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Member Since: May 28, 2011

Country: United States

  • The SX1509 goes up to 400kHz I2C rate, so you'll be more limited by the I2C bus than your MCU clock. Even though it's only 400kHz, the I2C read/write operations are quite small (Think 3-4 bytes typically). Theoretically, you should be able to do an operation every 0.1ms or less as long as conditions are good (and as long as the SX1509 can keep up - I've noticed that some operations cause a small [~1ms] delay). That said, this module also has some very useful features that let you set a PWM, Blink, or Fade effect so if you for instance need to flash an LED at 5Hz you could start it with a couple of setup commands and and stop it with another. This minimizes the total number of I2C operations required for a lot of common tasks. I have used a couple of SX1509s (with an RPi master) to control a multi-zone heating and humidification system for a reptile habitat - it worked out quite well for PWM control of the fans and heating elements.

  • Seems like a Gumstix Overo Air or similar module and compatible expansion board would be about perfect if it's within your budget. I've used them as APs with the Tobi expansion board in automation projects previously, and I'm sure they'd perform quite well in a robotics environment. It doesn't exactly sip power (~4w consumption while driving a monitor and on wireless), but would be much more efficient than an ITX system and does have some nice power saving capabilities that I have not needed to explore.

No public wish lists :(