Use tf tap changing or V regging, not series r, to adjust motor speed. Series R will greatly reduce peak torque.
This circuit will either fry the motor or pop the fuse the first time the motor stalls. Foldback current limit would solve that.
I'd add a 3rd central position to the switch so they can be stopped in places other than the endstops.
What about the mechanics? Any smart ideas?
NT
Simple reversible motor control circuit for curtains (drapes) (AGvdBerg 2005-05-26)
I searched for simple circuits but could not find any so I decided to post these, as there seem to be lots of interest.
These are very simple circuits that do not require extra electronic components such as gates, timers, transistors and smoothing capacitors or regulators. However nothing prevents one from enhancing the circuits by adding remote control and PWM (Pulse Width Modulation) to the basic circuits below.
Circuit 1: Curtain (Drape) motor direction control with automatic stop
Stop1 Stop2 Open & Close can be substituted Left || Right for Left & Right / \\ /\\ Transformer / | | \\ |--------+------------| |--+-o |-+---------+-| \\-+--| |--| | | DPDT | | | | | | | --- | | | | SW1a | | +--|>|--+ +--|
My curtain controller has been working fine for nearly a year now. I'd probably change quite a few things if I built another, but FWIW here is a photo of its mechanics:
The motor on the left is a geared type from a screwdriver, originally powered by 2 C-type NiCads. To its right is an improvised capstan I made from a plastic drum (I think an ex pill case), capped by soft wood end pieces. Into the left end piece I epoxy glued the screwdriver bit, for attachment to the motor spindle. To the right of the capstan is a crude bearing to maintain the capstan's horizontal axis, and to prevent the bit slipping out of the motor.
The two vertical nylon cords visible are the curtain 'pull cords'. I thought it would help to insert the elastic you can see here, but now I don't think this is true. I've recently removed one of the two sections of elastic, and would remove the other if I'd left enough cord!
The cord is secured to the capstan symmetrically, (by passing it through a hole in the drum, and 'pinning' it inside). It's similar in principle to the cord and drum used to tune old radios (an idea suggested to me here, about a year ago).
The two microswitches ensure the motor stops at its two extremes. You can just see the markings 'OS' and 'CS', meaning Open Stop and Close Stop respectively. So, for example, when the curtain reaches its fully open position, normally open switch 'OS' is closed, and the circuitry removes power from the motor.
Circuit diagrams are here:
There's a related discussion at present (about slowing down this sort of motor while maintaining adequate torque) in the thread Subject: Simple 555 PWM - disappointing performance Date: Tue, 24 May 2005 23:44:06 +0100 Message-ID:
-- Terry Pinnell Hobbyist, West Sussex, UK
nice one. I dont know where you got the time though!
NT
Neat! Thanks for posting it.
Ed
ehsjr wrote in news:y9ume.4571$Lb.3496@trndny05:
Terry, Where did you get the end caps for the bungy cord?
I've got a simple reversing switch diagram at the bottom of the below link. The other two links show some simple setups using servos to operate the blind tilt mechanism on a cheap blind, and a servo controlling a home thermostat. The servos are controlled using a servo control chip operated via a web page or a scheduler application on a computer.
Made them! I'm a hoarder, and amongst a thousand other things saved the disposable razors I once used, before switching to Gillette Sensor Excel. Sawn into various lengths they come in useful for various things:
- PCB/stripboard spacers
- Drill bit 'shorteners' (to prevent drilling too far)
- Misc connectors etc
In this case, I drilled holes at one end to take the curtain cord, and then secured the bungee cord at the other end with combination of self-tappping screw and epoxy (Araldite).
But as I mentioned, I'm not sure the bungee provides a net gain. OK, it takes up the slack so that the knots are a bit easier to get right. But the springiness seems to reduce accuracy. I've removed one section; may remove the other. Will report back if I see any change.
-- Terry Pinnell Hobbyist, West Sussex, UK
Terry Pinnell wrote in news: snipped-for-privacy@4ax.com:
Thank!
I love it when you can find an alternate use for otherwise throw away trash. I figured out one time that I could get perfect flanged couplings, for attaching 1-1/4" ShopVac hose to things, from spray-paint can lids. Cut off the outer cylinder, and cut a hole in the bottom of the inner cylinder. Punch several holes around the flange (formerly the top of the lid). I've used these where I needed to attach a small dust collection hose to some jig or fixture. I wish I could find something like that for the 2-1/2" size hoses.
Yes, that's a good example of the sort of improvisation I like. It's always satisfying to find bits from different surplus items that serendipitously fit together. In similar vein, it's good to find novel uses for familiar materials. Electronics cases are, well, a case in point. Tobacco tins and plastic guttering used to be some favourites of mine a couple of decades ago, as seen here:
-- Terry Pinnell Hobbyist, West Sussex, UK
Take the bungee out of the cord, and mount the motor/capstan on a plate that's on rails, or even hinged, and spring-load the plate. :-)
Cheers! Rich
I was thinking of spring-mounting the entire bedroom .
-- Terry Pinnell Hobbyist, West Sussex, UK
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Sell: China Shenzhen ZHAOWEI Machinery & Electronics Co. Ltd engages in designing , manufacturing and marketing all kinds of electric motors. They are mainly suitable for the following applications: smart home application used in sm art kitchen and laundry, medical instrument for personal care, smart E-tran smission applied in automobile, industry automation applied in telecommunic ation and a great variety of plastic/metal planetary gearbox in different s izes. In order to develop the oversea market, we are current seeking new partne rs around the world to create a bright future together. ZhaoWei is a right choice and excellent partnership with sincere services.
Company: Shenzhen ZHAOWEI Machinery & Electronics Co., Ltd URL:
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Sell: China Shenzhen ZHAOWEI Machinery & Electronics Co. Ltd engages in designing , manufacturing and marketing all kinds of electric motors. They are mainly suitable for the following applications: smart home application used in sm art kitchen and laundry, medical instrument for personal care, smart E-tran smission applied in automobile, industry automation applied in telecommunic ation and a great variety of plastic/metal planetary gearbox in different s izes. In order to develop the oversea market, we are current seeking new partne rs around the world to create a bright future together. ZhaoWei is a right choice and excellent partnership with sincere services.
Company: Shenzhen ZHAOWEI Machinery & Electronics Co., Ltd URL:
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