What type of switch (button) would be ideal for a low profile button? - Page 1
Forum section: electronics / beginners

author: Decoman
author_rank: Regular Contributor
timestamp: November 28, 2017, 09:05:13 pm
content: Note: The notion of "low profile" would be about the visible part above a surface where a button would be install onto, but also the depth of the button beneath the surface, inside the construction where the button was installed.So I will be building and rigging a 1:350 Star Trek Enterprise refit model, and thinking about having buttons on a slim stand beneath the model, I am interested in learning what types of buttons might be ideal for such a project.The nice part is that, I can probably afford more expensive stuff, if that is what it takes to use special buttons.If I could have a preference, I would prefer some kind of touch sensitive surface, more or less flush with the surface the button is mounted on, or perhaps the heat from the finger would allow the button itself to be placed under the top surface of the thing.What wouldn't work, is some kind of tall button, and so far, I've seen switches/buttons that are about 2cm tall, which I find a little too tall.The design and the exact measurement of my slim stand isn't final, but it could be anything between 3mm and 10mm.

author: Brumby
author_rank: Unknown
timestamp: November 29, 2017, 02:04:21 am
content: There are a few to choose from - Google is your friend.How about something like this:http://www.futureelectronics.com/en/technologies/electromechanical/switches/tactile/Pages/7601396-JF15SP1C.aspx?IM=0

author: Brumby
author_rank: Unknown
timestamp: November 29, 2017, 02:30:41 am
content: You could also try using an actuator like this with your own custom "button"I can imagine a piece of sheet metal with "U" shaped slots, creating a metal finger that could be pressed, with the actuator underneath....

author: Brumby
author_rank: Unknown
timestamp: November 29, 2017, 02:34:29 am
content: Quote from: Decoman on November 28, 2017, 09:05:13 pmCertainly possible - but we are stepping into custom design territory.

author: Ian.M
author_rank: Super Contributor
timestamp: November 29, 2017, 02:58:39 am
content: You can get self-adhesive membrane keypads in a range of sizes and layouts off the shelf. They are very thin, but do need a slot for the connection tail to go through the surface they are stuck to at one edge. Also you need the right connector for the tail - it cant be soldered.However you'd get a much much better appearance if you consulted with someone with experience in touch sensor design and got a touch switch PCB made, with the buttons and silk-screened legends on the front as an integral part of the PCB, and the touch controller and a connector to the rest of your project as SMD parts on the back. The learning curve for concealed touch sensors is really steep - you *DONT* want to try to do it on your own, even if it isn't your first home-designed PCB.A third option would be a hardware hacked touchscreen Android tablet, with a custom app displaying an appropriately styled control panel. There are off-the-shelf solutions for hardware interfacing and control from Android, but if you need to do anything complex, you are probably looking at a MCU and a Bluetooth module paired with the tablet.

author: Brumby
author_rank: Unknown
timestamp: November 29, 2017, 05:18:06 am
content: Quote from: Ian.M on November 29, 2017, 02:58:39 amThis thought had also crossed my mind - but you beat me to it.

author: laneboysrc
author_rank: Contributor
timestamp: November 29, 2017, 06:34:56 am
content: How about those cheap capacitive touch button modules from China:https://www.aliexpress.com/item/10PCS-LOT-Touch-Sensor-Jog-type-touch-module-capacitive-touch-buttons/32451378348.htmlBy changing jumpers you can select on/off or momentary function, as well as active high or active low.You can mount them behind a thin plastic piece and they work just fine.

author: Decoman
author_rank: Regular Contributor
timestamp: November 29, 2017, 07:19:33 am
content: Thanks everybody. It isn't easy for me to just search for buttons when I don't know the terms, though it never occurred to me until today to search for "flat button".I am not entirely sure what 'momentary button' means, though I guess it has something to do with being mechanical.How would this button work? It looks similar to the one suggested in the post by laneboysrc just above. Photo probably show two pieces that were manufactured together.(Note: Advertised in the title as being something for Arduino)It looks to me that there are three solder joints on the top side of this chip.Looking at the photo at the webpage laneboysrc's linked, could the jumper be the two tinned soldering slots I think I see on the back side? Hm, maybe not.Could I just press the button once, to turn on the light, and then, press again, to turn the light off? Or must this thing work in conjunction with a programmable chip?

author: Brumby
author_rank: Unknown
timestamp: November 29, 2017, 07:33:07 am
content: Quote from: Decoman on November 29, 2017, 07:19:33 amMomentary simply means that the circuit is closed for a "normally open" switch (by far the most common) only when it is pressed. When you release, the switch goes back to being open. There is also a "normally closed" variation which works the exact opposite way.Push button switches that change their state with each press and hold their state when released until the next press are often called "push-on push-off" or "latching". Mechanically, these are much more complicated than simple momentary mechanisms.

author: Decoman
author_rank: Regular Contributor
timestamp: November 29, 2017, 07:49:41 am
content: A touch sensitive button would be preferred, thought this metal tipped button looks charming to me, which could be covered by a thin piece of styrene and hopefully the tip of the button could still be depressed so in order to work properly. Heh maybe too small. Says in the sales listing size = 4 x 4 x 2.5 mm, with no other information. Hm, on second thought I guess this thing below is more like a contact button with some other button material on top, rather than something you would put your fingertip on to press the button.Edit: Aaah. Brumby already showed such a button in a post above I think. I guess an 'actuator' could work for hiding the button beneath the surface, covered by some flexible material like a thin sheet of styrene.Interesting. I could ofc always make some kind of marking on the top surface to know where to press the button(s).Hm, I think the ideal solution for me, would be a 1mm flat button (seen above) but with an LED on it as well. Alternatively, an LED could/would be installed next to the button to signify if the button is powering a light or not.Edit: I found some even small ones for mobile phones:Looks like maybe less than 1mm in height. Maybe requiring some kind of pinned button cap material, that can actually depress the contact properly I am thinking.