Power circuit required

[Foxmeister]

Hi all,

im lookin for some info, im an electrician by trade but dont do much with electronics so still an amateur really.

What im doing is building a sat nav(Sony aftermarket) into the car dash, completely flush and want it integrated to work with the car ie power etc. Problem is the power button is on the side of the unit and obviously needs pressed everytime to power on and power off the unit manually.

Ideally, i'd like to be able to wire this up to work with a switch live in the dash so it comes on with ignition everytime and off again when key removed, what would be required to do this??? Heard of a "555" circuit but have no knowledge of this, would this be a solution? Or is there any other ways?

Failing that i will just extend cables from the button and add a new button onto centre console somewhere

Cheers, Mick

 

[DerStrom8]

Welcome to ETO, Foxmeister!
A 555 timer is a chip and really has nothing to do with what you are trying to do.
Are you willing to "hack" the sat nav (By that, I mean open it up and move around some parts, like the old switch)?
This would make it much easier, but it is also important to know how to solder. What kind of experience do you have with soldering, etc.?
Der Strom

 

[Foxmeister]

Welcome to ETO, Foxmeister!
A 555 timer is a chip and really has nothing to do with what you are trying to do.
Are you willing to "hack" the sat nav (By that, I mean open it up and move around some parts, like the old switch)?
This would make it much easier, but it is also important to know how to solder. What kind of experience do you have with soldering, etc.?
Der Strom

Thanks for reply Derstrom8

I have soldered previously and done it sometimes in my profession so would grade my self as adequate. Just ordered my own new soldering iron aswell.

I intend to open the sat nav anyway, bought a 2nd hand one to play with and see how it turns out first so no loss and no fear! Ha.

Can you instruct me on what would be required to get the unit to function as described above then?

Thanks for help

 

[DerStrom8]

One more important piece of information that we will need--What type of switch is the power switch? Is it a slide-switch, push-button, etc.? Also, if it is a push-button, what type is it? Momentary tactile, or is it the kind that you push in and it stays in, and push again and it pops back?
Der Strom

 

[Foxmeister]

Sorry, never went into detail.

Its a push button switch, standard make and break, not hold on.(push once, on, push again, off)

 

[DerStrom8]

Sorry, never went into detail.

Its a push button switch, standard make and break, not hold on.(push once, on, push again, off)

Okay, then. I would recommend simply bypassing the power switch on the side (solder a jumper wire across the terminals) and routing the power wires through, for example, the radio circuit (power to the radio turns on when you turn the ignition switch). By bypassing the power switch, it will be on any time there is power to the navigation system, and it will shut off when you cut the power (turn off the car). I think this would be one of the easiest ways to do what you want to do.
Der Strom

 

[Foxmeister]

Okay, then. I would recommend simply bypassing the power switch on the side (solder a jumper wire across the terminals) and routing the power wires through, for example, the radio circuit (power to the radio turns on when you turn the ignition switch). By bypassing the power switch, it will be on any time there is power to the navigation system, and it will shut off when you cut the power (turn off the car). I think this would be one of the easiest ways to do what you want to do.
Der Strom

This is what i had in mind originally, so basically connect the switch permanently and when its plugged in via 12v supply it should power up, would it have to have auto power up as standard to work this way as i dont think the unit does? i.e if i currently plug in the charger to the cigarette socket a light comes on to tell me its charging, but i still have to manually press the power button to operate the unit, same when i turn key off, unit stays on till button is pressed.

 

[crutschow]

This is what i had in mind originally, so basically connect the switch permanently and when its plugged in via 12v supply it should power up, would it have to have auto power up as standard to work this way as i dont think the unit does? i.e if i currently plug in the charger to the cigarette socket a light comes on to tell me its charging, but i still have to manually press the power button to operate the unit, same when i turn key off, unit stays on till button is pressed.

Then it sounds like the switch is a momentary switch and the on/off function is provided by the electronics. In that case just add two wires to the switch terminal and bring them to a momentary switch on the dash.

Since it has a battery then you may have to add a circuit to pulse the switch to turn it off when you remove the power.

 

[Foxmeister]

Then it sounds like the switch is a momentary switch and the on/off function is provided by the electronics. In that case just add two wires to the switch terminal and bring them to a momentary switch on the dash.

Since it has a battery then you may have to add a circuit to pulse the switch to turn it off when you remove the power.

So it cant be automatically switched on/off with the 12v ign live???

Extending the switch onto the dash is one option but would prefer the unit to power on and off with the ign if its poss?

 

[DerStrom8]

So it cant be automatically switched on/off with the 12v ign live???

Extending the switch onto the dash is one option but would prefer the unit to power on and off with the ign if its poss?

I wonder if you could just use the part of the ignition switch that the starter is connected to in place of the momentary switch on the device? In other words, use the ignition switch for more than the regular purpose? If you do this, I would assume you would need to somehow isolate it from the ignition circuit somehow.
Der Strom

 

[crutschow]

I think you need an isolated contact to turn the unit on and off. A small 12V relay with with one of the NO contacts across the pushbutton should work. You would need the relay to pulse when the power comes on and also when the power goes off. If the relay coil is non-polarized. a large capacitor in series with the coil may work.

You would still need to add a manual emergency switch across the contacts to change the sequence, in case the GPS on/off gets out of sequence.

 

[Foxmeister]

Okay, not too bothered on turning this into a self switching circuit as much, rather know what im looking at.

Heres a quick pic of somebody else connecting some wires onto a switch
**broken link removed**

I have a similar looking white small switch on my sat nav, but its all plastic and not sure what this guy has done here, can anybody clarify what im looking at and where and how to solder onto the switch to extend cables from it?

 

[Foxmeister]

Anybody???

Needing help with this small white switch, how do i solder to it???

 

[DerStrom8]

It is difficult to say without actually seeing YOUR board. Could you possibly post a picture of the inside of your sat nav device? This would be extremely helpful.
Der Strom