[chbot] Home Automation - Curtains

Tue Sep 26 23:00:08 BST 2017

Thanks Carl.

I've had success with the builder's line.  I made a small loop in the
middle of the line for one curtain, and a loop at each end.  The cord is
wrapped once around the pulley (a 16T GT2 pulley) and the whole thing is
tightened by a zip tie that goes through the loops at the ends.  I closed
the gap from about 10cm to 1cm, which makes the cord very tight.

Now I can open and close the curtains using a switch.  The pulley slips at
the extreme end of travel, which is fine, although I might use a larger
diameter pulley so that there is more surface area in contact with the cord.

To automate it I will use an ESP8266 running microPython, and either a
motor driver board or a pair of relays.

Andrew

On Sep 26, 2017 10:13 PM, "Carl Ranson" <carl.ranson at gmail.com> wrote:

You might find that's not enough torque, depending on how the blind is
weighted, but as they say. your mileage may vary.

I've messaged my guy to see if he has an email with the specs for the one
we used.

3d printers are awesome. you'll enjoy it a lot.  I recommend learning
freecad for software. Really good cos you can link all the dimensions back
to a spreadsheet and then tweak the numbers if you need to make adjustments.

cheers,
CR

On 26/09/2017 9:27 AM, Andrew Errington wrote:

Hi Carl,

Nice to hear from you.  Glad you're still hacking on stuff.

I'm using this motor:
http://www.dx.com/p/diy-37mm-high-torque-silent-60rpm-12v-dc
-precision-gear-motor-grey-383488

It's pretty grunty, but 60rpm is a bit sedate.  Banggood have an 80rpm
variant and a 130rpm one.  They fit nicely onto the smallest purlin
bracket, which I've bolted to the wall with timber cladding screws.

Once I have one working I can buy six sets of parts for the windows in the
lounge.

I have also just bought a 3D printer.  It should arrive tomorrow so for the
benefit of everyone else reading this I'll start a new thread then
(assuming it's not a dud).

Best wishes,

Andrew

On Sep 25, 2017 9:57 PM, "Carl Ranson" <carl.ranson at gmail.com> wrote:

Hey Andrew,

been a while.

I actually did this for a blind in my house this year.
I had a friend building a house who wanted to do 18 of them (yes, 18!). Not
wanting to pay $400 each he sourced the motors from China for about 50
bucks a piece. These came with a remote control and settable limits etc and
they mount inside the blind itself.

Problem was, they didn't have attachment hardware. In comes the 3d printer.
problem solved and I got a motor for mine as payment.

Before that I'd tried door window motor with extra gearing. even that
didn't have enough oomph to draw the blind (although I probably could have
added weight to balance it a bit).

Hope that helps.
CR

On 25/09/2017 5:38 PM, Andrew Errington wrote:

There's also "fishing line I happen to have to hand", which is clearly
unsuitable in this case.

I'm going to try the builder's line again.  This time with a cable tie that
I can crank down on to get the tension.

Thanks,

Andrew

On Sep 25, 2017 5:01 PM, "Charles Manning" <cdhmanning at gmail.com> wrote:

There's fishing line... and fishing line.

Nylon stretches like anything. Braid (eg. https://www.completeangler.co.
nz/line-95/braid-97/) has practically no stretch and is available in many
colours and strengths.

On Mon, Sep 25, 2017 at 3:51 PM, Andrew Errington <erringtona at gmail.com>
wrote:

> Hi everyone,
>
> I thought I'd start a new thread, as we got away from the relative merits
> of Banggood vs DealExtreme.
>
> I am trying to motorise my curtains, particularly as there are six windows
> in one room, plus home automation is cool.
>
> So far I have identified a suitable motor and gearbox, 12Vdc supply, 60rpm
> output, with good torque and fairly quiet.
>
> At one end the motor, with a 16-tooth GT2 pulley, is attached to the wall
> using a purlin bracket (purlin brackets are cool).  At the other, I am
> using a sewing-machine bobbin on an M6 bolt as a pulley.
>
> It's early days, but I have tried builder's line, which doesn't stretch,
> but does slip.  I have tried fishing line, which does stretch, and slips.
>
> I think GT2 toothed belt would work well, but I haven't tried it yet.
>
> The motor is temporarily connected to a 12V battery for testing.  Later I
> will use an ESP8266 with microPython to control the motor.
>
> Finally, I'll link it to home automation software and relax in my chair as
> the sun goes down and the curtains gently and quietly close.
>
> That's my plan, but there is plenty of room for alternatives or failure.
>
> The attached link is for a belt clamp and tensioner made from zip-ties,
> which I think I will adopt!
>
> Best wishes,
>
> Andrew
>
> http://diyprojects.eu/wp-content/uploads/2017/01/belt-connec
> tion-zip-ties.jpg
>
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