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  1. BobK

    Slim Motor for electric Fan

    Pancake motors. Size and power are a tradeoff. You can probably find a strong one in the size you want, but it won't be cheap. Bob
  2. BobK

    DAC and ADC Simutaneous Testing

    Harald, it is you your precise German interpretation of simultaneous. I am of half German descent, so I know. :) Bob
  3. BobK

    Modify AM radio receiver to pick up radar-like ping?

    What kind of receiver does the manufacturer recommend? Surely they must say something about the receiver, or possibly even sell one. Bob
  4. BobK

    Transmit and receive parallel data through radio link

    Kris's circuit looked pretty complete to me. I eagerly await his explanation. Bob
  5. BobK

    RCA (composite video) to LVDS converter design

    From Wikipedia: So the camera is sending a stream of bits to the screen. This is way different than composite video. To convert composite video to this format you would have to have a very complex converter. Unless such a thing exists already, making it would not be an easy project, nothing...
  6. BobK

    Light measurement

    Hmm, I thought I saw that and now I cannot find it. Another data sheet said 5V to 40V for the power. I guess I was wrong. I cannot imagine it would be very useful at 5V, seeing as the outputs cannot get close to V- or V+ They are always characterized only at + and - 15V, so anything goes at...
  7. BobK

    Transmit and receive parallel data through radio link

    Okay, that is not what is shown on your diagram. So the scan signal acts as a start bit. That could possibly work, but the receiver should wait 1/2 a clock before latching the first data bit. Bob
  8. BobK

    DIY Speakerbox

    Much better to use the voltage of battery that you need. A boost converter would just waste power. I would use 8 D cells to run this. At 20W they should last about 6 Hours. Bob
  9. BobK

    Boost converter current calculation

    Damn, I just looked it up in Digikey and they only sell in QTY 1000. Bob
  10. BobK

    DAC and ADC Simutaneous Testing

    I think you are probably asking a simpler question than Harald is answering. Do you mean that you don't know how to program the writing to the DAC and reading from the ADC as opposed to only being able to do one of those two things? If so, here is how. Assuming that the ADC can operate at...
  11. BobK

    DIY Speakerbox

    Do be aware that the power you can get out of this depends on your battery voltage. Use 12V if you want to get anywhere near 20W. I calculate that the max you can get from 12V is 18W. At 6V this would go down to 4.5W. Both are into a 4 Ohm speaker. For 8 Ohm speakers reduce by a factor of...
  12. BobK

    Boost converter current calculation

    For the same chemistry, the same weight of battery will provide roughly the same amount of power no matter what the voltage is. So adding a boost converter (which, in this case would be heavy because of the massive inductor you would need), does not help at all. Use a 12V battery. Bob
  13. BobK

    Light measurement

    A 741 is specified for a minimum of + and - 9V. And the extent of the outputs can be as bad as 3V from V+ and V-. So, with a 9V single sided supply, you can only expect the output to swing is from 3 to 6V. I agree with Kris, either a 358 with +7v or more or a rail-to-rail opamp. I would go...
  14. BobK

    Arduino programming...for absolute NOOBZ

    There have to be plenty of Arduino tutorials out there, but I am not going to google it for you. Bob
  15. BobK

    Strange voltage reading from AC adapter

    Given that you have a 50 year old voltmeter, I would not trust it's readings. It is possible the AC input has no capacitor (or a shorted one) to block DC and that is why you get a reading on AC. With the adapter reading near the correct voltage, I would suspect the battery. Bob
  16. BobK

    Transmit and receive parallel data through radio link

    If you know C++ you also know C. C is a subset, you just have to know which parts of C++ are not included. Bob
  17. BobK

    Transmit and receive parallel data through radio link

    I don't know why you think the clocks at the transmitter and receiver would be in sync. Please explain. The protocol I describe is called asynchronous serial for a reason. I cannot follow at all the table you have posted. Please just tell me what you would expect the xmit data to be...
  18. BobK

    How Transistors Work

    If B is a function of A and A is the cause of something, one can pretend that B is the cause and you will not get any incorrect result. So it really doesn't matter. The only question is which is easier to use in practice, the relation of Ib to Ic or the relation of Vbe to Ic. Bob
  19. BobK

    Arc of LED lights...any ideas?

    Well, even if it is always on, you will still have to load up the data for each LED, assuming you use the NeoPixels. Bob
  20. BobK

    Arc of LED lights...any ideas?

    Yeah, that's what some of us were already talking about. ;) Bob
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