Multi-Color Light Painter (Touch Sensitive)

Light painting is a photographic technique used to create special effects at slow shutter speeds. A flashlight is usually used to "paint" the images. In this Instructable, I will show you how to build an all in one light painter with touch switches. The touch switches are quite simple to make.

Touch Switch

• Prototyping board
• Enclosure (e.g. pen case)
• Lead-free solder
• 1 x 9V battery
• 1 x 9V battery clip
• 5 x 2N7000 N-channel MOSFET
• 5 x 10M resistors
• Heat shrink tubing
• Wires

Multicolour lights

• 4 x 5mm red LEDs
• 4 x 5mm yellow LEDs
• 2 x 5mm green LEDs
• 2 x 5mm blue LEDs
• 2 x 5mm white LEDs
• 2 x 20-ohm resistors
• 3 x 82-ohm resistors
• Quick setting epoxy

Tools

• Soldering iron
• Hot glue gun
• Drill

Drill holes for the LEDs and wires to fit.

The touch switch here is a momentary switch that uses N-channel MOSFETs. When you touch +9V and gate, the LEDs turn on. The MOSFET requires up to 3 volts to turn on. Compared to mechanical switches, touch-sensitive switches respond instantaneously and allow you to use multiple colours at the same time. In this circuit, there are six wires, which are the electrodes. The 10M resistors allow the MOSFETs to turn off when you release the switches.

Update: 20-ohm resistors are suitable for red and yellow LEDs. 82-ohm resistors can are suitable for green, blue, and white LEDs.

Attach LEDs using epoxy. Allow them to set before soldering.

To make the switches, strip the wires and coat it with lead-free solder. Solder the wires to the gate of each MOSFET. Hot glue the wires to the case. If the case is conductive, you may use hot glue to insulate it from the wires.

Tip: If you have scarp solder, this is where you can use it.

To light paint, set the shutter speed to long exposure and use a timer. Mount your camera onto a tripod. I used 10 seconds of exposure for the photos shown here). The longer the setting, the more time you get to light paint. You can also use an RGB LED to produce other colours.