Good for Windscreen wiper intermittent?

I can't convince that page to load (probably a temporary problem with their server), however one thing to consider will be the system used to bring the wiper back to its parked position.

Ideally you would want to use the wiper parking arrangement already in the wiper motor, described here (though I've seen wiper motors with fewer pins):

When the intermittent mode is turned on, you will want the wiper motor "Low Speed" terminal to be connected to one of the "Parking Switch" terminals, with the other "Parking Switch" terminal going to positive. Your timer device should be connected to provide a short pulse to "Low Speed" (enough to move it so that the Parking Switch becomes closed again), then wait the desired period before the next wipe cycle is required (plus the time to be taken by the wiper in completing the current stroke) before pulsing again.

I've got no idea whether the device linked to can do that because I can't see it.

Of course the problem with getting the device to return the wiper to the park position by timing the period during which the motor is powered (and not needing to connect up the Parking Switch) is that if the wiper is not in the park position when it starts up (such as when shifting from constant wipe to intermittent while the wiper is in mid-stroke), it will finish each cycle with the wiper located on the windscreen wherever it was when intermittent was enabled, which might be right where you want to be looking

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On Stardate Sun, 18 Sep 2016 04:52:17 +0000 (UTC), snipped-for-privacy@telling.you.invalid (Computer Nerd Kev) applied digits to the keyboard and routed the information from some kind of brain (presumably), thusly:

i did this a long long time ago with an old car.

as i remember it i needed to use the relay contact to break the exiting wire and on changeover apply power briefly to the motor.

then quickly release the relay and reclose the original wiring to allow the homing and stopping circuit to function.

if you just apply power to the original wiper wire it blew a fuse when the wiper hit home.

Hmmm, intersting thanks Reese. Hopefully mine's a bit simpler and I can just use that module. My car isn't *that* old (a 1985 Honda City), most cars it's age had intermittent. It's just that it's the 'E' model (for economy) and they're really no frills - which is part of the reason I like it, it's easy to maintain.

-- Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy little classification in the DSM*." David Melville (in r.a.s.f1) (*Diagnostic and Statistical Manual of Mental Disorders)

Thanks Kev. Hopefully it'll load for you soon and you can see if you think it'll do the job (I don't mind if I have to do two strokes per intermittent if I can't set the delay short enough for one).

As it's quite cheap I've ordered it anyway and am hoping ... I was wondering if anyone could give me an opinion while I wait the weeks to get it delivered. ;)

(Also I hope that my back's up to the task of fitting it. Last time I needed to do something under the dash I gave up. However, as usual my mind keeps on writing cheques that my back can't cash. :-/ )

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*." 
David Melville (in r.a.s.f1) 
(*Diagnostic and Statistical Manual of Mental Disorders)

They always used to have a curved track and wiper contact that kept the motor powered anywhere other than the resting position - no matter where it was when you switched it off, it always found its way home.

It turns out Aliexpress have broken compatibility with the weird browser I run on the PC I use for posting to Usenet. On another computer I've now seen the listing.

It should work. Looking closely at one of the pictures, I was also to figure out that the chip they're using is a 4541B. They comment that by using this they have far better timing performance than with a standard 555, but if they're using that 100uF Electrolytic capacitor for the timing circuit, changes in its characteristics over time and temperature variations will swamp any advantage in stability offered by the 4541. Anyway that doesn't matter for a windscreen wiper application, I'm just wondering why they didn't use a 7555 as I can't see how they're using any of the 4541's special features.

I'm surprised how good my Chinglish has become (which is funny because when I'm in the city, I can't understand a thing they say in person). When power is applied the relay turns on for a time set by one of the trimpots, after that it turns off and waits for a time set by the other trimpot to turn on again and restart. They don't say which trimpot sets which time delay, or what the mysterious jumper next to the relay (marked S1) does.

Indeed you might have to put up with two wiper strokes if you can't get the first time setting close enough to the minimum.

Oh look, I can see you in the transaction history. An A3 member, I think you're above me! :)

I fear for my own back when doing things under the car dash and there isn't even anything wrong with it. :)

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Thanks for checking that out fo rme Kev. When I fit it I'l leave it so that it's accessable at least for the first few uses.

Heh! I've been rebuilding a couple power amps so bought some hardware for that job as well as a couple kits, a breadboard and some packs of resistors, capacitors, diodes etc. I've decided to try to learn more by 'doing'.

Heh, I remeber that feeling from pre-injury. Everything's built-in and not meant to be worked on.

Cheers,

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*." 
David Melville (in r.a.s.f1) 
(*Diagnostic and Statistical Manual of Mental Disorders)

Yep, however there seems to be a bit of overlap cos if you switch it off just as it starts its stroke then it often stops a couple inches above the rest position.

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*." 
David Melville (in r.a.s.f1) 
(*Diagnostic and Statistical Manual of Mental Disorders)

As noted in the link I posted, the park switch is open circuit for for about 10% of the cycle. So it will stop close to the beginning of that park position range, and if you don't apply power for long enough to get out of it, the park switch won't provide power for the motor to go around and return to the start again.

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Thanks. Yeah I had a quick look at that link then decided it wasn't going to help me much as I'm hoping to wire the controller into the switch end of the wires. I'm aware of the parking arrangement as for the last few years I haven't had intermittent (as well as the years before it became commonplace) and so have a habit of flicking the switch on, then off again manually as soon as the wipers have moved through about 15 dgerees of their ~90 degree travel.

Cheers,

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*." 
David Melville (in r.a.s.f1) 
(*Diagnostic and Statistical Manual of Mental Disorders)

Put the switch of this device in parallel with the existing wiper parking switch. and set the on time long enough to get the wiper going and the off time to whatever, eg: 15 seconds.

If your wipers don't self-park you'll have to arrange that first.

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This email has not been checked by half-arsed antivirus software

Thanks, yeah that's a thought, leave the existing switch as-is and just use this to feed power to the 'low speed out' side of the switch, using it's own switch. (I can't get near the wiper motor proper, at least without major surgery. Best I can tell it's fitted into the 'well' below the windscreen before the top part is welded on.) I have been considering splicing this into the first stage of the switch then changing the second stage to normal speed continuous and doing away with the 'fast' speed. However if I do that I might need a diode on the output so it's not back-fed during continuous use - if that's likely to bother it - probably not as it'll be going into an open relay.

Actually the use of a diode (or two) might be handy if I can't get the interval short enough to do a one wipe cycle. The voltage drop might slow the motor enough ... (Thinking out loud.)

They do that or I wouldn't even be considering this project.

Cheers,

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*." 
David Melville (in r.a.s.f1) 
(*Diagnostic and Statistical Manual of Mental Disorders)

It is highly unlikely that is in a welded in space, it would be able to be removed,even if difficult, without cutting any body.

I have been considering splicing this

That's a shame, on some vehicles they're about the easiest part to get to.

Exactly. An open relay won't be bothered by it at all. Just make sure you wire the power connection on the relay to a constantly active positive supply, not the power from the low speed motor line. otherwise you might power the intermittent circuit even when in continuous wipe mode (not that this will cause any problem except unnecessary wear on the relay). Actually this will only be a problem if the relay wired in the "normally closed" position, I don't have time to check whether you'll need to wire it up like that or not to get it to begin stroke as soon as the intermittent mode is turned on.

Not likely. A bunch of diodes in series might make enough of a difference to the motor speed, but this will reduce the torque of the motor as well, and generally be a rather poor way of solving the problem.

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I know - not in this car though.

I'll spend more time thinking on it when it arrives and I've had time to play. Thanks for the advice, always appreciated.

Yeah, was a tangential thought while typing. Must learn to leave those out ... ;-)

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*." 
David Melville (in r.a.s.f1) 
(*Diagnostic and Statistical Manual of Mental Disorders)

Yeah you're right. I just went out and checked. The linkgages and spindles the wipers fix to are all inaccessable in the 'gully' but the motor is mounted underneath with the drive spindle to the linkages going through the firewall.

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*." 
David Melville (in r.a.s.f1) 
(*Diagnostic and Statistical Manual of Mental Disorders)

Once upon a time on usenet Computer Nerd Kev wrote: [snipped]

LOL! Speaking of Chinglish I found this today. It's from a description of an audio amplifier on AliExpress;

"The 2.1 version of the amplifier design a single power supply, this is the power of design, the main feature is cheap, practical, elegant design is taking, light show design line, the machine can not find a jumper, clean look hot moaning large pond filter NE5532 low frequency handling sealed potentiometer Kingboard sided FR-4 1.6mm sheet from the perspective of each element are perfect acoustics and aesthetics to consider whether or not the intentions of the senior players at a glance!"

I didn't make that up, honestly! A friend wanted a small amp for driving PC speakers so I was browsing the site;

's the worst I've seen so far this year.--Shaun."Humans will have advanced a long, long way when religious belief has a cozylittle classification in the DSM*."David Melville (in r.a.s.f1)(*Diagnostic and Statistical Manual of Mental Disorders)

I've seen "flequency" on the specification plate of a Japanese product........................

Wow! My Chinglish certainly hasn't advanced anywhere near the level required to decode that. I'm not sure if it's safe to think about a "clean look hot moaning large pond filter". :)

Mind you, if you look up the forign Aliexpress sites I think the listings are shown in their native language, so perhaps it's actually an automatic translation by Aliexpress. Then again they often reply to questions in the sort of tortured English that I can't even imagine a computer being able to invent, so I don't know. Maybe the sellers type in their attempt at English and AliExpress translates that into the other languages, in which case I can't imagine what those poor forigners have to put up with.

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