flee-mo™ touchless switch prototype model

flee-mo™ touchless switch prototype model


Non-contact button for hygienic UI, inspired by “a touch”, powered by invisible infrared light



Touch-free UI without accumulate grime, bacteria and viruses

icon-eye-catching effect.png


Eye-catching effect and decorate the attachment surfaces


Custom design

Control a variety of devices: incandescent/fluorescent/LED lamps, solenoid valves,...


Costs less to run

Approximate 1 kilowatt hour per year, or average $0.1 per year


The name flee-mo™ stand for the term “fleeting moment”, to merry memories. Hopefully, with flee-mo™, every fleeting moment will be unforgettable...!

December 25, 2014

I went to the Exodus movie with my friends at CGV Hung Vuong Plaza. We waited the elevator on the first basement floor. When the elevator ascended to ground floor, a lot of people stepped inside, the cab was crowded. A girl stood in front of me, I recognized she was CGV cinema’s staff by the special uniform she was wearing. With soft natural makeup and high ponytail, she looked so pretty!

When the elevator stopped at the 04th floor, the doors opened and many people stepped out, she had moved back a bit so that they could squeeze out. Just then, incidentally, I touched… “her bottom”. Oops! I froze up and felt really awkward, although this was an accident!

After that, the cab was quite uncrowded, she moved to stand opposite. I caught her eye, she was stealing a few glances at me. But I had neither made eye contact with her even for a second nor looked at her name tag. Because I still felt really shame with that “touch” and I also wondered whether she would ever be getting angry or not? I looked elsewhere, at the elevator fixtures, I was suddenly inspired by the spark of idea: “Why have we all used push buttons for elevator fixtures? What will happen if “touchless” buttons are applied? According to a lot of studies, viruses can contaminate commonly touched objects like elevator buttons and spread through entire office buildings, schools, hospitals and other busy facilities. Using public elevator with someone is a nightmare!”

Single button concept (Active state)

Single button concept (Active state)

Would I still have the idea if at that time I looked and smiled sweetly at her, or just say “sorry”? I don’t even know!

January 15, 2015

From that day, I always thought about her and also about this idea. After rendering the concept, I printed out, came along with a reminder letter and bouquet of roses to CGV Hung Vuong Plaza, hoping to meet her again to say “sorry for that touch” and “thank for the amazing idea”. This finding set off the insane pursuits of “a hidden treasure”, because I didn't remember her face nor her name. The only two things I know was that her hairstyle and she was shorter than me.

I kept my eye on the crowd and tried to remember how did she look like. 45 minutes hopeless waiting, I asked CGV staff who might know, it was very hard to know after the training period, she was moved to work at CGV Liberty Citypoint. :(

Another chance, I went to that place, searched around and then asked CGV employees once again for that girl. But they said they didn't know the girl as I described, they all gathered and clipped hair against their head at the crown, that kind of joke! It was, still is, my disappointing! In the end, I couldn't find out her. :((


Operational principle

flee-mo™ is a reflective type optical switch, diffused mode sensing (sometimes called proximity mode). Light from the transmitter (infrared LED), strikes the target (in the detection range), which reflect light arbitrary angles. Some of the reflected light returns to the receiver (sensor), and the target is detected.

flee-mo™ utilized a sensitive proximity sensor, so it only requires the approach of fingers, thumbs or any like-sized objects to initiate the choosing process. LED indicators that illuminate blue/red corresponding to Idle/Active state.

Which mean using this buttons without accumulate grime, bacteria and viruses in normal micro-stroke mechanical switches. With no moving parts, needs no maintenance, long life service and electrical isolation between input and control sides. It can be used as a stand-alone button for toilet flusher, touchless switch, etc. in which requires both hygienic and aesthetic.


Inspired by the modern art light from acrylic materials and colorful LEDs, the dramatic lighting pieces of button were made using LED acrylic, which was indirect illuminated using blue/red LEDs via light guide plate. It provides optimal light transmission while eliminating hotspots, for the purpose of creating something even more beautiful, toughness and elegance. Halo illuminations around the buttons meet the desired eye-catching effect and also decorate the attachment surfaces.

flee-mo™ on top of 10mm thickness texture acrylic plate  (shooting under bright-light conditions)

flee-mo™ on top of 10mm thickness texture acrylic plate
(shooting under bright-light conditions)

flee-mo™ on top of 8mm thickness ceramic tile  (shooting under low-light conditions)

flee-mo™ on top of 8mm thickness ceramic tile
(shooting under low-light conditions)



◉ Input voltage range: 100 - 240VAC
◉ Input frequency: 50/60Hz
◉ Input current*: 0.55mA @ 220VAC (typical)
◉ Input protection: T1A/250VAC (internal fuse)
◉ Power consumption*: Idle: 110mW || Active: 135mW @ 220VAC
◉ Load current: 1Amp max
◉ Inrush current: 12Amps (single cycle)
◉ Blocking voltage: up to 600 V
◉ Load type: incandescent/fluorescent/LED lamps, solenoid valves,...
Materials: acrylic, polyester film, polyolefin tube, plastic IR filter, polyamide glass-filled (3D printing), electronic parts & components
Installation: 8 - 12mm thickness tiles, 25 mm (1”) diameter cut-off

Common characteristics:
◉ Operating temperature: -25 to +70°C
◉ Storage temperature: -40 to +80°C
◉ Detection range: up to 50cm, adjusted to 0 - 10cm
◉ Turn-on time*: 0.14s (typical)
◉ LEDs: infrared, red, blue
◉ Operation: Idle || Active (Holding/Releasing mode)
◉ Electronic platform: built-in microcontroller
◉ Cables: 0.5 - 1.5mm² (22 - 14AWG) rigid/flexible/stranded
◉ Connections**: 4 x receptacle & pin pairs, 2 x expandable socket strips || 3mm slotted screw terminal block, 5 positions, top wire entry
Standard: (pending)
Degree of Protection: (pending)
Environmental compliance: Pb-free, RoHS compliant (pending)

(*) These specifications based on final prototype model, minor change may be applied.
(**) The interconnect between UI and insert is subjected to change to increase matting (insertion/extraction) force, avoid mis-alignment and waterproof.

Dimensions & Connections

The installation of flee-mo™ touchless switch only requires 25 mm (1”) diameter cut-off hole on wall tiles and ensures off-wall clearance bounding box.
Recommend circuit for use is “hot-line switching”. In this circuit, the hot side of the line is switched and the load maybe connected to either cold or neutral side.


#designwhatyoulove, #designtoimprovelife, #hygienic, #aesthetic, #touchless

(Click on each image to show the description)


flee-mo™ by Phuoc Nguyen (concept design & strategy), in collaboration with Nghiem Ngo and Toan Dang (electronics design). Photography by Lam Dinh.

Special thanks to Dr. Quynh Ngoc Do, Hung Viet Vu,Tri Hoang Nguyen, Sang Thai Pham, Hoa Tan Phan, Dan Hung Quoc Le, Hung Nhat Ho, Phuc Duc Dang.
Thanks are also extended to the representatives of Würth Elektronik GmbH & Co. KG (Germany), Silicon Laboratories (USA), TE Connectivity (USA), Littelfuse, Inc. (USA), Samtec (USA), Lucite International (UK) for kindly providing samples.