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  • Grumpy Mike commented on AndreasN29's instructable RFID Lockbox6 days ago
    RFID Lockbox

    That is just the power but you are feeding the 5V SPI signals from the Arduino into a 3V3 system. Do you not understand the consiquences of this?

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  • Grumpy Mike commented on AndreasN29's instructable RFID Lockbox1 week ago
    RFID Lockbox

    I can't see any level translators between the 5V Arduino system and the 3V3 RFID board. While this might work initially it will, in time, fry your RFID card.

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  • Grumpy Mike commented on calmac_projects's instructable Arduino Powered Headdress1 week ago
    Arduino Powered Headdress

    Great idea but sadly very poor electronics design. Why two processors when one would have done? Why have all the strips driven off the same pin, this reduces flexibility. The omission of the resistor and capacitor means you project will fail much sooner than it otherwise would.

    See https://forum.arduino.cc/index.php?topic=514957.0 for why.

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  • Grumpy Mike commented on noahw's instructable LEDs for Beginners2 weeks ago
    LEDs for Beginners

    You said at the start:- "Never done any work before with LEDs and don't know how to use them? Its ok, neither have I."So what makes you think it is OK to perpetuate the rubbish ideas here.You always need resistors with LEDs, period, no ifs & buts.If you try and wire LEDs in parallel without a resistor they will not share the current evenly and you will damage them.

    You said at the start:- "Never done any work before with LEDs and don't know how to use them? Its ok, neither have I."So what makes you think it is OK to perpetuate the myths you have here?You always need a way to control the current with LEDs, and the simplest way is a resistor. The no resistor circuits shown here uses the internal impedance of your battery to limit the current, if you use another type of battery you can start a fire or have an exploding LED. It is irresponsible of you not to point this out as it could be a danger.If you try and wire LEDs in parallel without a resistor for each LED, they will not share the current evenly and you will damage them. Look at your own picture and you can see they are not the same brightness.

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  • Grumpy Mike commented on Karlstrom's instructable Build Your Own Microcontroller9 months ago
    Build Your Own Microcontroller

    Why are the decoupling capacitors not ceramic? The ones you used are not very effective.

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  • Building a Keg Still (Bokakob Design, Reflux Still)

    "in the UK you can have a still that makes up to 5L if you have a permit.":Well that is a way oversimplification. See the second post in this link:-http://ww.homedistiller.org/forum/viewtopic.php?f=...

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