Thread: Can Relay Outputs Directly Drive LEDS ? (for testing)
View Single Post
  #1   Spotlight this post!  
Unread 15-03-2008, 16:00
de_ de_ is offline
Registered User
AKA: Dave Edwards
FRC #1310 (Runnymede Robotics)
Team Role: Mentor
  
Join Date: Apr 2005
Rookie Year: 2005
Location: Toronto, Ontario
Posts: 256
de_ is a jewel in the roughde_ is a jewel in the roughde_ is a jewel in the roughde_ is a jewel in the rough
Can Relay Outputs Directly Drive LEDS ? (for testing)
All 8 relay ports are in use this year (that's a lot of Spikes & PWM cables !). We like to test our software out first on a table test board as much as possible. We would prefer to not have to dedicate 8 more spikes and pwms just to have visual confirmation of the state of the relay outputs.

If I read Kevin Watsons CPU to RC I/O mapping chart and the CPU spec also posted by KW, it appears each pin might be able to provide 25ma, enough to power a led (with an appropriate dropping resistor). We would probably limit it to 10-15ma (just enough to see reliably).

Anyone one know for certain this is doable or more importantly if its a bad idea ? I would hate to blow our test RC. (We asked Innovation First but did not hear back.)