting rid of it releases.

I tend to use another Arduino as the ISP programmer but thought I'd get up to date and buy a USBTinyISP adapter. I have a CH340G based Arduino Pro Mini programmer that I reckon I could use as an ISP programmer but its not on the Arduino IDE menu so I reckon that would be a headache waiting to happen.

The USBTinyISP is well known about so shouldn't have been any issue.

It worked on my 32 bit Win7/Linux dual boot laptop no probs using both Win7 and Linux.

On my Win 7 64 bit desktop (its a very powerful homebuilt affair) what a pain in the backside. It required multiple driver installs and reboots as well as driver info file replacements but all is up and running now. Problem is all the USB ports on my Asus motherboard are USB 3.0 and run extremely fast. On USB 3.0 there can be a timing issue with the USBTinyISP so the driver inf file has to tell the USB 3.0 port to slooooooow dooooooown a little.

All sorted now.

See what you mean about the boot up speed difference if you don't have a bootloader. Its not caused me any issues yet but it is worth keeping in mind.

But note, the Arduino Leonardo and Micro default to the sketch and only go to the bootloader if no sketch loaded. So if your using a Leonardo or Micro its not an issue.

I do tend to like the Micro cause it has 12 ADC inputs but they do cost a little more.

Anyhow, article stuff developing a little.

Paul

(AKA Veri-Gash)

[DJC]

hi all

came across another article about time it takes Arduino to boot up, their solution was to switch transmitter on first then receiver. this enable Arduino time to stabalise

djc

[DJC]

hi all

came across another article about time it takes Arduino to boot up, their solution was to switch transmitter on first then receiver. this enable Arduino time to stabalise

djc

[Phil Green]

Thats one way Dave but I wanted rid of it as it was messing up my 'sticks-held-over' reversing method which I've standardised on across the range.

Most modules dont mind power then ppm a couple of seconds later, but I have a few mates who use Corona and that strictly needs ppm at power-on. Quite why Corona defaults to 500uS pulses in the absence of ppm I dont know, but the couple of seconds of bootloader delay is enough to strip a full set of servos.

If you do want to re-use the board for something else its easy enough to put the bootloader back on.

Did you see Chrisie's post, she's done some pic programming, her view was arduinos are "annoyingly good..."

Done a bit more on mine, got the servo-slow on ch6 working (the toggle).  Think I might call it finished at that, although theres always another idea comes along when you least expect it  (ideas often wake me at 3 a.m!)

I electrickified my pushbike today, just been sailing around the village, weird sensation freewheeling uphill!

Cheese
Pies

Edited By Phil Green on 03/07/2014 00:20:17

[Paul Luby]

Hi Phil

"Annoyingly Good", I like that it describes them perfectly. As a development device on a PCB I think their very versatile. The fact that all you need is an Arduino, a USB cable and a PC makes them very accessible to many electronic/programming novices.

If you want to step it up to a whole new level then get one of these.

RIotBoard

It's basically a really powerful tablet without the tablet. Mine is hook up to a monitor and keyboard and I use it to test new Android App ideas I have.

I also have a couple of Raspberry Pi's kicking around but the RIotBoard beats them hands down.

Paul

(AKA Veri-Gash)

[GONZO]

Paul,

Well as you said the scope arrived today, just need to unpack and check. But, as you'll see on another thread looks like my nano's are still in Malaysia.

Phill,

What sparks for the bike? Hub or CD? Bafang BBS01(2) or GNG etc or home made?

[DG3]

Folks, as you know I used an old transmitter and converted it to a dumb buddy box with an arduino programmed to provide ppm out. It works fine when connected to the Taranis but not an old Spektrum DX6i. I am thinking that maybe the ppm signal needs to be inverted relative to the way I have it set up for the Taranis, i.e. initialisation pulse to be low for 300us then channel data to be high for the remainder. I don't own the Spektrum or have it nearby to try out.
This got me thinking about the requirements of the Spektrum trainer port, i.e. what does it expect in terms of voltage and signal specs (initialisation pulse length etc)? The Taranis worked perfect with 5V, 300us init pulse but I don't know the specs for its port also.

Any thoughts?