Windshield wiper

[Keanu69]

Hello guys,
I have a car wiper control system to be made, which will be controlled by + and -, the speed (there should be 10 speeds) should be displayed on the screen. There is not a rain sensor in the system. Would anyone be able to help with the digital schematic? A microcontroller cannot be used in the schematic.

 

[Reloadron]

When you mention 10 speeds are you referring to actual wiper motor speed or for example 10 wiper delay settings?

What exactly did you have in mind for a display? Displayed on screen isn't saying much. May I assume this is a school assignment since you mention no use of a uC? A Google of 555 wiper delay circuit will give you plenty of examples using a 555 timer IC. If you want actual speed control you could also likely use a 555 timer with a PWM out driving a MOSFET and a rotary switch with 10 positions for resistors controlling the PWM rate.

You really need to better define the project in detail. Anyway barring a uC I would look at circuits developed around the 555 timer chip.

Ron

 

[crutschow]

Wiper motors typically don't operate well at a low speed, thus they do an intermittent control to delay between single wipes.
Would that work for you?

 

[alec_t]

Welcome to ETO!
Is this a school/college assignment?

 

[MaxHeadRoom78]

Hello guys,
I have a car wiper control system to be made, which will be controlled by + and -, .

If this is meant to indicate a motor reversal, that is not the norm for wiper mechanisms which are generally uni-directional worm and pinion, with the reverse achieved mechanically.

 

[gary350]

60 years ago some cars had a knob connected to variable resistor, turn knob right wipers go faster. Now you can do same thing with a mosfet.

 

[Externet]

It is not done controlling speed; it is done controlling interval period.

 

[shortbus=]

60 years ago some cars had a knob connected to variable resistor,

And some still had vaccum wipers. But never saw a car having an adjustable speed control like that just a high and low speed. What make and model used the pot like your talking about?

 

[Reloadron]

And some still had vaccum wipers. But never saw a car having an adjustable speed control like that just a high and low speed. What make and model used the pot like your talking about?

Thank you for reminding me of something I remember so well. My first cars had vacuum wipers.

Looking back on this I could not remember the inventor of what was called intermittent windshield wipers. The credit actually goes to Robert Kearns. I do recall the inventor having to go to court with the then big three auto manufacturers. There was a movie about it:

Robert Kearns invented the intermittent windshield wiper and spent 12 years suing the big Detroit automakers for stealing his idea. "Flash of Genius" is a true story based on a New Yorker magazine article.

There were circuits out later using a 555 timer chip where a simple pot was used to vary the delay between pulses which triggered each pass of the wipers. Each cycle of the wipers was initiated by a single short pulse. Somewhere in all my junk I have a little wire wrap circuit board I built using a 555 and tiny relay. The pot really did not change the speed but how often the wiper motor would cycle, thus the term intermittent was used. I put that little circuit together maybe 35 years ago. My truck and my wife's little old 99 GMC Tahoe have two wiper "speeds" fast and slow, beyond that there are intermittent settings.

Ron

 

[Nigel Goodwin]

And some still had vaccum wipers. But never saw a car having an adjustable speed control like that just a high and low speed. What make and model used the pot like your talking about?

Never seen one, but I imagine there probably was?, however Citroen were using variable speed control a VERY long time ago, possibly using PWM?.

 

[MaxHeadRoom78]

One of my first auto's in the UK was the Ford Popular, claimed to be the cheapest auto made to that date.
Featured vacuum wipers, they went like the devil when going down hill ( high Vacuum!) and almost stopped going up hill.
Other features, 6vdc system, gravity fed radiator, bare bones trim, inside and out.

 

[shortbus=]

One of my first auto's in the UK was the Ford Popular, claimed to be the cheapest auto made to that date.
Featured vacuum wipers, they went like the devil when going down hill ( high Vacuum!) and almost stopped going up hill.
Other features, 6vdc system, gravity fed radiator, bare bones trim, inside and out.

Back in the 1970s I had a Ford Squire, which I think was an offshoot of the Popular. It had the same problem with the vacuum wipers. It was a fun little car though.

 

[shortbus=]

Citroen were using variable speed control a VERY long time ago, possibly using PWM?.

Found this, seems like the driver didn't control it though.
"Earlier attempts at automatic wipers, like on the 1970 Citroën SM, weren't so sophisticated. The Citroën system adjusted the intermittent wiper delay based on the electrical current draw of the wiper motor. A wiper blade glides more smoothly over a wet windshield, using less energy, and a control circuit in the SM used that to indirectly determine if rain was present" from - https://www.popularmechanics.com/cars/a10323/how-it-works-automatic-windshield-wipers-16663151/

 

[camerart]

Hi,
I remember my dad's Ford popular had vacuum wipers, and going up hill when it was raining, where the wipers almost stopped.
Camerart