The post explains the making of a simple, cheap yet effective cell phone sanitizer circuit using ultra violet rays. The idea was requested by Mr. Shah (kristin).

Technical Specifications


Respected Sir,
I love your blog. I spend a lot time for searching circuit for countdown timer switch for 120v but I cannot find it. Can you please upload one or can guide me for the same?

I really need your help. Can you please able to give me circuit for countdown timer for 120V AC unit. I really tried in your blog to find one but I failed. Please Please give me circuit if you can.Thank you very much

I am making one UV sanitizer. I want to have countdown timer in that which can countdown from couple of seconds to minutes. I want to connect it to 120vac. Let say I want to place an iphone in that device for 3mins and 20 seconds for sanitization purpose after that time machines shuts off.
Shah



The Design


A cell phone sanitizer is a device which cleans or sanitizes (by disinfecting) a cell phone from all possible microbes, bacteria and germs that might be housing within the crevices present over a cell phone.

Since a cell phone normally travels with the owner across different places like inside transport vehicles, traffic jams, offices, railway stations etc. becomes prone to providing a cozy shelter for germs and parasites within

Making of the proposed cell phone sanitizer is actually very easy, it's more about fabricating the enclosure than electronics.

The UV bulb which is in fact a disinfecting UV bulb can be easily procured readymade or through online stores, you will find a wide range of these bulbs, the one which is reasonably small with the following specs can be picked.

The image of the UV bulb can be seen in the above picture.


Typical Bulb Specifications



  • Item Type:Ultraviolet Lamps

  • Voltage:85-265V

  • is_customized:Yes

  • Certification:CE,LVD,RoHS

  • Temperature:Warm White (2700-3500K)

  • Features:Germicidal

  • Average Life (hrs):1000

  • Warranty:1000 hours

  • Base Type:E17

  • Wattage:3W

Making the Cell phone sanitizer cabinet


It can be done with appropriately cut and dimesioned acrylic sheets. Basically a rectangular transparent or colored acrylic box able to hold two UV bulbs vertically and the cell phone in the middle needs to fabricated and joined as shown in the following image.

Two UV bulbs can be seen fixed over a small wooden box. If a countdown timer is used in the design, it can be housed inside this wooden box ans wired with the bulbs as indicated in the following counter down timer circuit.

If a manual switch ON/OFF is desired ten the timer circuit can be eliminated and the two bulbs wired in parallel directly with the mains cord.

The acrylic box should have a few projected pillars at the the bottom and on the walls such that the cell phone can be inserted between these pillars and stands erect.

The above position would facilitate an optimal exposure to the two UV bulbs residing within a couple of mm from the cell phone




The Countdown Timer Circuit


The optional countdown timer can be associated with the above UV cell phone sanitizer assembly for automatically switching OFF the bulbs after a set predetermined time.

The entire circuit description and the parts list can be studied in this article.

The two UV simply needs to be wired in parallel with each other, and in series with the triac as shown in the below given diagram.

Circuit Diagram


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