Arduino controlled wheelchair

[gcebiker]

Sweet,

This is a micro update to the last one, removed the unnecessary via's i put in by mistake under the DG419 and Cap
Updated the description at the bottom.

Arduino_Shark_BRD_v1.9.zip

(12.58 KiB) Downloaded 467 times

Arduino_Shark_SCH_v1.9.zip

(8.3 KiB) Downloaded 493 times

[sirmike]

As to the choice of Pi I'd go with a model 3B as it gives the best bang for the buck just now... best deals are in Aliexpress..

$37.66USD with free shipping
https://www.aliexpress.com/item/2016-Ne ... a0d022b55b

Also worth buying the heat sinks... dirt cheap and cheap insurance for longevity..

$2.03USD plus free shipping
https://www.aliexpress.com/item/1-Set-o ... a5e639b05c


Use a Plastic case if you want to use the built in WIFI and Bluetooth that come on the 3B.

Now a word on cases... and HATS..

the standard HAT profile is... 65 x 56.5mm while the Pi board itself is 85 x 56.5mm
in order to have lots of proto space I propose going with HAT mounting points and Pi board dimensions..
the cost to produce is boards is the same, but there is a trade off here... this means using a taller header
and nylon spacers to get above the USB and Ethernet connectors on the Pi board.. (they're available),
and the tidy case you posted with room for a HAT board would not be tall enough.. meaning the need
for a larger case for the PI... use a plastic sandwich case or some such..

[sirmike]

Pis use SD cards for their OS and "hard drive"storage so buy a decent 16 or 32GB Class 10 card to do along with..
http://www.megabuy.com.au/samsung-evo-1 ... 65892.html

You'll need a usb keyboard, mouse, and HDMI cable and TV/monitor with the right input..

Also a power cable USB to micro USB and a phone charger with an min of 1A preferably 2.1A output..

$1.75 USD free shipping
https://www.aliexpress.com/item/Raspber ... ec0d6d0388

$1.95 AUD
http://www.megabuy.com.au/rc-hdmi-oem-h ... 15898.html

$9.79 AUD
http://www.ebay.com.au/itm/4-Ports-USB- ... 2986505318

[gcebiker]

I really like the idea of having a nice case to put the Pi in...not sure where the A,B leads would go.

So might have to forgo putting an OLED screen in eventually ?

As we have done (well you did most of it) would you be able to finish off the Arduino Board itself ?

I would like to have something basic and cheap as eventually i will be using this to tow my boat to the water and leave it there, should it be stolen/vandalized/corroded/driven into the water .... cheaper is better if i have to replace it.

Whats your thoughts on the Pi Zero ?

Possibly use it in place of the Arduino Nano ?

[gcebiker]

Those Pi's are not cheap here in Australia $50.42 ....especially when i have nearly every recent Arduino in the shed already, plus the Arduino Nano is only $15 ive quite a few AT Tiny85 Pros here too, i was thinking when i got them that i could make small shields like they have and fit it inside the Receiver case for Nintendo Wii.

I think lets make the Arduino board first then move onto the Pi stuff when we have tested em ?
Making the Arduino board now able to fit the Pi does make good sense though.

Ill order my own board once we get them done with DirtyPCB, cheaper than post between countries, Australian postage is nuts.
I guess cause we are in the middle of nowhere...

[sirmike]

OK here's the HAT via email.. look it over and see if you see any flaws in the connections.
I will do the same after a good nights rest then I think it is ready to go..

[sirmike]

I can do up the v1.9 board tomorrow if this doesn't suit..

[sirmike]

Also if you want to do the V1.9 what final dimensions do you want for the board.. needs an outline drawn in, etc..

[gcebiker]

Gave it my best shot for tonight, its 1am and i should get some sleep.

I dont like the auto router, so the board tracks need a tidy up i feel but its only cosmetic.

Here it is for anyone following.

For testing this should suffice Mike, the Pi connections should not impact on it being used as a stand alone board.
I will error check it tomorrow, i know for sure some of the rat nest wires are missing, i did not know i needed them, i put them in tonight for new connections but they are probably missing for the old connections from the cut/paste job i did.

I also put the Power Resistor in at the near the right size and also the 6v 1000uf cap on the Traco, tho we don't need it for the Arduino we might need it for add on stuff later.

[sirmike]

ok ready for review.. cleaned up traces that the autorouter got messy with, checked traces against the schematic, labelled parts..
beefed up the trace size where possible for better current handling.. looks pretty clean now.. I'm happy with it, what do you think?
Time for the board house?

incoming in via email.

[sirmike]

For you reference, each plotted layer of the board required a Gerber Plot file.
Some board houses will accept Eagle.brd files and will generate gerber files for you, some will not.

I took a run at generating the gerber files then viewed the resulting plot files with View Plot from http://www.viewplot.com/
Each layer looks good.

A plot file is generated for each part of a cct board and the details are fed to a CAM processor that creates the plot files.
It is important to have only the relevant layers turned on to generate each plot file.. i this case I used:

Plot file Layers
------------------------------
TOP_PCB 1,17,18
BOTTOM_PCB 16,17,18
DRILL_ROUTE 20,44,45
SILK_TOP 21,25,27,51
SILK_BOTTOM 22,26,52
MASK_TOP 29
MASK_BOTTOM 30

Dry run worked ok.. so now it's up to you on how and when you want to proceed.

[gcebiker]

Just sent email, there were a few changes needed, i made some mistakes late last night

I got up to Ver 1.8, allows for both board to be made with out having to redesign it radically.

Pi version should fit into a Pi box ?

Arduino only version should fit into that case i linked you, with room in the corners of the board to mount it ?
https://www.jaycar.com.au/jiffy-box-black-83-x-54-x-31mm-bulkhead-ub5/p/HB6016
With room for the RC receiver on top.

[gcebiker]

Ver 1.9 i have also emailed you ,..well i forgot then i remembered..
My traces might need thickening up a bit.

Oh 84.96 is fixed length hey because its a Hat, forget that request.

[gcebiker]

If anyone wants a stand alone board, i don't have the .sch file.
Mike and I are going to order some of the boards above, slightly tweaked. We'll report back.

Ill be making this board as small as i can and also one to go with a Pro Mini if i get time.

[gcebiker]

Boards on order from DirtyPCBs.com
Mike has done the Pi bits and checked all my prototypes...21 different board designs..and sorted the Gerber files for me...Thank you Mike, I did the Shark EMU bits in the middle.

Its been a long road but nearly there and with the added functionality of the Pi we can do more stuff

[gcebiker]

More tinkering, will test the boards on order before finishing tweaks on the stand alone version.
This board will be able to interface with (Nintendo Wii, RC receiver, or Analog input) with the appropriate code applied to the Arduino Nano V3.0

Code is listed though out this thread but after the board has been tested a bit more, i will post with all versions of the code and links to order the board from dirtypcb.com . Ive a brain injury myself, use this stuff at your own risk after evaluating it for your needs.

[gcebiker]

Ver 1.2

- Tried to make it more compact
- Making more room for data/power wires

Will still need size adjustments (possibly) to fit into off the shelf boxes, ill test space with physical box by Wednesday.
/opps just noticed i have forgotten the wire to 24+ from D1

[gcebiker]

Dynamic Shark Emulator board will now fit in the off the shelf jiffy box from Jaycar.

...only just, can someone with board making experience please have a look over this, i am worried my traces go to close to the edge of the board.
I'm also worried the mounting holes have a minimum distance from the edge ?

I will be able to fit 2 of these side by side on a 10cm + 10cm prototype board, just need to watch a few videos to learn how to do that bit.

This picture is the wiring diagram and colours that Dynamic use for the Shark Bus Differential Serial RS485 cable.

This is a picture of the proposed PCB board, i would like feedback please, if you have any.

The serial outputs are labeled A/B Blue/Yellow
The output pins from the MAX485 and the corresponding colours on the Shark Bus cable if you chop one up.

The picture is in High Res , it may be necessary to download it to see the traces clearly.

Pin outs for both chips

[gcebiker]

Boards came in the mail this morning.

- First thoughts
The model i used for the pin header on the input/output seem to have very big holes.

The Eagle program is really to scale !
Traces/pads everything , so i know i need to do a version 2.

I will populate today if brains allow it, they are doing renovations next door and noise plays havoc with ...well everything.
At the very least i will try to get the parts dry mounted.

Cheers
Tony

[gcebiker]

It WORKS !!!!

Top - PCB No.2
Lower - Board House PCB Ver 2.1 (which has some minor issues - listed below)

Pre-Arduino, all lower components fitted...there are not many needed

Post-Arduino

My Arduino Code is here, viewtopic.php?f=2&t=4867&start=520#p105147

--- Minor things that need fixing for next version.
- Holes for header pins are way too big, makes soldering and keeping them straight a little interesting.
- Holes for 1W 1K Power Resistor are too close together and also too big.
- Labeling on Silk Screen for A/B is way out of alignment...to the point where you wont see B and put A into 'Bs' hole, no pun intended.
- If i had space and i think i do. I would leave a place to zip tie the RC Receiver in place.
- Possibly not populate so many +/Gnd pins, to easy to bend and short it out.

I know nothing about Pi connections so i will leave that testing to Mike.

But the board works as it is, just that soldering is a little tricky if you populate all of the three rows of header pins.
If you only solder the 5 needed its much easier.

[ex-Gooserider]

Look at the documentation for the board house you are using - most SHOULD have specification pages with things like minimum track sizes, spacing and things like clearance between tracks and board edges / holes... These are usually relatively consistent, but will vary slightly between board houses so you should use the one you work with as the final say... If you can't find a spec page, you could at least start with the one that OSH-Park (one of the preferred small run board houses in the US) uses.

Thru-Holes are tricky on boards, as you have to account not just for the diameter of the hole, but how much it will be reduced by the copper plating in the hole... Again this can be something to ask the board house about, as they may have better data about what you should use for plating allowances...

The other factor that can bite you is the exact dimensions of the ACTUAL parts you are using - if at all possible get the data-sheet and drawings for the actual part you are ordering, don't just use the 'generic' sizing... It is even better if you can actually get the part physically in hand, and make your own measurements....

Only downside of making your own measurements to get more precise holes is that you are then 'married' to that part, and if it changes or you go to a different supplier on the next batch, you might need to re-do the board to fit... It's a trade-off.

One of the ironic things about the big-money professional board design packages is that they all brag about their 'part libraries' - but the advice of the professional designers I know is to ignore the libraries, and work ONLY from the parts that you physically have in hand, and have personally measured (using library stuff might be OK after verifying the measurements).... They argue that this is painful, but far less so than explaining to the boss about why the board they just ordered several thousand of doesn't work.....

ex-Gooserider

[sirmike]

Looks cool..never seen a yellow board in production.. I've ordered some 2A Traco parts in anticipation of running a pi + nano off of the chair supply..

[gcebiker]

One of the ironic things about the big-money professional board design packages is that they all brag about their 'part libraries' - but the advice of the professional designers I know is to ignore the libraries, and work ONLY from the parts that you physically have in hand, and have personally measured (using library stuff might be OK after verifying the measurements).... They argue that this is painful, but far less so than explaining to the boss about why the board they just ordered several thousand of doesn't work.....

ex-Gooserider

Yes this is what i have started doing, having the actual boards in front of me now i can see that the large holes on the pin headers are also on the Eagle drawings.

I am in the process of doing just as you say, measuring the part and finding something in their native library that is the same pin size and length/width.

Its been an awesome learning experience, for the $50 they were to get to me i am very pleased it worked first go.

[gcebiker]

V3.15 Arduino Dynamic Shark Emulator , Pi Hat on order.

- Moved terminating resistor and cap around a bit.
- Corrected sizing / part for pin headers
- Corrected labeling on Input/output
- Correct part for the Power resistor and holes size
- More room for Power regulator, i am not sure what size Mikes 2Amp one is...and not sure that 2Amps will be enough to run the Pi and the Hat.

... Made it Blue

WoW this is a long way from where it all started and a few $$ along the way.

[gcebiker]

Ok, you might not be able to pick them but there are a lot of changes ...to the labeling.

Tho they say "Renderings are for reference only" ...na they are pretty spot on, but nothing close to the spacing you use in Eagle CAD.

Sooo after many versions and re uploads to check the changes, this is what it looks like now.

Tidier... a bit OCD but if its worth doing, its worth doing right ! ...eventually
Small mercy that the board house had the day off and i had time to re upload each iteration as i double checked the silkscreen.

[ex-Gooserider]

One of the things I've seen suggested as a 'sanity check' is that there are many free software Gerber viewer programs out there - some are part of other packages like KiCad, and there are a few that are more stand alone... The suggestion is to look at the Gerbers from whatever package you are using for the board design in the viewer from some OTHER package and make sure everything still looks OK....

The idea is that this helps spot any glitches that were hidden by bugs in the package that created the source files.... Essentially it's a variation on the 'get a second set of eyes' to check things...

ex-Gooserider

[gcebiker]

Blue boards came today, had some weird results.

I've just found, I forgot to run a trace to the 5v in for the Arduino...no biggie, ill add a jumper tomorrow and retest.

[gcebiker]

Yellow and Blue boards work great !
Radio Control - Arduino Shark Bus Emulator for the Dynamic Shark Power Wheelchair Controller

Blue boards work great...once i put the jumper in.

I have 18 spare boards, 9 of the Yellow and 9 of the Blue.

Anyone in Australia Wanting one, partially populated (resistors, IC sockets), i wont be able to post with the caps soldered in but will include them in the parcel.
$25 delivered with signature - Australia Only


Yellow have the larger holes on the input / output sides of the Arduino, larger holes for power resistor.

Blue is better laid out, corrected hole sizes, i will put the wire link in as well as the other minor components for anyone wanting one.

I have enough components to fully build up and test 5 Blue Boards if anyone wants a completed version, you will have to supply your own RC unit and wiring.
P.O.A

Posting to Overseas....OMG, From Australia...postage its expensive, on the upside, our Dollar is rubbish...so its like 75% off , prices i have listed are in AUD.
Probably still cheaper to just order 10 from DirtyPCB

Next version (not available as yet, till testing can be done on the Raspberry Pi Sections SirMike is interested in/requested)
Ver 3.25 has the power to the Arduino fixed, a link/place for putting a switch should you want to leave it connected but turned off.

Amendments to the code would also enable this to remain connected and able to remotely turn the Radio Control Sections On/Off the same as Woodys JC2000 Joystick RC Arduino Bluetooth Smart Phone Version is able to do for the VSI style joysticks or if you prefer the WJJRCABS, maybe one of you military types might be able to come up with a harder to remember acronym ?

[societypeople]

Hey gcebiker and sirmike, Hope you both are well! I just wanted to say thanks for the work you've put into this project. A friend and I have recently started working on a Pronto chair to use as a robotic platform that seems to use the same dynamic shark motor controller and rs485 serial communication protocol. It looks like you've already done a lot of the heavy lifting figuring out the protocol and we were wondering if we could use your help replicating your hardware design since ours has had some issues. We've been able to wire the Arduino, max485 and dg419 chips in-line with the current joystick and make the brakes release, but have not been able to get the startup pulse correct. Would you be willing to email use the eagle cad files you have so we can check where we went wrong when you have a chance? if you'd prefer emailing them, my address is zappy@bitgel.com

We also be happy to help with the raspberry pi addition sirmike seems to be suggesting if desired. We've built a previous platform using a raspberry pi and xbox controller similar to what sirmike seems to be doing, but just hacking into the analog joystick instead of the serial data lines. Most of our code for that raspberry pi is written in python and then communicates commands to the Arduino over a serial line, but we'd be happy to share it if it'd be any help at all.

Here's a video of our previous platform during some of our testing:
https://youtu.be/8ZYs1K1X-EY

Thanks!

[gcebiker]

Would you be willing to email use the eagle cad files you have so we can check where we went wrong when you have a chance?

Thanks!

The "schematics" and code is listed in this thread.

I don't intend to post the Eagle files, i will however share the Dirty PCB link to reorder when i get back from walking the dog.

'Most of the heavy lifting' , It's ALL been done