What is this board with spring as switches

[Banksy5555]

Won't let me put a picture in Hi I was hoping to bypass a button on this bord and when I took it apart the buttons wasn't as straight forward as I thought, they was spring buttons. Was just wondering how they work and if I can still bypass it so it is on constantly on, as you can tell I have no knowledge in electronics so a basic guide would be nice many thanks

 

[BradtheRad]

Won't let me put a picture in

The 'Add an Image' function is reliable and straightforward.

It accepts certain graphic formats.

Copy the entire BBC code and paste into your message.

 

[Banksy5555]

**broken link removed** was using threw my phone heres the picture

 

[betwixt]

I would guess the springs are just to extend the connections to a front panel with the compression providing a firm contact. You can probably link a wire from one to another to simulate the switch action.

Brian.

 

[Banksy5555]

well that was what I thorght but when I looked at the face plate with the buttons on they was no conectors, well its not even buttons its just plastic when I get home ill put some more pictures on

the only thing I could think of if it was heat sensitive but I don't no

thanks

 

[FvM]

Spring contacts like these are often used with a capacitive touch controller, setting up touch fields on a plastic case.

Please resend the photo it's gone now, apparently no correctly inserted as image.

 

[BradtheRad]

Attachments occasionally expire, for reasons known only to the system interface.

I kept a browser tab with the photo. Here it is, condensed.

 

[Banksy5555]

well I'm in a bit of a pickle over this and need it sorting, so managed to pluck up the courage to plug it all in and star touching the springs.
I found out that I don't actually need to touch the spring to turn it on but need to be pretty close, it also has a LED at the base of the spring is it possible that its like a laser switch I'm clueless.

I will get round to putting up some more photos on this

 

[FvM]

As said, it's a capacitive touch sensor. With respective high sensitivity, it works as a proximity switch.

If it's optical, it won't need spring contacts.

 

[Banksy5555]

thanks FvM that doesn't mean much to me but thanks, is they any way I can have it on all the time.

very new to it all

 

[BradtheRad]

FvM's reasoning gets my vote. The springs are not directly connected to circuitry. They are connected to capacitive touch pads on the enclosure. It is a safety feature protecting the circuitry. Perhaps it is in widespread use.

If there were a direct connection, then it would convey static charge from us, because we can carry several kilovolts without being aware of it.

 

[Banksy5555]

this is the enclose but it just looks like plastic

a few more pics on the board

sorry if you can not see the picture its the only way I know to put them on

 

[BradtheRad]

Your 4 photographs show up fine.

I guess I had the wrong impression... The springs are not in contact with touch pads on the face of the enclosure. Instead it may be a proximity sensor, like a buzzer circuit which you attach to a doorknob, and which responds if someone touches the doorknob from the other side of the door. No need for a complete current loop. It needs to be very sensitive.

The opto device appears to be a detector, not an led. There's a chance it is meant to detect the shadow of your hand over the buttons.

 

[d123]

The little I know, some touch devices can be made to work with anything (pencil, finger, gloved finger, etc.), some need human finger to make them work (the ones that you need to take gloves off to get them to do anything), can't remember reason right now.

Possible your device needs 2 inputs to do anything (light sensor detecting a shadow/darkness AND a button being activated), so - I have no idea how you need this to look when always on, so may not fit in with your objective - try experimenting with placing different materials on the button spring you need in order to lightly weigh it down and perhaps also necessary covering/shading the thing that looks like a photodiode. Whatever you use, if doesn't have to be warm-human-based to touch the spring/plastic interface, maybe can place something over it just needing be very close if it is a proximity type of button.

 

[betwixt]

It would be interesting to see the front of the enclosure rather than the inside of it. Doesn't it have any markings to indicate what the touch areas do?

There is an LED inside each of the springs and an IR data detector on the board as well but the alignment of them suggests they are not coupled to each other. I would guess the LEDs are visible to illuminate the touch area and the IR is for picking up from a remote control unit. Probably the board is from air conditioning or temperature control equipment.

Brian.

 

[FvM]

An application example from a NXP touch application note, operating the touch sensor through a plastic case front. The foam pad can be replaced by a spring.

 

[Banksy5555]

thanks all for your help

so any ideas on keeping it running constantly?
Iv tried holding the spring down and turning it on but it doesn't come on until I wiggle my finger a bit then it will come on.
can I just solder up from the back of the board so there connecting or will that not work,
my biggest worry is blowing something so it doesn't work
but willing to try

 

[BradtheRad]

Did you ever see the board operating properly?

Does it turn on when you fiddle with the springs?

Does power come in at the left-hand connector?

It has two led displays, each 4 digits (or 3+1/2). Is it correct that these display an updated reading for ten seconds? Then it shuts off to conserve battery power? Did you see it do this, or a different action?

A timer circuit somewhere may trigger when you fiddle with the springs. To keep it on continually, you might succeed by attaching a pull-up (or pull-down) resistor to its trigger pin, to keep it activated.

 

[d123]

If the integrated circuit has anything written on it, that might help some-one to be able to suggest something, and providing the name/model of the device, otherwise it's just guessing a lot of things. It could be as simple as Brad said.