Multi-Color Light Painter (Touch Sensitive)

Intro: 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.

STEP 1: Materials and Tools

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

STEP 2: Drill Holes on the Case

Drill holes for the LEDs and wires to fit.

STEP 3: Touch Switch

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.

STEP 4: Attach LEDs to the Case

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

STEP 5: Solder the LEDs

STEP 6: Electrodes for the Switch

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.

STEP 7: Mount the PCB

STEP 8: Light Paint

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.

Comments

[kostya]

Nice and simple project. Thanks for sharing! I think you can build 4 touch switches around one 4001 CMOS chip.The circuitry will probably draw less current and the battery will live longer.

[hanlin_y]

To get those values, you can add resistors in parallel or series but their values do not need to be precise. That's what I did. Here's a calculator for parallel resistors. http://www.1728.org/resistrs.htm

[kostya]

Thank you. I'll try to use your shematic idea in my micro LED flashlight on a super capacitor. These MOSFETs (2N7000) are dirty cheap here. As touch pads I'm going to use snap buttons. Those nickel-covered ones are easily soldered.

[kostya]

Thanks for the reply.The only problem is that 4001 gates can produce just a few mA, so the LEDs won't be half so bright as in your project. It can be cured by adding NPN transistors but the game is not worth candles, assuming cost and complexity. I was wondering where you managed to get those resistors of 20,40,60 and 80 Ohm. Here in Ukraine they are considered non-standard. The closest standard ones are 18,36,62 and 82 Ohm.

[hanlin_y]

You mean less current with the LEDs off? From the data sheets, both have similar standby current but the chip may be great for smaller PCB's. Thanks for the suggestion.

[kubaa434]

It looks amazing :)

[jessyratfink]

Love the last step - the colors look great!

[ncoleman2]

Good job, this looks really cool! I want to try this sometime...