# Can I replace a rocker switch with...



## joker (Sep 25, 2007)

I'm hoping someone on here more electronic savy (which wouldn't take much) might have some suggestions for something I want to do.

I'm working on a prop that's run off of a shiatsu massager and I want to periodically, randomly, sequentially or any other way of switching the direction of the motors. It's currently already capable of changing directions and is controlled by a rocker switch. What I'd like to do is replace that switch with something that could change it for me without having to push the switch.

I'm not scared of 110v, but am very respectful. My soldering skills are decent, but I can definitely use crimp connectors, wire nut connectors, shrink fit tubing, electrical tape, etc...

This will be for my Psycho (shiatsu) Sam prop.

I believe the terminology for the switch is a Single Pole Double Throw with center off of SPDT center off.

Any ideas/suggestions?


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## Otaku (Dec 3, 2004)

The center-off feature is the key here. This allows the power to the motor to actually be cut before reversing the polarity. Doing a reversal on the fly will damage the motor. There's been a fair amount of discussion on the web about the best way to reverse the polarity of a DC motor without harming it, let me see if I can find some info for you.


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## joker (Sep 25, 2007)

Otaku said:


> The center-off feature is the key here. This allows the power to the motor to actually be cut before reversing the polarity. Doing a reversal on the fly will damage the motor. There's been a fair amount of discussion on the web about the best way to reverse the polarity of a DC motor without harming it, let me see if I can find some info for you.


I'd appreciate it.

Is cutting the power sufficient or should there be a pause so the motor actually slows or stops before reversing?


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## hedg12 (Jul 6, 2008)

I'd imagine you'd want to let the motor stop completely before you reverse the polarity. As far as actually reversing the polarity, you could use a couple of spdt relays. I used to use this setup to actuate add on power door locks - it should work here,too. This shows automotive relays - 85 & 86 are the coil, 87a is normally closed, 87 is normally open, and 30 is common.









Higher res here.

Not sure how you'd go about triggering the relays (555 circuit, prop-1, etc.) but you could insert a delay between releasing one relay and triggering the other. As long as the delay was long enough for the motor to stop, you should be fine.


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## joker (Sep 25, 2007)

If I'm going to use a setup that requires an external controller I'd just use a picoboo F104 or F105 and use it to turn on the power, stop and then reverse the motor.

Was hoping to find a cheaper solution though.


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## hedg12 (Jul 6, 2008)

The relays are less than $2 apiece, and a 555 timer circuit could be built for just a few dollars. Wouldn't give you a random reversal, though (at least I don't think it could, Otaku?) I'd imagine a picaxe would do the job for not too much money, too. I've never used one, but there are a few here that are pretty good with them. (hpropman for one - he's awesome with them.)


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## spinman1949 (Jun 29, 2009)

*Low budget*

Cheap gear motor.Two disks with various highs and lows like a cam and two micro switches. Not totally random, but with a really slow motor, you could have quite a few different durations for both polarities. You wanted cheap.


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## joker (Sep 25, 2007)

Doesn't have to be random. Just wanted it to change directions from time to time so that it doesn't just look lie a prop built on a shiatsu going round and round...lol.



hedg12 said:


> The relays are less than $2 apiece, and a 555 timer circuit could be built for just a few dollars. Wouldn't give you a random reversal, though (at least I don't think it could, Otaku?) I'd imagine a picaxe would do the job for not too much money, too. I've never used one, but there are a few here that are pretty good with them. (hpropman for one - he's awesome with them.)


Hoping someone can chime in with some specifics. I know what a 555 timer is, but not really how to build one or what things to consider when setting something like that up.



spinman1949 said:


> Cheap gear motor.Two disks with various highs and lows like a cam and two micro switches. Not totally random, but with a really slow motor, you could have quite a few different durations for both polarities. You wanted cheap.


 So the disks/cam would make contact depending on the ridges/valleys to turn the motor on going in one direction or the other?


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## fritz42_male (May 5, 2009)

All together now....

Picaxe!


A picaxe chip based solution wouldn't cost much more than a 555 timer and could give you randomness


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## joker (Sep 25, 2007)

fritz42_male said:


> All together now....
> 
> Picaxe!
> 
> A picaxe chip based solution wouldn't cost much more than a 555 timer and could give you randomness


OK so how do I do that?

Here's my idea of a picaxe


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## spinman1949 (Jun 29, 2009)

*Cheap solution #2*

Yes either direction.

One switch would be activated by one disk/cam, and the other would be wired to reverse the polarity and would be activated by the other disk/cam. Valley's on both disks would be to stop the motor, and of course no peaks must ever occur at the same point for both disks/cam. That would be very bad !!!

I am no electronic wizz so I do stuff old school. Sounds like the picaxe is the easy and inexpensive solution as far as electronic is concerned. I will go to school along with you in this area. Hopefully we will see a circuit diagram. I imagine it will be a simple breadboard project I hope.


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## joker (Sep 25, 2007)

spinman1949 said:


> .... I am no electronic wizz so I do stuff old school. Sounds like the picaxe is the easy and inexpensive solution as far as electronic is concerned. I will go to school along with you in this area. Hopefully we will see a circuit diagram. I imagine it will be a simple breadboard project I hope.


Yeah fritz42_male has mentioned the picaxe solution a couple times recently so I'm hoping he'll chime in with a diagram, how-to, parts list or direction to start.

I haven't researched it a whole lot, but every thing I've seen so far has use batteries so I'm not sure how it will interact with 110v. Relays maybe?


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## spinman1949 (Jun 29, 2009)

*110 volt ?*

Now you have me questioning this project. Can you confirm if the voltage is AC or DC. Maybe the massager has an AC input, but somewhere it likely ends up DC if the switch just reverses polarity. To reverse direction on an AC motor is way more involved. The electro wizz kids can confirm this.


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## joker (Sep 25, 2007)

spinman1949 said:


> Now you have me questioning this project. Can you confirm if the voltage is AC or DC. Maybe the massager has an AC input, but somewhere it likely ends up DC if the switch just reverses polarity. To reverse direction on an AC motor is way more involved. The electro wizz kids can confirm this.


If you can tell me how I'll see what I can do. If it require a multi-meter I need to buy one of them anyway.


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## fritz42_male (May 5, 2009)

joker said:


> Yeah fritz42_male has mentioned the picaxe solution a couple times recently so I'm hoping he'll chime in with a diagram, how-to, parts list or direction to start.
> 
> I haven't researched it a whole lot, but every thing I've seen so far has use batteries so I'm not sure how it will interact with 110v. Relays maybe?


I'm just finishing a howto on the basic board. I've yet to try it with some solid state relays - I have the relays but not a lot of free time at the moment.

The current board works fine for driving servos and for triggered and variable inputs such as a pot.

Should get the basic howto up this weekend and with luck will have tried the solid state relay timer setup.


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## spinman1949 (Jun 29, 2009)

*Multimeter*



joker said:


> If you can tell me how I'll see what I can do. If it require a multi-meter I need to buy one of them anyway.


Yes quick answer is multimeter. I have a hometics massage cushion for a chair. It has an AC to DC converter. 110 AC to 12 volts 2 amp output. The very design and intent of these devices leads me to believe the actual motor or motors are DC.

If you are going to build electrical props, a multimeter is almost a given, so nows the time.


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## hedg12 (Jul 6, 2008)

spinman1949 said:


> Now you have me questioning this project. Can you confirm if the voltage is AC or DC. Maybe the massager has an AC input, but somewhere it likely ends up DC if the switch just reverses polarity. To reverse direction on an AC motor is way more involved. The electro wizz kids can confirm this.


Good point. Does it use a wall wart?


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## joker (Sep 25, 2007)

hedg12 said:


> Good point. Does it use a wall wart?


No it doesn't use a Wallwart. It has a hard wired cord just like a lamp, radio, etc...


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## hedg12 (Jul 6, 2008)

That doesn't rule out DC, but would have made it easier to confirm.


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## spinman1949 (Jun 29, 2009)

*Some disassembly*

Well you want to be a prop builder, so part of prop building is taking stuff apart and seeing how it works. So lets take that sucker apart and find out if it is DC or not. DC motors of this size are usually armature and brush based. The case will be magnetic. Common wiring in DC circuits is red wire + black wire -. You should be able to follow the AC input to a board. Find the wires that go to your toggle switch. If this is indeed DC more proof will lie here. If wiring is color coded as I described, the wiring will be reversed from one side of switch to the other. Of course a multimeter will provide an easy solution, but you may be able prove if AC or DC visually. If you can remove the motor and want to play, you could stick the motor shaft in a drill, connect flashlight bulb or even an led to the input wires and instant generator. You may need to reverse the drill and turn the motor slow at first if you use an led.

Of course you may get real lucky and find a label on the motor that will provide the EZ answer. LOL !!!


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## fritz42_male (May 5, 2009)

I just opened my Shiatsu massager up but can only identify a few obvious components. There is a BTB04 Sensitive Gate Triac, a few caps, resistors and a diode. Without dismantling it further I can't start a diagram and I'm short on time. There are a few components which could be 1/2 or 1/4 W resistors or they could be large diodes - they aren't marked as far as I can see.

If I get a chance over the weekend I'll get the meter out.


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## spinman1949 (Jun 29, 2009)

*Dc*

Looks like Fritz answered the question. DC it is. Now for that Picaxe circuit ?

HMMMMM !!!! :googly:


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## hpropman (Jul 27, 2008)

fritz42_male said:


> I just opened my Shiatsu massager up but can only identify a few obvious components. There is a BTB04 Sensitive Gate Triac, a few caps, resistors and a diode. Without dismantling it further I can't start a diagram and I'm short on time. There are a few components which could be 1/2 or 1/4 W resistors or they could be large diodes - they aren't marked as far as I can see.
> 
> If I get a chance over the weekend I'll get the meter out.


Sorry that I am late to the party been busy lately. OK need to see a picture of the inside of the massager to make sure that it is a DC motor or not. It sound like it is but I want to make sure before I give any direction. AC is not something to mess around with. If the motor is AC then it can be switched by a pair of DPDT (double pole double throw) relays relays with a pause to allow the motor to stop. And a DC motor can be controlled with relays also or transistors or fet's. I know that you are anxious Joker but because we may be dealing with AC I don't want to rush into anything and see you get hurt. The picaxe can easily handle this we just have to see what we are dealing with first. I would purchase the multimeter as soon as possible it will become like your right arm. Here is great site to learn how to use it.

http://www.ladyada.net/learn/multimeter/index.html


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## joker (Sep 25, 2007)

hpropman said:


> Sorry that I am late to the party been busy lately. OK need to see a picture of the inside of the massager to make sure that it is a DC motor or not. It sound like it is but I want to make sure before I give any direction. AC is not something to mess around with. If the motor is AC then it can be switched by a pair of DPDT (double pole double throw) relays relays with a pause to allow the motor to stop. And a DC motor can be controlled with relays also or transistors or fet's. I know that you are anxious Joker but because we may be dealing with AC I don't want to rush into anything and see you get hurt. The picaxe can easily handle this we just have to see what we are dealing with first. I would purchase the multimeter as soon as possible it will become like your right arm. Here is great site to learn how to use it.
> 
> http://www.ladyada.net/learn/multimeter/index.html


Oh trust me I'm in no hurry to do something stupid...lol. The prop will be just fine as is, but if we could make it alternate directions too that would make it that much better and break of the repetition. I'll try to get a pic of the internals this weekend.


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## Decrepit Desecr8shun (Aug 10, 2009)

Well having been into R/C cars,boats and planes...I would take issue w/ the idea of DC motors not being reversible w/o damage. As reversing these motors happens quite often(except in R/C airplanes of course) w/any noticeable damage which in many rebuilds,due 2 parts simply wearing out or me overpowering them in the quest for more speed. Now,back 2 the main gist of my post,as far as a true random circuit...not feasible w/o a large amount of computing power @ your disposal and a very complicated circuit design. In point of fact,chaos mathematics proves that as random as something can be there will still be a pattern 2 it. Now that I've sapped all your brain power,check out:

http://www.patentstorm.us/patents/6889349/claims.html and then add an appropriate 2 your mechanism(voltage & amperage) output relay and you will be good 2 go. If you need any further help,let me know.

1 further thing,I seriously doubt the motors are a/c as you stated that they are reversible. Massagers do not cost enough 2 cover the expense(and it is considerable) of a reversing A/C motor.


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## joker (Sep 25, 2007)

Decrepit Desecr8shun said:


> ...as a true random circuit...not feasible w/o a large amount of computing power @ your disposal and a very complicated circuit design. In point of fact,chaos mathematics proves that as random as something can be there will still be a pattern 2 it. Now that I've sapped all your brain power....


Hahaha, sounds like something I would've said...lol.

Honestly I could care less if it's random. I don't anyone will see it long enough to figure out a pattern anyway.

Thanks for the link...I'll check it out.


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## fritz42_male (May 5, 2009)

I'd be more inclined to rig a servo to press the rocker switch - quick n easy and no messing round internally with the massager (which I reckon is AC mains).

A simple servo controller (e.g. a Picaxe chip) and a bit of programming maybe tied into a PIR and you are sorted.


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