Heltec Touch Module - Latching Capacitive Touch Switch

I spotted an interesting looking Capacitive Touch Switch module on the isctation.com website and asked them if they'd send me one so that I could take a look and have a little play around. It's a cap touch swtich, with built in LED and light spreader/diffuser. It'll work through a few millimeters of plastic and it struck me that it's a great way of desiging switches into 3d-printed enclosures without having to worry about incorporating switch cut-outs with the associated problems of 3d-printing overhangs.
Here's a link to the product:
www.icstation.c...
Here's a link to the Chinese datasheet. If you download the PDF and then Google for 'google translate pdf' you'll get to their PDF converter which will take the PDF file and give you a text-only english version. I got some weird SSL errors the first time I tried to download the datasheet, but it worked OK after a retry.
Datasheet (Chinese): www.heltec.cn/w...

[@CustomMaDe-eo2wx]

Jeah, they are really nice. Did a bit of testing with them too. If you change them to a simple pushbutton type they’ll just light up as long as you push them. If you want them to light up unpressed you can give some power on the OUT Pin and they light up. Just make it less V then the signal they give when pressed. If you light up the led via 3V on the Out pin and switch 5V with it, this 2V difference are enough for an Arduino to read the input. I have a version here, called colorful , I hoped that I could programm it somehow but it just changes colors in a rainbow pattern and this looks not so great. Ordered a bunch of blue ones now

[@BenjasUberHobby]

I so could see a sci fi computer panel lit up with those things! Thanks for sharing :)

[@ThingsWhichArentWork]

Thanks Benja - One day I will make the mother of all automation systems for the greenhouse and it will have dozens of these switches. Cheers!!

[@BenjasUberHobby]

Can't wait!

[@RWBHere]

Very nice. Thanks Jim. Now we're off to read the pdf, to see what it can switch.

[@RWBHere]

Update: The link is now dead. (27th April 2018.)

[@marekl8805]

Nice little switch, I got one myself. But as of now, the Heltec website does not have the datasheet published.

[@MihaiDesigns]

Pretty cool module for 3D printing 😀

[@JuliansRandomProject]

Looks like one could easily solder in any color SMT LED they'd like. Definitely gonna add a few of these to my arduino kits. Thanks!

[@ThingsWhichArentWork]

I wish they did a version with an RGB led in there... It would be nice to be able to change the colour in software whilst still having the touch switch function provided in hardware... Cheers!!

[@FlyingShotsman]

Neat item, Jim. Thanks for the heads up. It would be interesting to see a little test of the maximum panel thickness that allows reliable switching. BTW, they're available on AliExpress from multiple sellers for as little as US$1.38 ea., with free (slow) shipping. Search for "httm". Also a few on eBay, but no bargains.

[@ThingsWhichArentWork]

Hi FlyingShotsman - Sorry for the delay in coming back to you... Sometimes life gets busy... I found that they worked without any kind of problems through 3mm of 3D-printing... I'd guess that you could push it up to around 5mm without loosing the ability to activate the switch. Cheers!!

[@DansKoiPond]

Good for outdoor applications where you need to turn something on or off. The switch can stay inside a waterproof box etc

[@ThingsWhichArentWork]

That's exactly what I was thinking. Cheers Dan.

[@easytouch812]

I just wanted to thank you for entertaining me for 3 minutes and 22 seconds basically watching you do nothing but turn your little switch on and off I really hoped to be showing how to convert this switch to momentary you mention removing a resistor and show us your fingernail

[@OrbiterElectronics]

Thanks for showing these Jim.. They look really handy.. Off shopping now :) Cheers mate John

[@vladhristov2316]

Hey Jim! Thank you for the video, hopefully, you will see my comment and respond. I have a question, might be a little bit of stupid, but I have designed a schematic and in the last minutes I needed to plug this sensor to an analog pin at ESP32. Do you think there is a possibility to turn ON/OFF the sensor too thru the signal output pin? Thank you!

[@ThingsWhichArentWork]

Hi Vlad - I think the module will require more power than an ESP32 could provide. I think you can only do ~5ma of current with ESP32 outputs but the module will need more like 20mA. You could add an extra transistor to the output pin to provide some more current capability though. Hope that helps. Cheers!!

[@SrTracz]

Hi, I am working on a project for college and I will use the touch sensor but I have a problem, do you know if it is possible to turn the sensor on and off from a microcontroller?

[@FesterWerks]

Oh man, a Star Trek control console for the garden. Sweet :)

[@ThingsWhichArentWork]

Thanks Marc - The modules are certainly a great idea for any kind of waterproof project. Cheers!!

[@PeterScargill]

Absolutely - sheet of perspex, sheet of negative film, load of these.... and you're off - BUT right now they are completely OFF until they are ON - if you get my meaning, would be better if they could be DIM when off but I'm not seeing how to do that.

[@owilline3]

hi what connectors can i use to connect this touch sensor to a small dc motor and 23a battery?

[@bryngerard4334]

They look grand! Possibly a bit overpriced but I imagine they will become widely available because they look so cool and simple to use.

[@ThingsWhichArentWork]

Hi Bryn - They're available elsewhere at a lower cost... I'll be buying myself some more when I decide what project I want to use them for. Cheers!!

[@bryngerard4334]

Jim Conner Ta Jim, sorry about the novelette re: my exploits in Hydroponics and thanks for the tips :)

[@nanstv]

Hello. Did it work behind a plastic board of 5mm thickness ? Or we need to touch directly the component ? Thanks

[@onlinecircuitsimulation8774]

Whats is the thickness? If i use 1mm thickness will it work?

[@ReevansElectro]

The data sheet link doesn't work. Do you have another link or a copy of the data sheet I can access, please?

[@victoriamotion7980]

You can find a capture from 04.01.2017 in the web archive tinyurl.com/HTTM-Capacitive-touch-module.

[@creativethinker6064]

what an idea i like it keep it up! ❤

[@niknik2308]

Hi jim, i Think the ones i ordered will not contain the resistor, i want it to act as a doorbell button , touch on, release off, do i need the resistor or i dont need it?

[@grumpystony]

Can the switch be set up to output 12v or ground. I would like to try having it trigger automotive relay with ground.

[@wosagichnich8869]

Hi, the link to the datasheet is www.heltec.cn/download/Touch_Moudle.pdf

[@farmaforpresident8138]

Sorry, do you have that pdf? it seems to be missing

[@Iggy89]

Hi Jim, I removed the resistor but it still latches.. It doesn't seem to change anything.

[@longtaoyu]

Dear Sir i am one worker of Heltec Automation in China ,we think your video is good,Could we use this video to as our Advertisement video?

[@ThingsWhichArentWork]

Hello Iongatao20150101 yu. Please go ahead and use my video for your advertisement. I am totally happy for you to use my video however you like and do not require any payment or accreditation. Having said that, if you have any other products that might be interesting for me to take a look at, I would be more than happy to be sent items in the post and may even make another review video for you in the future. Many thanks. Cheers!!

[@kirkb4989]

Did you publish the 3D printed model for your "enclosure" anyplace?

[@AM-yw4ld]

Can we program the color as they are available in rgb?

[@phuuuur]

Hello mr Jim Conner! I'm wondering cause i am going to make a auto feeder for my pet! It's feeding them cockroaches and i want something like this to tell me when the cockroach is moving onto the desired place where it will drop down! Does it work with objects or just human touch???

[@ThingsWhichArentWork]

Hi Mads Rinker - The switch works by detecting a change in capacitance as your finger gets near. The difference in capacitance between a human body and the copper trace on the PCB is pretty huge. I don't think it is likely that it would be able to detect something as small as a cockroach, but it's not something I've tested so I could well be wrong. I would think that some kind of optical break-beam sensor might be a better approach for detecting the cockroach. Cheers!!

[@phuuuur]

yeah i was thinking IR but this button would add some flow to the thing ;) Thanks for the quick response

[@chanchopanza]

hi ,do you know if it can it be change from high output to low ?

[@gaets04]

can it make a solid State Relay come on and off ?

[@HandyKindaGuyUK]

Does this work through glass??

[@sandhyaagrahari8258]

How to connect of battery

[@vivzbravo]

Hello Jim, a small help, I have watched your video and got one of the same touch sensors for my small project. Using the touch sensor I want to connect it to a 5V relay switch so that it can turn on a light bulb on 220 VAC line The touch sensor has been supplied a 5VDC, but this whole circuit does not turn on the bulb, although the touch sensor light turns on / off when touched. Could you please help

[@ThingsWhichArentWork]

Hi Vivek - The output on those heltec modules will only handle loads of a few milliamps.. I'd guess around 20mA... but the 5V relayt will likely need more like 100mA to energise it's coil. You'll need to add a larger NPN transistor onto the output to handle the higher current. Take a look at the 'On/Off motor control' section on this webpage... www.electronics-tutorials.ws/io/output-interfacing-circuits.html ... Please note that the reverse polarity protection diode across the relay coil is very important because otherwise ther relay coil can generate high voltage spikes when it is switched off which will quickly destroy your NPN transistor. Hope that helps. Cheers!!

[@vivzbravo]

Thanks Jim for your valuable inputs

[@kintara58]

The datasheet I found says max output current is 500mA (hacktronics.co.in/touch-sensors/httm-series-illuminated-capacitive-touch-switch-button-module-27v-6v)

[@aladdinsr4567]

Halo, can the switch direct drive lamp 5v (usb), max current ??

[@ThingsWhichArentWork]

The max current that the switch module can handle is just a few milliamps - OK for lighting an LED, but for more that that you'd have to add a transistor on the output to handle the higher current that the lamp needs. The transistor circuit you'd need to add on is called an 'Emitter Follower' - Here's a reasonable looking link about Emitter Followers that google just gave me. www.learningaboutelectronics.com/Articles/Emitter-follower-circuit.php - Hope that helps. Cheers!!

[@aladdinsr4567]

@@ThingsWhichArentWork Wow, very happy for your response. Thank alot Jim. Visite my channel, I just start upload last week.

[@saifilifeblogs]

Whats name this switch

[@georgeeden5835]

A shame you can’t have white and blue or a rgb button so you can then have other buttons backlit while one is pressed.

[@victoriamotion7980]

RGB variant is available. Unfortunately I couldn't find any information how to control the backlight color in the official datasheet nor anywhere on the Internet.

[@johnsalmon735]

@@victoriamotion7980 I am looking for the RGB variant can you post the link where it is available please - Thanks You in advance

[@victoriamotion7980]

​ @John Salmon Sure, on this video is shown the color fading heltec.org/project/touch-button/. And you can get them e.g. here www.aliexpress.com/item/32884275129.html, variant "Colorful". I haven't play with them yet, though...

[@victoriamotion7980]

@@johnsalmon735 P.S. I have found this official forum thread community.heltec.cn/t/rgb-touch-module-color-select/2912/4, where is mentioned the color LED SW and HW driver used in this button. None of this I've tested (yet).

[@D-One]

Can it be used as a momentary switch? only on when touching it?

[@ThingsWhichArentWork]

There's a jumper position on the back that lets you switch between momentary or latching behaviour. I didn't find out about it until after I'd made this video, and haven't tried it for myself, but it is theoretically possible for it to operate as a momentary switch. Cheers!!

[@ricardomoyano5081]

@@ThingsWhichArentWork Hi there! I´m trying to change it as a momentary switch but no success. I tried to jump those 2 tiny points of soldering on the back, but nothing; I also read that soldering a 10K resistor but I don´t know where...If you have any link or plans , I really appreciate it! Thanks!

[@ThingsWhichArentWork]

Hi Ricardo - Sorry, I'm afraid I don't have any more details than you already know. I thought that there was a datasheet on the Heltec website, but they seem to have removed the touch module from their shop now. Sorry my friend. I'm afraid I can't help. Cheers!!

[@ricardomoyano5081]

@@ThingsWhichArentWork Ok thanks for your quick answer! Cheers!

[@ricardomoyano5081]

Found it and it works, kzbin.info/www/bejne/jIqVhqV5j8aCfM0 , those tiny points has to be soldered ! and voila! momentary switch!

[@fuhk]

Are you still on here?

[@ThingsWhichArentWork]

I'm still alive.. but haven't made any new videos in the last few years.

[@fuhk]

@@ThingsWhichArentWork thanks for replying. I wanted to ask you about schematics for the 3D printed holder for a protect I’m working on. But I think I’m going to test plexiglass tomorrow to see if it works.

[@ThingsWhichArentWork]

@@fuhk If you need any of my designs, please give me a ping. I never delete anything so I'll definitely have them kicking around somewhere. Good luck with your project. Cheers!!

[@harrydevokone9505]

Where have you been? :)

[@ThingsWhichArentWork]

Hi Harry - I've been busy lately with... buying a new car, playing with the new car, fixing the sliding gate, selling the old car, fixing the shower, getting a new central heating boiler installed, getting it working properly and other boring life stuff which wasn't really interesting enough to go on youtube (except for fixing the sliding gate... that would have been a good vid, but I didn't think to get the camcorder out at the time). Also been playng around with a new tune to go with the next video (whatever it may be)... I'll get around to another greenhouse update soon, and I've still got a thing from icstation that I need to have a play around with... Cheers!!

[@harrydevokone9505]

Great, looking forward to it!!

[@projecthivemind3239]

Hi. What kind of a heating tool was that used at 0:53?

[@mikadodrrr9720]

ProjectHivemind it’s a heat gun

[@mikadodrrr9720]

You can get one online maybe Walmart and definitely at craft stores like ax moor or micheals store

[@topsecretevents6182]

Out of stock sept 2018 :(

[@carlossepulveda663]

Alguien sabe de un tutorial en español?

[@maneshs9985]

Can i use this switch to on/off 12 v dc led strip?

[@ThingsWhichArentWork]

Only if you add on a relay or transistor to handle the load.. The switch itself just gives out logic levels to interface with a microprocessor - It can only handle a few milliamps at 5 or 3.3v.. Cheers!!

[@maneshs9985]

Jim Conner okk..can i use it for 5v led stirp directly without adding any relay

[@ThingsWhichArentWork]

I'd be surprised if you can pull more than about 20mA on the output... You'll be able to light up 5 or 6 LEDs, but not much more than that. Adding a transistor onto the output is easy though... Check out the 'Digital Logic Transistor Switch' about halfway down this page... www.electronics-tutorials.ws/transistor/tran_4.html .. Hope that helps. Cheers!!

[@maneshs9985]

Thank you jim...but if i give 5v1amp input...the switch will get damaged or not?

[@ThingsWhichArentWork]

The switch will not be damaged. The switch uses hardly any current.. (about 5mA for the led backlight IIRC). Even if you used a 1000amp power supply, the switch would still only consume the 5mA that it needs. Cheers!!

[@demiansmith]

Datasheet (English): resource.heltec.cn/download/Capacitive_touch_module_V0.2.pdf

[@bdg5727]

Thank you!