<div dir="auto"><div>Thanks Carl.<div dir="auto"><br></div><div dir="auto">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.</div><div dir="auto"><br></div><div dir="auto">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.</div><div dir="auto"><br></div><div dir="auto">To automate it I will use an ESP8266 running microPython, and either a motor driver board or a pair of relays.</div><div dir="auto"><br></div><div dir="auto">Andrew</div><br><div class="gmail_extra"><br><div class="gmail_quote">On Sep 26, 2017 10:13 PM, "Carl Ranson" <<a href="mailto:carl.ranson@gmail.com">carl.ranson@gmail.com</a>> wrote:<br type="attribution"><blockquote class="quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div class="m_1671986269823556113moz-cite-prefix"><br>
You might find that's not enough torque, depending on how the
blind is weighted, but as they say. your mileage may vary. <br>
<br>
I've messaged my guy to see if he has an email with the specs for
the one we used. <br>
<br>
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.<br>
<br>
cheers, <br>
CR <br><div class="elided-text">
<br>
On 26/09/2017 9:27 AM, Andrew Errington wrote:<br>
</div></div><div class="elided-text">
<blockquote type="cite">
<div dir="auto">Hi Carl,
<div dir="auto"><br>
</div>
<div dir="auto">Nice to hear from you. Glad you're still
hacking on stuff.</div>
<div dir="auto"><br>
</div>
<div dir="auto">I'm using this motor:</div>
<div dir="auto"><a href="http://www.dx.com/p/diy-37mm-high-torque-silent-60rpm-12v-dc-precision-gear-motor-grey-383488" target="_blank">http://www.dx.com/p/diy-37mm-h<wbr>igh-torque-silent-60rpm-12v-dc<wbr>-precision-gear-motor-grey-383<wbr>488</a><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto">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.</div>
<div dir="auto"><br>
</div>
<div dir="auto">Once I have one working I can buy six sets of
parts for the windows in the lounge.</div>
<div dir="auto"><br>
</div>
<div dir="auto">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).</div>
<div dir="auto"><br>
</div>
<div dir="auto">Best wishes,</div>
<div dir="auto"><br>
</div>
<div dir="auto">Andrew</div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div class="gmail_extra" dir="auto"><br>
<div class="gmail_quote">On Sep 25, 2017 9:57 PM, "Carl
Ranson" <<a href="mailto:carl.ranson@gmail.com" target="_blank">carl.ranson@gmail.com</a>>
wrote:<br type="attribution">
<blockquote class="m_1671986269823556113m_-8894338939417272735quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div class="m_1671986269823556113m_-8894338939417272735m_-6158507875113516016moz-cite-prefix"><br>
Hey Andrew, <br>
<br>
been a while. <br>
<br>
I actually did this for a blind in my house this year.
<br>
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. <br>
<br>
Problem was, they didn't have attachment hardware. In
comes the 3d printer. problem solved and I got a motor
for mine as payment. <br>
<br>
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). <br>
<br>
Hope that helps. <br>
<font color="#888888"> CR</font>
<div class="m_1671986269823556113m_-8894338939417272735elided-text"><br>
<br>
<br>
<br>
On 25/09/2017 5:38 PM, Andrew Errington wrote:<br>
</div>
</div>
<div class="m_1671986269823556113m_-8894338939417272735elided-text">
<blockquote type="cite">
<div dir="auto">
<div>There's also "fishing line I happen to have
to hand", which is clearly unsuitable in this
case.
<div dir="auto"><br>
</div>
<div dir="auto">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.</div>
<div dir="auto"><br>
</div>
<div dir="auto">Thanks,</div>
<div dir="auto"><br>
</div>
<div dir="auto">Andrew</div>
<br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sep 25, 2017 5:01
PM, "Charles Manning" <<a href="mailto:cdhmanning@gmail.com" target="_blank">cdhmanning@gmail.com</a>>
wrote:<br type="attribution">
<blockquote class="m_1671986269823556113m_-8894338939417272735m_-6158507875113516016quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>There's fishing line... and fishing
line.<br>
<br>
</div>
Nylon stretches like anything. Braid
(eg. <a href="https://www.completeangler.co.nz/line-95/braid-97/" target="_blank">https://www.completeangler.co.<wbr>nz/line-95/braid-97/</a>)
has practically no stretch and is
available in many colours and strengths.<br>
<br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">
<div class="m_1671986269823556113m_-8894338939417272735m_-6158507875113516016elided-text">On
Mon, Sep 25, 2017 at 3:51 PM, Andrew
Errington <span dir="ltr"><<a href="mailto:erringtona@gmail.com" target="_blank">erringtona@gmail.com</a>></span>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="m_1671986269823556113m_-8894338939417272735m_-6158507875113516016elided-text">
<div dir="auto">Hi everyone,
<div dir="auto"><br>
</div>
<div dir="auto">I thought I'd
start a new thread, as we got
away from the relative merits
of Banggood vs DealExtreme.</div>
<div dir="auto"><br>
</div>
<div dir="auto">I am trying to
motorise my curtains,
particularly as there are six
windows in one room, plus home
automation is cool.</div>
<div dir="auto"><br>
</div>
<div dir="auto">So far I have
identified a suitable motor
and gearbox, 12Vdc supply,
60rpm output, with good torque
and fairly quiet.</div>
<div dir="auto"><br>
</div>
<div dir="auto">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.</div>
<div dir="auto"><br>
</div>
<div dir="auto">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.</div>
<div dir="auto"><br>
</div>
<div dir="auto">I think GT2
toothed belt would work well,
but I haven't tried it yet.</div>
<div dir="auto"><br>
</div>
<div dir="auto">The motor is
temporarily connected to a 12V
battery for testing. Later I
will use an ESP8266 with
microPython to control the
motor.</div>
<div dir="auto"><br>
</div>
<div dir="auto">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.</div>
<div dir="auto"><br>
</div>
<div dir="auto">That's my plan,
but there is plenty of room
for alternatives or failure.</div>
<div dir="auto"><br>
</div>
<div dir="auto">The attached
link is for a belt clamp and
tensioner made from zip-ties,
which I think I will adopt!</div>
<div dir="auto"><br>
</div>
<div dir="auto">Best wishes,</div>
<div dir="auto"><br>
</div>
<div dir="auto">Andrew</div>
<div dir="auto"><br>
</div>
<div dir="auto"><a href="http://diyprojects.eu/wp-content/uploads/2017/01/belt-connection-zip-ties.jpg" target="_blank">http://diyprojects.eu/wp-conte<wbr>nt/uploads/2017/01/belt-connec<wbr>tion-zip-ties.jpg</a><br>
</div>
</div>
<br>
</div>
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