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JRad

Member Since: January 13, 2011

Country: New Zealand

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University of Canterbury

  • This can work directly on 240V!! (try at your own risk, and ONLY attempt this if you’re experienced)

    I reverse engineered the circuit, and found that most of the components should be able to handle 240V. Here’s the mains side of the circuit:

    Schematic

    The modifications required are circled in red. Basically all you need to do is swap out the transformer!

    First I carefully measured the circuit on 240V using a 100W incandescent light bulb to limit the current. All the voltages checked out, and nothing got hot or burnt. I then removed the light bulb, and checked that the station operated correctly.

    The heater element heats up extremely quickly, but since it’s temperature controlled, the higher voltage doesn’t seem to matter. However you must make sure the pump air speed isn’t turned above half power. There is a trimmer pot that sets the minimum airflow, so that needs to be turned down.

    Proof it works:

    Photo 1

    Photo 2

    Please remember mains voltage is lethal! Try this at your own risk, and be aware doing this could burn down your house, etc etc. Also since the circuit wasn’t designed for 240V, there’s no guarantee it won’t blow up eventually

  • Not a stupid question at all since I can’t see it anywhere either. I have a similar LED strip and it’s common Anode (+12V). Common anode is easier to drive, since you just ground the R,G,B pins with a MOSFET to turn each colour on.

  • Flickering is due to the PWM driver, not the LEDs. You need to increase the PWM frequency to remove flicker.

    1. the tablet has the special charger built in, so yes you can swap the batteries

    2. Yes 850mAh is the capacity. It’s fine to attach a higher/lower capacity battery (though the tablet may not be calibrated to it and may possibly show different battery levels)

  • and a built in isolating transformer for ethernet

  • I’m sorry New Zealand!

    That’s ok, I managed an all-nighter for the last one, I can do it again!

  • That’s fine if you want DAC for your chip, but this chip is great if you actually want a variable resistance: eg. Adjustable low-pass filter. Also, PWM introduces lots of noise.
    however, note that the pins in this chip cannot go below 0V or above VDD, which makes them a bit useless in audio when you need at least + and - VDD. This is very important, and it tripped me up when using a similar chip.

No public wish lists :(