WillChair 2 Build Page 3

You're still following along.  Impressive.

There were no suitable joystick housings to be found.  I came across a few that would have worked ok and gotten the job done, but like the rest of the chair, why settle for something universal because it would get by acceptably when you can make it function properly?

This on the left was extruded from a semi flexible PLA based filament.  It has the consistency of firm rubber that's not quite as stiff as car tires.  The housing this goes onto is made from a very hard plastic.  This stretches and snaps onto it.  No screws required.  The switches shown were just for test fitting.  Note that the joystick is a swing-away type.  The aluminum knob (which will later be coated, trimmed shorter, and engraved) adjusts the tension required to swing it in or out.

Short video of the joystick housing being made

Not much detail needed.  This is the footrest and mount for it coming together as well as the tilt actuator mount.

A little metallic blue makeup never hurt anybody

The hubcaps.  I guess that's what you would call them.

Short video engraving it on the little CNC machine I built.  Yes, it's going slow.  The little feller can only get to 2500 RPMs on the spindle.  More like 20,000 is needed.  And yes, that's a center drill.  They engrave a better fat line than a dedicated engraver bit.

These were rather tedious to get right.  I'm no pipe fitter/welder.  The armrests mount on here.

3d printed the mount.  I later whittled these out of A36 steel.

A coating of foo foo prettiness later and everything fits perfect. 

The telescoping rods are adjustable and set the armrests angle

Let there be light!  These are literally motorcycle headlights.  Overkill.  But eh, I've always got a pair of spotlights handy!  The mount is 3d printed.  The hole in the housing will go on bottom to let out any impeding water.  There's also a small pair of "cateye" type LED's on either side that aim left/right to light up an entire room or shine under a desk.

Now the fun part:  Electrickery!  I'm no electromagician or electronics engineer.  Everything was self taught and learn as I went on this first WillChair build.  Some went right the first try.  Some required releasing the magic smoke to figure out.  Everything went pretty much smooth on this build since I pretty much knew what I was doing and drew proper schematics beforehand.  Still a bit tricky dealing with three different voltages (5, 12, and 48v) with common grounds and isolated signal wires.  I won't go into much detail since I already did on the link above.

While the LiFePo4 chemistry these cells are based on is quite safe (IMO safer than the Pb battery in your car) the entire sides of the configuration is hot.  See some ends are red and some black?  Yeah, don't touch those together!  It turns into a welding machine.  Much respect and care is needed during assembly.

This is the charge and balance connector.  Good for up to 40amps continuous charging.  Max it will be used is 10 amps.  It only connects one way.  All of those wires have to be in the correct order for the charger to read each individual parallel cell group.  Getting one in the wrong spot will release the soul from the delicate balance circuit in the charger with a quick puff of smoke.  Been there.  Done that.  Got the charger/paperweight as proof.

The female end on the battery that connects to the one above.  More tedious soldering.  Color coded by the wires I had on hand to separate cells 1 through 7 and 8 through 14.

How to cram 10 pounds of very hot crap into a 5 pound bag in 3... 2..... 1........

You definitely don't want to drop a wrench in the battery compartment.  Fireworks!  The two silver boxes on the left are 48v to 12v converters.  They're rated for 10 amps each.  I tested a different brand and couldn't get over 7 amps from them.  Good ole Chinese specifications.  I never tested these to see their max output.  I went ahead and connected two in parallel for good measure and redundancy in case one fails.  I SHOULD never need over 10 amps from the 12v circuit, which is 10 amp fused anyway.

The blue box is a Roboteq robotics controller which was never meant for a powerchair.  It does allow running custom scripts written in Micro Basic, which opens up a whole new world of possibility.  I won't go into much detail here because I already have over here.

Quite a few more goodies get crammed in there.  The yellow plate was made for test fitment.  A stealthy black one was printed for use.  A pair of 12v DPDT relays on DIN rail mounts fit upside down on the bottom of that plate as well as a 260amp solid state relay that can be tripped on/off by a 12v switch. 

Much credit to my better 3/4 for the wiring and soldering.  After all of my projects she's been drug into she pretty much has her black belt in wire jitsu.

One final thing that was added last were two docking pins.  I use a custom built docking system in my car that I designed and built because nothing acceptable is available to buy.  This doesn't affect the chair's ground clearance or performance in any way, unlike any system you buy.

The quickest way to make a 1" fine thread nut 3/8" thick. 

The proper sized grade 8 bolt to start out with proved elusive.  So, I made them from scratch from a short length of scrap 304L stainless round bar.  I threaded each side to length.  It will later be split in the middle.  Much easier to hold this way and less scrap.

The smoothed area is where hooks latch on

Whacked off and ready for head

Press on and apply heat liberally.

TIG welded VERY hot

Return to the lathe to get trued back up.

That's just beautiful

No sign that this started out as two pieces

The aluminum trailer I built for her.  She gets worked hard and earns her keep.

Don't let the flood stop you.  5" deep water is no issue with a little application of common sense.

There you have it.  That's the Cliff's Notes version of building a better powerchair.  Thanks for your interest.  Feel free to leave me a comment or email me.  Links at the bottom of the first page.

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