Automatic bathroom night light using a Digital Skeletal LED Clock and a IRF520 MOSFET Driver module

This simple project uses a standard Digital Skeletal Clock to gently illuminate your bathroom at night without having to turn on the main lights.

The clock is normally off and will illuminate once the bathroom door is shut or if the optional PIR detector is used as soon as you enter the room.

Updated schematic uploaded with correction to IRF520 connection-5v added direct to SIG input.

Step 1:

Parts List

Digital Clock module Ebay

There are several types available, search for 3D digital wall clock. White LED is best for a night light. Make sure it does not have an auto night dimming function as the clock needs to be bright to light your room.

Some have an manual adjustable brightness setting which is probably a nice feature to have.

IRF50 Module Ebay

This is an electronic switch and just turns the power to the clock on and off when it receives a high signal from the door contact or PIR.

Magnetic Door Contact Set (optional)

This is a simple magnetically operated reed switch as used in burglar alarm systems. Sold as flush fit- fitted flush to the door and frame for a neat appearance or surface mount not so neat but quick easy to instal.

PIR (optional)

These cheap modules are available on Ebay and sense the heat from your body when you enter the room. They have a variable switch off delay.

Mounting Plate (for PIR option)

Standard blanking plate as used on mains sockets available in many finishes.

Mounting Box (for PIR option)

Depending on your wall you will require a plasterboard (drywall) box or for a masonry wall a metal flush mounting box.

Switch

Master switch disables the night light by removing power from the whole circuit.

Power Supply

You will need a regulated 5v power supply. Current capacity will vary depending on your clock module but 1amp should be fine. Depending on local regulations you probably won't have a socket in your bathroom so the power supply will need to be plugged in another room.

I fitted my night light clock while I was fitting out the bathroom so had no problems hiding the wires.

Step 2: 3D Digital Clock Module

The White LED Clock module runs off a 5 volt supply and is triggered by a sensor in the door via a IRF520 MOSFET Driver module.

The clock has built in battery backup for the time and is set by 3 buttons on top and has 12 or 24 hour display.

Some clocks allow you to manually adjust the brightness of the display. Availability of different types of clock will vary as the manufacturers changes the features so check the description carefully before you buy.

I have not tried them but one to avoid is the clock with an automatic night dimming function as these may not provide enough light to illuminate your bathroom when it is dark.

The clock I have used measures 21.5cm x 7.5cm but there are larger alternatives available.

Step 3: IRF50 Module

An IRF50 MOSFET Switch Module is used to switch the clock on and off. The input of the module is connected to a reed contact in the door frame or can optionally be controlled via a PIR module.

Step 4: Magnetic Door Sensor

This is a simple magnetically operated reed switch as used in burglar alarm systems. Sold as flush fit, fitted flush to the door and frame for a neat appearance or surface mount not so neat but quick easy to install.

Make sure that the contact type is open when the door is open and closed when the door is closed.

Step 5: PIR

These cheap modules are available on Ebay and sense the heat from your body when you enter the room. They have a variable switch off delay.

Connect it to you 5v supply and the output to the "SIG" input of the IRF50 module.

The PIR Module is fitted into a standard blanking plate as used on mains sockets and is available in many finishes.

The IRF 50 is fitted into the mounting box for the flush panel.

A Master On Off switch is also fitted on the flush panel.

For construction details on fitting the PIR and switch into the flush panel see my web site here .

Step 6: Schematic With Door Contacts

Wiring is very simple with connections from the IRF50 module to the 5v power supply the clock power in and the door sensor.

The IRF 50 is fitted into the mounting box for the flush panel.
A Master On Off switch is also fitted on the flush panel.

Step 7: Schematic With PIR Module

Wiring is again very simple with connections from the IRF50 module to the 5v power supply the clock power in. Power also goes to the PIR sensor along with a single wire from the output of the PIR to the IRF50 module.

The IRF 50 is fitted into the mounting box for the flush panel.
A Master On Off switch is also fitted on the flush panel.