Quote:
Originally Posted by ishiyakazuo
I didn't look at the LCD power ratings, but do backlights use that much still? I guess 1.5W isn't that bad when hooked up to a car battery, but I'm a little surprised -- I just wrapped a project a few months back with an ARM7 @ 48MHz with USB, an FPGA and a 2x16 LCD (non-backlit) and the entire setup amounted to about 1W off of a +5v supply.
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Pretty close, depending on size and backlight. I have a box of white-lit 4x20 here that draw up to 320mA at 3.4V. That's a 1.6W at 5V, and we provide a 0.5W heating element. If you don't like the heat or the 1/2W R, you can always PWM them over a TIP120 with 10k to base at max 60% duty-cycle (which is an analogWrite ~160). The 10k limits IB to 0.5mA, which the darlington multiplies by 1,000 to 500mA Ic. LEDs tend to be pretty proportional in their relationship between duty-cycle and I. Good idea to reduce Arduino's PWM scaler tho, as the 400Hz default still does 15ms...
ok, but I'm rambling.