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PINNED - Plug & Play PGDT for Radio Control

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Re: Plug & Play PGDT R/C

Postby Burgerman » 09 Mar 2014, 00:38

OK. The black one is now zeroed, set up, has a slightly tighter deadband, and I soldered my 3mm jack plug on it!

So will send the white one back?

I will do a page update, and add that email, and a description. But no pics yet as I don't know how a finished "production" one will look?

I just sent my chair around the college grounds. Its about a half mile trip, and it works perfectly, stops if I turn off TX, steers correctly, and works better than my original analog one.

Seems to have no bugs or issues, so good to go. Its very odd that you can get full forwards AND full left for eg at the same time though. Its correct, but a mobility joystick doesn't allow it. I am going to modify my pilot plus one to allow corners... Like a RC TX. If I can find a way.
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Re: Plug & Play PGDT R/C

Postby woodygb » 09 Mar 2014, 01:02

Yes send the white one ...
I didn't have any more jack plugs kicking around....I'll need to purchase a few.

Its very odd that you can get full forwards AND full left for eg at the same time though. Its correct, but a mobility joystick doesn't allow it. I am going to modify my pilot plus one to allow corners... Like a RC TX. If I can find a way


Didn't your analog interface do the same "full forwards AND full left" as this Arduino based one?

I did note that I got a slightly different calibration result for the max / min numbers if I stirred the transmitter stick around whilst calibrating , as there is slightly more signal range across the corners... this resulted in a VERY slight loss of max speed / turn in the horizontal and vertical stick movement.... hence my instructions to calibrate by taking the sticks straight UP/DOWN and LEFT/RIGHT.
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Re: Plug & Play PGDT R/C

Postby Burgerman » 09 Mar 2014, 01:12

Didn't your analog interface do the same "full forwards AND full left" as this Arduino based one?


Probably but I set it to behave like it had "round" sticks as per helicopter cyclic commands about 10 years ago when I did it. Old 35mhz system. And cant say I tried it without. It digitally reduces throw as you go off axis on both channels. It thinks its a helicopter swash plate...

Its not to do with the interface, just the shape or amount of freedom the stick has.

On a powerchair as you turn "left" from full speed, you are FORCED to reduce the throttle as the stick goes left. In an extreme turn, to zero.

On a RC SQUARE stick (and no software to tell it to behave as a round stick) you can have full left AND full forwards.

I quite like it, it squeals the tyres and allows you to tear about in quite loony fashion! But control requires considerably more care/skill if you are to end up where you expected to go!
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Re: Plug & Play PGDT R/C

Postby woodygb » 09 Mar 2014, 01:16

I quite like it, it squeals the tyres and allows you to tear about in quite loony fashion!
:o I'd never have thought it of you! :shock: ... LOL. :lol:
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Re: Plug & Play PGDT R/C

Postby Burgerman » 09 Mar 2014, 01:24

You see normally, to go down a road, swerving side to side for eg, requires considerable left and right stick.

That PREVENTS you from having the stick fully forwards most of the time as the round motion requires you to pull the stick back as it goes sideways. The chair slows right down.

By RC with square stick, it slows a little (software?) but you can keep at 100 percent forwards stick as you swing left/right. Its lots faster while turning.

Round is easier or "better" and more intuitive, in enclosed spaces as you manoeuvre about. But its a hindrance if you want to say, keep fast as you turn into a driveway, or if you need a handful of turn stick to go straight along a road cambered edge. This now hardly slows down in such circumstances.

But in tight areas, you can accelerate too hard as you turn and wheelie yourself out sort of sideways tipping over on one rear wheel... Not very safe!
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Re: Plug & Play PGDT R/C

Postby woodygb » 09 Mar 2014, 01:42

By RC with square stick, it slows a little (software?)
..I didn't add anything clever to the software ( I did however add mixing to my Robot Arduino interface ) it merely takes the R/C signal and converts it to a voltage for the Omni.

Hmmm .. Just out of interest ... I'll plug in the white one when it returns and have a look at the numbers on screen whilst keeping the transmitter stick on full forward then sweeping across from left to right.
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Re: Plug & Play PGDT R/C

Postby Burgerman » 09 Mar 2014, 10:23

I suspect you will just have 2 linear unconnected outputs.

Its the fact that you cannot do exactly that with a wheelchairs physical joystick that is different. Its got no corners!
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Re: Plug & Play PGDT R/C

Postby LROBBINS » 09 Mar 2014, 12:05

John,

Is that because there's a round restrictor plate in the WC joystick? There are square ones available if you want to live dangerously, turn 45o if you want to live hyper-conservatively.

Ciao,
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Re: Plug & Play PGDT R/C

Postby Burgerman » 09 Mar 2014, 12:09

Is that because there's a round restrictor plate in the WC joystick?


Absolutely.

I don't know if I could live with it full time though...

Difference between driving by RC and Powerchair joystick is huge!
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Re: Plug & Play PGDT R/C

Postby woodygb » 09 Mar 2014, 12:12

Information post on the Spektrum receivers that I would consider suitable ..they also require no additional fiddling by the user setting failsafe positions.

Here's 3 that I have checked the specs on.

AR600 Failsafe
• Prevents unintentional electric motor response on start-up.
• Establishes low-throttle failsafe if the RF signal is lost.
• The AR600 removes servo output pulses to all channels except the throttle channel during failsafe.
• The AR600 throttle failsafe position is stored via the throttle stick position on the transmitter during binding.
HOW AR600 FAILSAFE WORKS
Receiver Power Only
• When the receiver only is turned on (no transmitter signal is present), the throttle channel has no output—to avoid operating or arming the electronic speed control.
• All other channels will have no output signal.

The following also have the same failsafe protocol.... there may well be more.
AR610
AR400
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Re: Plug & Play PGDT R/C

Postby woodygb » 09 Mar 2014, 12:20

Nothing wrong with some of the other receivers IF the user is familiar with R/C.

They do however require a modicum of knowledge to set the failsafe positions correctly.

The one below is however TOTALLY UNSUITABLE.

SmartSafe Failsafe
The AR6210 features SmartSafe failsafe. SmartSafe is ideal for most types of aircraft. With SmartSafe,
when signal is lost the throttle channel only is driven to its preset failsafe position (normally low
throttle) while all other channels hold last command.
• Prevents unintentional electric motor response on startup.
• Eliminates the possibility of over-driving servos on start-up by storing preset failsafe positions.
• Establishes low-throttle failsafe and maintains last-commanded control surface position if the RF
signal is lost.
Receiver Power Only
• When the receiver only is turned on (no transmitter signal is present), the throttle channel has no
output, to avoid operating or arming the electronic speed control.
• All other channels are driven to their preset failsafe positions set during binding.
Note: Some analog servos may coast slightly even though no signal is present. This is normal.
After Connection
• When the transmitter is turned on and after the receiver connects to the transmitter, normal control
of all channels occurs.
• After the system makes a connection, if loss of signal occurs SmartSafe drives the throttle servo
only to its preset failsafe position (low throttle) that was set during binding.
All other channels hold their last commanded position. When the signal is regained, the system
immediately (less than 4ms) regains control.
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Re: Plug & Play PGDT R/C

Postby Burgerman » 09 Mar 2014, 14:14

HOLD LAST COMMANDED POSITION (and throttle to idle) is what at least half of them do...

And the ones that do more (such as the AR1000 receiver that I use) do exactly this too. But they also have an additional OPTIONAL PRE-SET FAIL SAFE.

This sends all outputs to a position you choose, on loss of signal.
So you would just choose STOPPED or mid sticks, and throttle at zero.
Then on signal loss or if you switch off, the receiver stops everything and holds position.
This requires a different BIND procedure. Its easy to do.
This is what many of the better higher resolution and multiple satellite receivers do.
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Re: Plug & Play PGDT R/C

Postby woodygb » 09 Mar 2014, 14:30

Indeed ...I merely wanted to make people aware that certain receivers are dangerous to use for R/C control of wheelchairs .

Also ...that a plug and play type is available ...and depending on the aptitude of the user ...more advanced but programmable failsafe receivers are also to be found.
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Re: Plug & Play PGDT R/C

Postby Burgerman » 09 Mar 2014, 14:53

I will do a page listing the requirements. And also the other makes, such as Futaba, and about 6 or 7 others will need similar requirements. We are only talking about Spektrum so far. And JR in my case.


There is likely a big bunch of people that will want to be able to move a chair about by RC. There's one here http://www.wheelchairjunkie.com/forums/ ... #Post61768 for eg already.

But whatever you give them, however "plug and play" this new device you just built may be to some, it wont be for most!

Whilst its true you can just plug it in, and it will work, it needs at very least the following...

- ability to understand the way it works, so to get correct channels, and connections etc.
- ability to understand the differences between different manufacturers RC failsafe systems, and even differences within brands to be SAFE and to understand exactly how to set this up and TEST it...
- ability to understand the dangers of dead spots, range, etc. 1 second before failsafe can do a lot of damage or break someone's legs even if set up correctly to safely stop.
- ability to understand the calibration procedure of RC to YOUR device. It took me several goes to get true settings and true neutral setting - especially with cheap radios.
- ability to figure out how to correctly recalibrate the OMNI to your interface.
- the importance of the ORDER that you do this.
- ability to test all this to be sure its all set up perfectly.

This stuff is obvious to me, and you. But not to most people.

I suspect that if the guy in the post linked to above ever got it working at all, at least half of the above would be all incorrect. He wouldn't know the difference, his chair will end up half way across a motorway and one way or another it will be someone else's fault...

Its totally safe if you understand what you are doing. And the technology and how it works, if set up correctly.

But as my friend Trevor used to say - it doesn't matter how idiot proof I make things, they just keep on bringing out better idiots. So each one better include a disclaimer!
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Re: Plug & Play PGDT R/C

Postby woodygb » 09 Mar 2014, 16:16

That possibility had crossed my mind and I certainly couldn't entertain any legal action.

Thus I think an "AS-IS " disclaimer would probably be appropriate.

However, a seller can remove liability by informing the customer before the purchase that a product must be taken "as-is." This means that there might be faults with the products and the buyer has the opportunity to inspect the product and decide whether he really wants to buy it.


Together with something along these lines...

"In no event shall our company be liable for any direct, indirect, punitive, incidental, special consequential damages, to property or life, whatsoever arising out of or connected with the use or misuse of our products."
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Re: Plug & Play PGDT R/C

Postby Burgerman » 09 Mar 2014, 16:20

Swap company for "I" as an individual, and yes. For experimental and hobby use only, and all damages to people or property at the users own risk...

Because if I post that on a web page its there forever. Right next to the email address.
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Re: Plug & Play PGDT R/C

Postby woodygb » 09 Mar 2014, 16:50

Comments invited on this proposed disclaimer.

This product, and any other projects offered for sale in the future, are for experimental and hobby use only.
It is sold on the understanding that YOU the buyer must accept that it is sold "as-is" , thus YOU must take responsibilty for deciding on it's suitability for the use that YOU intend to put it to.
In no event shall I be liable for any direct, indirect, punitive, incidental, special consequential damages, to property or life, whatsoever arising out of or connected with the use or misuse of my products.
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Re: Plug & Play PGDT R/C

Postby Burgerman » 09 Mar 2014, 17:51

Sounds pretty good to me!

I will just add your email inviting sales, and can add that if you wish too. How much? Don't be too cheap. Theres work and time and postage involved.
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Re: Plug & Play PGDT R/C

Postby popschief » 09 Mar 2014, 19:14

Great project, good work Woody and BMan. Can't wait. This way I can bang into things around the house without turning my toes black & blue. :lol: The tight corners are already rounded off so no worries. :oops:
bp
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Re: Plug & Play PGDT R/C

Postby Burgerman » 09 Mar 2014, 19:58

Can anyone see that email addy that woody wanted me to use its lost without trace! I searched this thread 3 times!
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Re: Plug & Play PGDT R/C

Postby woodygb » 09 Mar 2014, 20:08

Weird !!..it appears to have disappeared :o .

woodygb@orangehome.co.uk

FOUND IT ..DIFFERENT THREAD

viewtopic.php?f=2&t=3955&p=51920&hilit=woodygb%40orangehome.co.uk#p51920
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Re: Plug & Play PGDT R/C

Postby Burgerman » 09 Mar 2014, 20:46

http://www.wheelchairdriver.com/radio-c ... rchair.htm

Well if anyone wants one they can email you to discuss it.

Disclaimer pretty obvious.

And you should copy and past it into your replies or emails should anyone order one.
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Re: Plug & Play PGDT R/C

Postby woodygb » 09 Mar 2014, 20:59

Cheers ..I suppose I'll need to price one up.
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Re: Plug & Play PGDT R/C

Postby mous3 » 11 Mar 2014, 00:48

I know you have Rnet and pilot+ working but could you do one for VR2 ? No rush I am using my old shop rider for learning and experimenting on I have fitted a flat top on the seat base mounts so it can carry things like my big rc helli for me. Would I need to get an Omni for you or could you get one?
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Re: Plug & Play PGDT R/C

Postby woodygb » 11 Mar 2014, 01:19

I'm sure that I could do a plug in one for a VR2 & the VSI joystick pod.... it'll just take a little time .
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Re: Plug & Play PGDT R/C

Postby mous3 » 11 Mar 2014, 22:22

Grate take your time cos my wheels are being a money pit
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Re: Plug & Play PGDT R/C

Postby woodygb » 11 Mar 2014, 22:29

I have sent you an email saying that I will need you to prod around in the VR2's pod with a multi meter.... let me know when you want to do some voltage readings.... I need to know if pin 7 on the VR2 circuit board is permanently live 5v+ ..if it's not ...see if you can find any convenient permanent live feed in the pod.

mouse vr2.jpg
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Re: Plug & Play PGDT R/C

Postby woodygb » 17 Mar 2014, 10:36

Finalised build size.

003F.jpg
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Re: Plug & Play PGDT R/C

Postby woodygb » 17 Mar 2014, 10:46

.
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Re: Plug & Play PGDT R/C

Postby Burgerman » 17 Mar 2014, 11:25

Your eyes are way better than mine! :o
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