Shop OBEX P1 Docs P2 Docs Learn Events
WAM - Digital Display? — Parallax Forums

WAM - Digital Display?

mj37mj37 Posts: 6
edited 2006-04-16 05:12 in Learn with BlocklyProp
1) Why 1 Kohm for each LED is used in chapter 6? Why not 470 ohm for each LED as in earlier chapter?

2) Are there any sample code·for·boe-bot navigation and the use of·gripper add-on?

Thanks

mj

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-04-16 05:12
    mj,

    ·· The reasons are that you cannot draw more than 50 mA per group of 8 I/O pins.· With 470 ohm resistors when all segments were lit it would be too much current.· 1K resistors limit the current even further preventing this from happening with so many LEDs being lit at once.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
Sign In or Register to comment.