Reddit mentions of Pixel Wired Remote Shutter Release Control compatible with NIKON MC-DC2, for NIKON Nikon D7000 D5100 D5000 D3200 D3100 D90.

Here are some examples of a light painting experiment we did in my dining room http://imgur.com/a/vN4ko

I use a Canon but here's my "for dummies"/quickstart guide to light painting:

1. Set camera to M
   
   
2. Set exposure to the longest possible (on my camera it's 30 seconds)*
   
   
3. Set aperture. In the examples we used f/22. Experiment and see if you like the outcome. Now that I think about it. We had some problems with making that much light to show up. Something like f/8 would've been nicer to work with
   
   
4. Wear dark clothing, turn off all the lights
   
   
5. Hit the shutter then stand in front of the lens.
   
   
6. Paint! We used a cell phone with a flashlight app. Get creative. Sparklers, fire, LEDs, flashes, flash lights or anything that lights up can be used to paint
   
   
   
   TIP: if you're working alone, set the self timer to 2 seconds so that you have time to move in front of the lens before the exposure starts*
   
   *TIP: if you set the shutter speed to BULB then it will keep it open for as long as the shutter button is held down. Most remote-shutter releases have a LOCK or HOLD position that is very useful. You can buy a remote for under $10 on amazon. (You don't need to go name brand for this, it's just a button)
   
   TIP If you want to use BULB mode but down have a remote, you can
   "hack" it by using tape to keep the button down*

New with a DSLR, I'm going to buy a remote wired shutter release to help me with long exposure shots (startrails, etc), for my Nikon D7100

I see an inexpensive one for $7.50, is that good enough? Is there anything more I should be looking for? The one I'm looking at.

I find wired shutter releases like these much more reliable than IR. www.amazon.com/dp/B005TCJJ9M/ref=cm_sw_r_awd_VA5Xub0DX47BM


I have had nothing but problems with using IR remotes. With IR you will have to sometimes dance around while pressing it to get it to work. A wired or RF release will work MUCH more consistently