I'm in the process of adding a under dash A/C unit into my car and I want to change the fan speed selector switch that came with the unit to a push button type switch unit by using these momentary push buttons and some relays. I want the push button switch that I'm trying to make to have 4 buttons total. 1 button for "off" and 3 other buttons for the "low, med & high" fan speeds & I would also like for each button to cancel the other one out when another one is pressed kind of like one of the A/V selector switches. I don't like the look of the switch that came with the unit & was thinking about mounting it inside the glove box out of sight but If you guys can help me out with something to use these buttons I am going to flush mount them somewhere on the dash where they are easily accessible. Thanks in advance!

 

I was looking around on the web and found this. maybe this can help with some ideas...

http://electronics.stackexchange.com/questions/77183/pushbutton-ground-selection

 

You can buy 4 sets of switch as below, but they must be assembly together as a 4 switches selector.

Two Pole Push-Button Switch.

 

To do this with fewest parts requires you to learn how to apply a micro-controller to this project. The method with the quickest learning curve is to use an Arduino or PIC-Basic

 

To do this with fewest parts requires you to learn how to apply a micro-controller to this project. The method with the quickest learning curve is to use an Arduino or PIC-Basic

I bet you give him a heavy mission, I just thought that maybe I can suggest him to using CD4017 and some relays, but maybe it will more complicated.

 

You are looking for a Radio push button circuit.

You can make one with a CD4078 NOR gate, a CD4042 4-bit latch, 8 resistors, 4 capacitors, and 4 transistors to drive the relays. If you are interested in such a circuit I can post the diagram.

 

A 16f54, some cheap mosfets and resistors, one coil for clocking.

Or use a 4 relay board instead of the mosfets

Cd 4017 isn't a bad idea just you have to cycle through all devices.

The 16f54 costs less than a dollar, 20 pins ic. It doesn't need parts beside clocking, reset and the usual buffer capacitors. I'd use a switcher for the car to prevent the setting going off.

 

You can buy 4 sets of switch as below, but they must be assembly together as a 4 switches selector.

Two Pole Push-Button Switch.

Doesn't look heavy enough for automotive - some old washing machines had ganged latching push button selectors that would be more like it.

 

Doesn't look heavy enough for automotive - some old washing machines had ganged latching push button selectors that would be more like it.

Yes, I'm afraid of the current maybe not enough, I saw the fan have the switches could be used, but I can't remember the name, they look similar as used in washing machine.

There is one kind of push switches for fan - fan keyboard push button switch.

 

Yes, I'm afraid of the current maybe not enough, I saw the fan have the switches could be used, but I can't remember the name, they look similar as used in washing machine.

There is one kind of push switches for fan - fan keyboard push button switch.

Another possibility is a cheap halogen heater. They have various switchgear depending on make/model but I have seen one with a ganged latching push button bar.

 

Yes, I'm afraid of the current maybe not enough, I saw the fan have the switches could be used, but I can't remember the name, they look similar as used in washing machine.

There is one kind of push switches for fan - fan keyboard push button switch.

I'm still having problems with More options/email notifications.

Its always greyed out and no matter how many times I tick the check box for watch thread, its cleared next time I post/edit.

 

I'm still having problems with More options/email notifications.

Its always greyed out and no matter how many times I tick the check box for watch thread, its cleared next time I post/edit.

I already asked Rob via PM, you just waiting for his reply, maybe you can describe some more details if needed.

 

I already asked Rob via PM, you just waiting for his reply, maybe you can describe some more details if needed.

Thanks - the 2 check boxes can now be independently ticked, which looks like it should be working now.

Too early to say whether any notifications will be forthcoming.

 

Here's a circuit I generated to perform the Radio Push Button function using only two ICs, which should do what you want.

 

Can the 4514 be replaced with something smaller like 4028, 4555 or 4556?

Allen

 

Can the 4514 be replaced with something smaller like 4028, 4555 or 4556?

No. Those don't have a latch function, which is needed for this design.
But if you can find a smaller binary or BCD coded latch, that should work.

 

The only smaller decoder with latch I can find is the 74HC137, but then the Vcc has to be dropped to 5V which is not so good for automotive application.

Allen

 

The only smaller decoder with latch I can find is the 74HC137, but then the Vcc has to be dropped to 5V which is not so good for automotive application.

It just means you would have to add a 5V regulator to the circuit, such as a 7805.
But then you start to lose the area savings that the 74HC137 gives.

Edit: Also the latch signal has inverted polarity on the 74HC137 so, in addition, you would have to add an inverter to the circuit.