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  1. dorke

    Voltage when using USB Splitter

    What you have is a Y-cable not a proper USB-splitter. In that Y-cable powering from the 2 males will cause a +5v conflict,don't use it. Why not power the Arduino from the laptop using a standard USB cable( both power and doanload) ?
  2. dorke

    What resistors should I use to reduce power from 120v outlet

    Please a clear explanation would help. Can you put a diagram of what you did and why?
  3. dorke

    parallel led array

    lightman, These DC-DC down converters are fine(based on the LM2596 Ic etc). But, You will never get to a very good efficiency(over 90%) with a low output voltage of 5V and under. depending on the actual output voltage you work with you should expect something in the range of 65-75% efficiency...
  4. dorke

    Sound activated switch advice

    Yes,just to get more output current. For driving a MOSFET one inverter is enough. In this circuit the LED is "on" when the output is "0" If you need a "1" to drive the MOSFET "on", use one of the 3 inverters you "freed" to invert the current output .
  5. dorke

    Sound activated switch advice

    O.K here it is an "all digital " amp and circuit. The circuit is based on a single un-buffered hex inverter IC CD4069. It's drive capability is limited. If more drive is needed the 74HCU04 can be used,in this case use only 4 AA batterys to work it with 4.8V to 4.1V The AMP uses the linear...
  6. dorke

    Diodes Circuit analysis

    Look at the attached pic: looking at point X (=Vo) : you need to ask, at what voltage at point X does D1 actually conducts? The answer is: 1v +1ma*1kohm+0.7=2.7 v if X is at 2.7v what is the state of D2 and D3 ? The answer is they are cut-off(not conducting). Now you ask what is the voltage...
  7. dorke

    Is USART interrupts, error correction, & address detection necessary for my project?

    I didn't read your code,but will answer generally: ==>"interrupts" First thing to ask is: other than what you described( PIC1=reading switches states and sending.PIC2=receiving states and driving LEDs ), are the PICs doing anything else? If they don't do anything else, the "polling" of PIC2 is...
  8. dorke

    A stepper motor, I2C bus and a Raspberry Pi

    well, Good news,this scenario was found than: "===> Also, you can try to run your code on another Raspberry Pi(yours may be defective "I/Owise") with your own TMC222." That means the I2C interface on it is faulty h/w wise. If you are interested for educational purpose , it can be traced and...
  9. dorke

    parallel led array

    Here is another very simple idea for you to try: Use 1 Battery to drive directly(no resistor!) 3 X IR LEDs in series. This way you get no losses at all. The maximum voltage you can get from a fully charged Li-On battery is 4.2Volts Each LED will get a maximum of 4.2/3= 1.4Volts. So it is...
  10. dorke

    Allan Timer Circuit

    Indeed it is. Time and timing is a fascinating area. Here is another for you: attoSec record , not quite in the realm of us White Rabbits dealing with switching mechanical relays ...o_O
  11. dorke

    Hacking a microwave oven

    Al, Cooking wise,(all? )chefs never use a Microwave oven for cooking, If it all, they use it to warm things and perhaps defrost. I'm sure you can find plenty of regular "smart ovens" to do what you need. For your own good, You should never even think about opening the lid of the Micro !:eek...
  12. dorke

    I am pretty sure my answer is right!!

    Dave, You both got it wrong... The density of copper is indeed 8900Kg/m^3 not gr. A 1x1x1 meter cube of copper weighs about 9tons not 9Kg...;) The problem is in transferring the wire diameter from mm^2 to m^2 the factor should be 1x 10^-6 and not 1x10^-3...;)
  13. dorke

    I am pretty sure my answer is right!!

    "I see that I get my answer in grams, why is that? Please,show your calculation and we shall find out why.
  14. dorke

    parallel led array

    ligtman, BobK is absolutely correct: The way to drive a power LED(s) is with constant current. It will be the most efficient way and will yield longer possible battery time. It is more complicated to implement and involves constant current high frequency dc-dc converters. such as the LM3410...
  15. dorke

    A stepper motor, I2C bus and a Raspberry Pi

    "1. The Raspberry Pi can run other segments of arbitrary code and shows no change aside from the "I/O Error" we keep getting with the motorcode." ===> Isn't it the easiest thing for you to find what generates the "I/O Error" message in the Raspberry Pi code itself? "5. We tried to make the...
  16. dorke

    Allan Timer Circuit

    Here is the data sheet of the uC sm8952AC25PP "soft copy"? - the IC has "Code protection function". If enabled you won't be able to do that...
  17. dorke

    Allan Timer Circuit

    I doubt this is the one you are looking for but here it is: DMTD
  18. dorke

    Missing parallel resistors

    Hop, Your are full of surprises... RPN, as in Reverse Polish Notation... another Joke the Poles played on us.:p That "joke" became quit a nightmare when I had to write recursive functions using RPN in C and Assembly back in the 80's. I almost got stuck on a stack with it,for many hours... :(...
  19. dorke

    parallel led array

    Yes, the SMD diodes are easy to solder ,not a problem at all.
  20. dorke

    parallel led array

    Don't listen to Colin's B.S. Definitely use the diodes!!!
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