Cheap as Chips Touch Switch

Cheap Touch SwitchesThose who (jokingly) complain that their wallets empty out every time they read my blog will be in heaven today… backlit and non-back-lit touch switches for as little as FIFTEEN PENCE !!!  It’s a winner!

Could these be the world’s cheapest backlit touch-switches? (Updated September 07 2017)

There aren’t any catches here – you can buy one at a time for slightly more – or 10 at a time – they have different colours etc.

My pal Jonathan introduced these to me a few days ago and I am SO glad he did!   So basically this is what you get – a panel maybe 20mm x 16mm (finger size!) and they have a 3-way 0.1” connector on the back – power, ground, output. Power is 3v6 to 6v. Operation is simple – bring your finger near the panel – it lights up and the output is on – move your finger away, it goes off.  If you want momentary action there’s a tiny pair of solder links for that, too.  The proximity switching works through plastic – maybe 3mm or more?

VideoSoundNow that last point is really important as these really are not too much use on their own, not that pretty and with a band at the top – but they do light up evenly and brightly and that’s the point – with a case with some kind of legend, maybe a negative sheet with shapes – you know, my friend and I were responsible for the world’s first video jukeboxes (no, really, we were) and one of our first designs was a Perspex front with a large negative behind it – black with clear track titles etc… at the front we had large amusement machine-type buttons.. If ONLY these things had been available at the time !!!!

Sorry the picture is so crap, this is pre-digital camera, pre-Internet. But you can see the backlit negative. The mechanical buttons could have been completely replaced with touch areas.

Today, I’m thinking – negative with down (left triangle), menu (menu) and up (right triangle) – three of these on an ESP and some kind of display (the cheap SD1306 OLEDs at under £3) and you have a marvellous menu control for whatever – lighting, heating, house control – you name it. Just a little visual imagination… or maybe if you’re lucky enough to have a tiny engraver – engraved in a plastic front panel deep enough to let the light through – the list goes on. See what can be done with star-trek style control panels.. This example of a backlit panel got me fired up…

Want to take my Jukebox to futuristic extremes – check this out – stunning – and you could do this with these touch panels, a bit of plastic and a negative.. for VERY little outlay…

Oh, you want to see these in operation – I made a video and near the end of this short video where I talk about other stuff in the postbag…  and here is the cheapest price I could find – including postage (well, the postage is free) 0.767 pence each…  so many possibilities…

Even Cheaper

HOWEVER - as we look through the adverts it turns out there is a similar non-backlit version which is a lot cheaper.  Do your own backlight? Edge lighting?  Check this AliExpress link out.. Worth a play?

Cheap touch switchesYes, I have a pack of 20 of them and they work a treat. Stuck behind a plastic panel you can use them as simple switches or toggles. Normally the output is low until you touch (or get very near to) the switch – but this can be inverted by shorting junction A (and this is necessary if you want to use them with GPIO2 on an ESP8266 – well, mine anyway as they don’t like having GPIO2 low on power-up).  As these work out at only  a few pence each and avoid the need for input debouncing software, they are WELL worth considering.

wall displaySo for example – the wall display – here is my QD-tech-based wall wifi information panel. See that space near the button under the display – well, I’ve fitted one of these touch switches (glue) on the inside – as above with the A link shorted (essential) – to GPIO2.   See that TIME section up at the top – well, now when you touch the display, the SET heating temperature takes over that area for a while – repeatedly touching the box rotates the temperature up to 27c then back down to 14c and back up again… hence forming a dust-proof control for heating with no extra holes and only a few pence cost. Works a treat - check out the video - https://youtu.be/ac44RjPDHa8

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68 thoughts on “Cheap as Chips Touch Switch

    1. Oh I am SO glad you mentioned this - BECAUSE the one thing I don't like or would like improved is the ability to be normally ON... ie for doorbells etc. now - YOUR board (which does not say if it is proximity - but let's assume it is.... has an option for normally on or off.

      SO - out with my microscope... chip says 02a-4 preceded by circle with 2 lines in it... not remotely the same or so it would seem.... in your board pins 1 or 3 get shorted to pin 2... for normally on or off.... on mine -
      pins 2 and 3 shorted make for momentary operation....

      I was hoping you were right as I'd really like normally on...

      Any thoughts?

      1. If you notice there are 2 jumper slots. One is for toggle or switch functionality and the other is for "high" or "low" sensitivity. I have them installed in my house inside "glass" type wall switches that also house ESP and a small Solid relay. Where is a single light I use the "high" sensitivity setting while on a couple of occasion where I have more then one touch sensor within the same enclosure I use the "low" sensitivity. "Low" sensitivity is near the distance showing in your vid. "High" sensitivity is almost twice as long

        In this pic of a sensor similar to the one on your vid :

        http://ae01.alicdn.com/kf/HTB1ipSgRFXXXXbBXVXXq6xXFXXXp.jpg?size=90838&height=800&width=800&hash=67a50526fe5912f7411701bafc7c5091

        I see a blank pad that might do just what you want. Is this the case with the one you are holding ?

        1. Yes. The 2 pads on this one can be shorted to give you momentary operation - but that's the only option I can find - i.e. toggle - or switch. I'd dearly love to have push for off, release for on - for night indicators - but hey ho, lots we can do with them as they are.

      2. Ok, I checked and mine will definitely not invert operation....

        Anyway, so now we have the cheapest NON-LIT UP touchswitches - but not from your supplier Dmitri - AliExpress- FIVE for £1... so maybe in cents a little higher than that. Cheaper prices for higher quantities.. I've ordered 5 to have a play with... to see if they are proximity - not a lot of use if not - but at that price it is worth a play.. here's the link https://goo.gl/xKzMjA

        1. Cool !!! Free shipping is the main game in the small money gadgets. 🙂
          BTW I had some (very sporadic) mishaps in the unit I installed in the utility room when the 3-phase 27Kw heat pump kicked in. I see the lit version you have on hand is advertised as "Strong anti-interference" so this might be a plus (?)

  1. Hi All,

    I've just installed some cheap wall mounted 433MHz RF switches (powered by a tiny 27A type 12v battery). These are about £3.50 from Aliexpress. They look a bit cheap but they're doing the trick for me at home where their signal is picked up by an ESP8266 running OpenMQTTGateway which translates the RF signal to a message payload on an MQTT topic. This gives me a 'girlfriend compatible' manual override for lighting and heating control etc.

    I intend rolling out some more of these and will provide photos and details when I'm back home next week if there's any interest.

    I mention them as they worked out of the box and all programmed into my Pimatic Home Automation system in a couple of minutes. I'm also playing with 433 MHz window/door reed switches and am awaiting delivery of some PIR sensors and smoke detectors that also work on 433. I prefer ESP/wireless stuff as it's more reliable and gives better RF coverage but I'm getting quick results and additional functionality really quickly and cheaply with this 433 stuff combined with the RF to MQTT gateway.

    Photo attached shows the internals of a 3 button switch (they do a 1, 2 and 3 button model). There's facility to solder in a better antenna if necessary at the top of the board. The push panels for the switches hinge down over what you can see here and click in place. They come with self adhesive sticky pads and type 27A batteries. The sticky pads say '3M' on them but I'd imagine that's just the QC sign off by a hungry chinese man rather than the real thing. Given the light weight of the switches, they seem sticky enough though ...

      1. Certainly! Links as requested.

        Open MQTT Gateway
        https://github.com/1technophile/OpenMQTTGateway
        This translates from 33RF/Infra Red/BLE to MQTT, and the other way round. I've got it running on one of my favourite Wemos D1 Mini ESP8266 boards with cheap 433 RX/TX modules connected to D1 and D2 pins.

        Cheap 433 MHz wall panel remote transmitters (1,2 and 3 button)
        https://www.aliexpress.com/item/433Mhz-86-Wall-Panel-Remote-Transmitter-1-2-3-Button-Sticky-RF-TX-Smart-Home-Hall/32808813754.html

        Cheap 433 MHz 'door bell' button.
        https://www.aliexpress.com/item/Wireless-ding-dong-door-bell-button-433mhz/32488121143.html

        The door bell style one is more substantial and feels nicer to use but doesn't look as tidy. It's designed for a panic alarm or similar so you'd need to get vinyls made up to cover the alarm symbol if used for something else.

        I've got a few of each of the above and I simply press each button, see what code comes up on the MQTT topic and then implement a 'rule' triggered upon that payload for subsequent transmissions in my Pimatic home automation system. I then wrote a bash script called 'sendRF' which publishes MQTT to allow me to trigger the outbound RF on the OpenMQTTGateway for emulating button presses for switching Energenie sockets and the like.

          1. Strange...

            My actual wireless doorbell at home (not sure of spec as it was from my pre-IoT days) didn't register on any of my 433 kit but I have 3 of the above 433 door bell switches from Aliexpress and they all chirp out nice working unique codes every time...

            1. Today I received some 433 MHZ PIR sensors. They look well built (better than I was expecting from Ali Express). In 30 seconds I had one hooked up to my home automation system and now I have automatic light switching (when at home) and automatic intrusion alerting when I'm not at home. My "at home" logic works on a check of a virtual switch as a manual override and an "nmap" linux command searching for the MAC address of my mobile phone or 'er indoors mobile phone on the home WiFi network. If neither of our phones are connected to the WiFi then we're probably out.

              In the old days you had to cable up all this kit but 433 makes speed of installation and availability completely different.

              I think I buy too much cheap chinese IoT stuff...but it's fun playing with it. I'll provide links to the PIR sensors if anyone's interested. I'm awaiting delivery of 433 RF smoke detectors too...

                1. Link to the YobangSecurity 433 MHz PIR sensors from AliExpress

                  https://www.aliexpress.com/item/hot-sale-433-Mhz-wireless-PIR-motion-detector-for-home-security-alarm-system-PIR-sensor/32731322511.html?

                  £6.87 each, free shipping to UK

                  They came with 9v battery fitted and screws and a angle poise mounting bracket. Quality seems okay but I'm interested in how long the battery life is. There are various adjustments apparently inside to change some preferences but I've just installed 2 at home with stock settings for now.

        1. With the wall panel transmitters, do you get a transmission for both the ON and OFF states? I have a 433Mhz door switch but it only sends for open so there is no way to know if the door is closed again.

          1. Hi Dave,

            The 433 door/window switches I have from AliExpress only emit a code when the state changes (door open, door closed again) but you DO get a different code for each state. There's a 3rd code emitted if an anti-tamper switch is triggered (opening the case to get at the battery - quite a cool feature).

            I've only got one of these in live use - at my holiday home to switch off my dehumidifier if the window is opened - and to revert back to previous state when the window is closed again. I haven't spent enough time fine tuning the installation of the switch and I can't say it's 100% reliable as I've had some dropped/missed codes which have then caused my RPi based Home Automation system to get out of sync with the state of the window. It's pretty good though - not unreliable enough to warrant me to remove/replace the setup but equally not something I'd install anywhere mission critical.

            When I dummy it up on the desk and move the magnet away from the sensor and then bring it back, it behaves beautifully, sending the appropriate open/close numeric code as required. I'm not sure if its a de-bouncing issue caused when opening or closing the window quick/slow/differently. If it was mission critical stuff, I'd recommend a hard wired window/door switch.

            I'm really pleased with the wall mounted push switches that I mentioned before (available in single, double and triple button configurations - with unique codes per button) only emit a single code for each button - i.e. not an ON code and an OFF code just a "push to make" code. These have been really reliable and I have rolled out loads of them all around my house and holiday home and use them for various things - plus the 'doorbell' style 433 remotes and a couple of 433 PIR sensors. I've gone a bit '433' crazy but it's really improved the human user interface so that I can switch on/off lights/devices from a) software rules b) web interface and c) the old fashioned pressing of a wall mounted button - whereas earlier configurations frustrated 'er indoors and she started unplugging stuff in frustration!

            1. Thanks Darren. I've order 3 of the 3 way and 2 of the 2 way to try them out. I have Enocean modules and use some 3D printed rockers but the hinge pins keep breaking so they become very annoying to use and not good for any WAF. I hear lots of expletives from the wife on the odd occasion so a more reliable option would be ideal.
              I'll build up the receiver whilst I wait for the switches. Still on the lookout for door sensors with OPEN and CLOSED states.

              1. Hi Dave,

                These are the door/window sensors that I have:-

                https://www.aliexpress.com/item/433mhz-wireless-window-door-open-alarm-sensor-gap-detector/32402085702.html

                At £3 / $3 you could give them at try as, with the correct installation they do give a different code when opening and when closing but it's a momentary signal each time the state changes - it doesn't repeat the signal (otherwise the internal battery would go flat, I guess). Given the price, you could try one but equally you could build a more reliable one based upon a reed switch or hall effect sensor and have it hard-wired into an ESP8266 or something and then code it so that it sends regular repeat confirmation signals/messages based upon state. I don't have a mission critical need for one and only really bought them out of for R&D / curiosity purposes!

                I'm worried that I've caused this topic to wander waaaaay off Pete's original subject of his funky wall switches. If Pete would like to start a generic '433 MHZ IoT sensors" thread, we could continue the subject there as there's quite a wide range of devices out there and they've gained a new lease of life now that I have a bi-directional 433 to MQTT gateway to link them into 'modern' projects.

              2. One other thing...with the 433 wall switches if they are the ones I bought they have a solder pad drilled on the pcb to attach an external antenna to. I found that this increased the range quite considerably and the antenna wire still had room to hide inside the switch so nice and tidy looking when put back together

                1. I got the door switches but I get hardly any range from them to the RF receiver. I've located the RF receiver away from the Wemos D1 but get no more than 3 meters if I am lucky.
                  What RF receiver did you use? I think I need a better quality one with a SAW filter.

                  1. Hi Dave,

                    There are two types of receiver module commonly available, one is slightly more expensive and has a better range but for both types, an external antenna is vital. There are various article on the internet discussing length of (single core, not multi-strand) wire antenna and some people use a straight length and others use a longer wire, coiled depending on what fraction of the wavelength (1/4 wave etc).

                    For my 433 RF wall switches, I solder a wire on the transmitters too (and still manage to conceal the antenna inside the plastic casing of the wall switch).

                    With the door sensors, I've not dismantled them to see if the PCB has a solder pad for an external antenna although I've not found it necessary. My holiday home is a tiny chalet so I've not experienced any range issues but at home where I need to cover a larger area, I run two identical RF gateways to give better range - but both gateways have external antennae for both RX and TX.

                    These will win no prizes in a beauty contest but work great for my home

                    1. You can also buy little pre-formed coil antennas for 433 RX/TX (some modules come with them). You'll need to experiment with what works best for you - if you can get one of the small coil antennas added to the door switch and a (longer, external) wire antenna on the gateway RX you should be good.

                      These are the more expensive, apparently better, modules ("Superheterodyne 3400") :-

                      https://www.aliexpress.com/item/Excellent-Quality-433Mhz-Superheterodyne-3400-RF-Transmitter-Receiver-Link-Kit-For-Arduino-ARM-MCU/32801948732.html?spm=a2g0s.9042311.0.0.BqPYuZ

                      If your units are the smaller, cheaper type, you may find that these ones, above work a bit better but the difference that adding an external antenna of the correct tuned length makes is significant.

    1. sorry for the (maybe) dumb question?
      having more than one of those units, how the gateway can discriminate which button of which unit has been pressed?

        1. thanks!! So this code is embedded in the "frimware" of each unit... let's hope to be lucky and not find 2 with same code 🙂

          1. Well with 7 digits - assuming they are decimal and assuming Darren didn't mean 7 bits - it doesn't take a rocket scientist to figure out what are the chances of coming up against the same number twice...

            1. Indeed Peter, unconsciously my engineer mind visualized that answer as 7-bits so I translate Darren's reply as 0-127 😀

  2. Hello Pete,
    Apologies if I missed it in previous post, but can you provide a link for the case you are using?

    Cheers,

    Alex

        1. Oh that one - the really good, cheap one with grates on the side, ideal for thermostats, that everyone would like.... they stopped selling them.

          They were 70mmx70mmx20, with side ventilation and just a few ££...

          This looks like an alternative but is deeper (28mm) and VERY expensive for what it is.

          http://www.ebay.co.uk/itm/1-St-Gehause-universell-X-70mm-Y-70mm-Z-28mm-beluftet-ABS-grau-/172757227356?hash=item283922175c:g:SwgAAOSwH09ZLxCx

          Decent looking cases - especially wall mounted cases at a reasonable price remain a rarity - it is as if the plastic designers of the world have no taste at all.

          This one is bigger - but I think it would work nicely on a wall...

          http://www.ebay.co.uk/itm/New-Plastic-Electronic-Project-Wall-mounted-power-handheld-box-with-cooling-hole-/291031077101?hash=item43c2cdd0ed:g:fuUAAOSwrddY7byR

          1. I bought a couple of batches of these little 80x80x27mm plastic housings from AliExpress which I use for temperature sensor / ESP8266 devices

            https://www.aliexpress.com/item/4-pieces-80-80-27mm-customizable-pcb-enclosure-electrical-plastic-housing-box-humidity-temperature-sensor-switch/32684746428.html?spm=a2g0s.9042311.0.0.Y2HApB

            I don't think they look too bad and they work out about £3.60 each including shipping but like a lot of china kit, every time I buy them I pay a slightly different price.

  3. Ok so the cheap touch switches (non-backlit) turned up... and I've been testing them. They do not seem QUITE as sensitive as the backlit versions - when run through plastic cases but they do work well and they are CHEAP.

    I really don't understand the logic of the design however. They have a bright red LED on the back which reacts to the switch being touched. It is utterly useless as it is on the back and won't be seen in operation!!! It would have cost no more to have a simple hole in the board and reversed LED so that the light shone through the FRONT.

  4. So you have choices - normally open - normally closed (ie inverted output) - that's one lot of links - the others are for latched or non-latched operation - by default with all links open - they are non-latched. I think the larger pads are for another totally useless LED 🙂 I guess if you could put a rectangular tube slightly larger than the board and fasten all of this to a red frosty perspex panel it might be possible to use the onboard indicator as some kind of frame light. Better to remove it and use another led on a lead I think.

    But I'm being picky - these are really cheap! Bearing in mind that mechanical alternatives to a controller usually involve debouncing software - they could make for very simply switches. AND... they cost me under 20p each inc post.

    1. I'm taking that back about it not being so sensitive - after a short delay it seems to have become MORE sensitive - too much in fact - in that putting it on the back of a plastic container will in itself trigger the thing.... sensing distance is 9mm

  5. Hi Peter.
    Thanks for sharing these lovely things.

    I use it behind my magic mirror in my bathroom
    Have a pi & mqtt to turn on my ventilation system.

    One small disadvance is that they don't work bidirectional.
    So if mqtt makes the gpio pin low the led doesn't turn off.
    Maybe somebody knows a work around.

    Thanks

    1. What if you used another GPIO pin for the VCC. When dropping it low, it would reset the switch, would it not? Still waiting on mine to arrive, to test the theory. Of course, it consumes another pin.

  6. Just received backlit switches ordered after reading this post, and they are nearly perfect! Thank you Peter for sharing your discovery. My only dream to make these switches absolutely perfect is one extra input pin, so the switch can be used as indicator. This would allow to build really cute SpaceTrack-like dashboards. Maybe one day I'll remove front cover and try to figure out is it posible to solder input wire to LED....

  7. I purchased the cheap 20 piece set from AE. https://goo.gl/4Xsb6L . They arrived with from what I can tell is the wrong chip on them. The marking is 8233 on the chip. When I plug them into the arduino 5V/gnd and a data pin, they get very hot quickly and burn out. Not really sure how you could manufacture the wrong chip on the board and have that pass through even the worst QC processes.

    1. Hi Not sure if its the same problem but I have just had a batch of 20 of these non backlit switches and of the ones I have tested they have all failed. As soon as you power them up the LED is very bright (3.3 or 5V) and the sensor pin shows a continuous high reading regardless of attempts to change the state of the switch. No noticeable overheating however but the chip is marked 8233. I am just waiting for the repeated "send a video" requests but at least they were cheap - on the other hand the backlit switches work very well.

      1. Oh, so you've spotted the cop-out "send a video" messages!! Erm, well, I bought 20 of those chips and I've only tested the first one but I don't get that issue - I get either too insensitive - or if you leave it on a while, too sensitive... but they work. Had one on for a week now...

    2. Unfortunately I bought the same with the same problems. None of them usable.

      I identified the problem: the chip is soldered upside down.
      By the chip datasheet: PIN2:GND and PIN5:5V On this product: PIN2:5V, PIN5:GND. So if you connect it it burns out because of reverse polarity.

      1. For what it's worth Aliexpress did give a refund on the non-lit switches after I had to produce the most pointless video (of a swich not working) - but at least it gives reassurance that you can trust their refund guarantee for more expensive items.

        1. They all do this now "can you please send a video" - I think it is a standard phrase used by companies who don't speak a word of English!!! Most annoying when it isn't even remotely appropriate - in your case a simple photo would have sufficed. Nice to know you got a refund and for the record I use AliExpress all the time without issue - that's not to say there will NEVER be an issue of course. Hopefully you'll get some workers next time. At the price I think these have GREAT potential but you would not expect them to be hand-tested at that price 🙂

  8. I planned to use 4 of these alongside a 320x240 tft display and they worked well in a freestanding mode, but when I placed the whole lot behind a 3mm perspex front they started to switch on and off randomly. Not sure what is going on?

    1. Hi John,

      You may need to position the boards approx. 3-4 mm away from any kind of plastic sheeth. These are capacitive sensors. That means the higher the sheeth's permittivity the more they start triggering the sensor already.

      It could even be, that you have to position them so far away from your sheeth, that you can't trigger them anymore by touching the surface. Use a sheeth with a lower permittivity.

      1. For reference I am using ONE inside a plastic box... next to a QDTECH display and held in place with glue gun glue and it works a TREAT.

        I wonder if proximity to each other might be having an effect? Try disconnecting all but one to prove or disprove this?

  9. How is the light controlled? Directly on the board?
    I would like to use it for a sonoff and control the sonoff via MQTT, too.
    And then the light is off or stays on when its switched via mqtt.

    1. The light is connected to the output. Personally I have disconnected (unsoldered) mine and added my own light - taken to the other rail... The reason I say this is I have mine attached to my only remaining ESP8266 input GPIO2 - and that does not like being LOW on power up.... so I have link A shorted so the switch powers up HIGH - that unfortunately means the light is ON and goes OFF when you touch it - which is not really useful - clearly it is also on the wrong side of the board on the cheap switches - so better perhaps to disconnect.... and do your own thing with a resistor and LED? Only adds a couple of pence?

  10. I have tried different materials for the front "touch" area. Glass, perspex, plywood etc. They will all trigger the switches when in close proximity. It also seems that my my switches which are closely spaced do interfere with each other. They also all seem to have different sensitivity. So each switch needs to be backed off the front panel until it just "untriggers" and then fix it in place. I need to experiment some more.

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