Welcome, Guest
Username: Password: Secret Key Remember me

TOPIC: 44 LED Light Wand From Surplus Gizmos

44 LED Light Wand From Surplus Gizmos 3 years 4 months ago #17636

  • Jon Chandler
  • Jon Chandler's Avatar
  • Offline
  • Moderator
  • Posts: 365
  • Thanks received: 352
Surplus Gizmos in Portland, OR has some nifty yellow LED light wands for $3 a piece. These are about 30" long with 44 LEDs in a metal channel with a threaded fitting on the end. The LEDs are individually controllable (on/off) using shift-register-based LED driver chips, so they'll be easy to control using Swordfish or whatever. My partner picked up some of these for me while in was in Portland this weekend.

Seems like there are a lot of possibilities for these strips. How about a 60" POV display? Mount 2 strips on a hub for balance and display something awesome. Just don't get in the way - with the metal channel, getting smacked by one of these rotating at any speed with not be a good thing. Hazard lights for your car? An illuminated bargraph for your charity fund raiser? The theater marque you've always wanted? For three bucks, there seem to be many possibilities!

It appears the ST Mirco chip is obsolete, but there's a data sheet available here. Interfacing should be the same as for a '595 shift register.
  1. Set /OE high
  2. Shift out 48 bits corresponding to the desired state of each LED
  3. Cycle /LE to latch the data
  4. Set /OE low to display the pattern
  5. Delay a while and repeat

The above procedure is to display a completely new pattern. A moving pattern may be displayed by shifting a bit, then latching and displaying the output to move it one step at a time.

Why 48 bits you may wonder? There are only 44 LEDs on the wand. Each chip supports 8 LEDs, with 4 bits of one chip not being used. You have to shift 48 bits to "flush out" those extra bits.

There's a '595 shift register simulator here (which doesn't seem to work in Chrome) that helps to explain the concept.


The following user(s) said Thank You: hop

44 LED Light Wand From Surplus Gizmos 3 years 4 months ago #17637

  • Jon Chandler
  • Jon Chandler's Avatar
  • Offline
  • Moderator
  • Posts: 365
  • Thanks received: 352
No difficulty at all getting this thing to come to life. I wrote some code for a shift-register-based bargraph from Sure Electronics years ago, and it just took a few slight mods to bring this to life. The biggest change was the output enable is high on the Sure, low on this unit. And changing the number of LEDs from 40 to 44.

44 LED Light Wand From Surplus Gizmos 3 years 4 months ago #17640

  • hop
  • hop's Avatar
  • Offline
  • Platinum Boarder
  • Posts: 526
  • Thanks received: 46
Pretty neat, and a lot cheaper than my 8 channel light rod. A lot more nimble too. :)
Time to create page: 0.234 seconds