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Recent content by prototypingfool

  1. prototypingfool

    receiving serial data on 8051 and writing to multiple ports

    New to C programming and the 8051 and I'm trying to modify a program to receive 3 bytes of data, and write those bytes to Ports 0,1,2. I'm hoping my input would be something like 000000001111111100000000 and Port 0 would show the first byte, Port 1 the second, and port 2 the last byte. I'm using...
  2. prototypingfool

    Blocking/Bypass Diodes in Battery Circuit Help//

    -Batteries are not getting charged. Plan is to install them till they run out of juice, or run off of the VCC port when something is plugged in... Just found this on a google search as well http://www.discovercircuits.com/H-Corner/bat-iso.htm -is too complicated? Would love to just use simple...
  3. prototypingfool

    Blocking/Bypass Diodes in Battery Circuit Help//

    In the attached schematic i'm trying confirm my blocking diodes are located in the right position, and if i need resistors as well. Design goal is to put a circuit in (using diodes) that will assure the batteries dont charge each other AND if one battery goes bad, the entire system wont shut...
  4. prototypingfool

    Digital Accelerometer + GPS chipset questions

    I'm wondering if anyone heard of a combo chipset that has a GPS receiver and a 2 or 3 axis accelerometer within the same package? Any help or direction would be appreciated! I know i can combine two individual chip sets but wondering if anyone has made this work with each other. Thx,
  5. prototypingfool

    Is there a Voltage regulator with high/low (on/off) pin?

    Benta, thanks very much for your straight forward answer. Wish everyone was as helpful. cheers!
  6. prototypingfool

    Is there a Voltage regulator with high/low (on/off) pin?

    thanks, sure a diode can do that would rather find a neat voltage regulator that does it similar to a diode. Or what i meant was can anyone suggest a good diode circuit that can do it. Thanks for your help
  7. prototypingfool

    Is there a Voltage regulator with high/low (on/off) pin?

    I'm whipping up a circuit that uses +15V via a standard Voltage regulator. I'd like to have the regulator shut off, or turn off, when a transient voltage is applied. i.e. a separate DC voltage is introduced into my circuit and i want to use that to shut off the regulator. Can a diode do this...
  8. prototypingfool

    Measuring gain in dBi with VNA - s21

    I've measured my prototype antenna using a known Reference Log Periodic. Test set up was the known Log pointing at my prototype Antenna Under Test (AUT) using S21 on my VNA.Cable length was calibrated out. How do i determine the AUT's gain in dB or dBi? I thought, i took the LogMag measured...
  9. prototypingfool

    3D PCB

    Is there a service that could make a Printed Circuit board in 3 dimensions? Testing a concept. Can get flexible PCB and put on a fiberglass structure, but would prefer the PCB itself shaped. thx,
  10. prototypingfool

    4-6 GHz Balun design?

    Also, i'll need it up to about 5 watts, so a reference design i can etch would be ideal. f
  11. prototypingfool

    4-6 GHz Balun design?

    I meant loop antenna (sorry) and why would a 180degree hybrid do the job? Yes, etching. F
  12. prototypingfool

    4-6 GHz Balun design?

    I'm prototyping a small dipole antenna from 4-6GHz and am looking for a good reference design for something in that frequency range. There are a number of chip baluns available but have a higher insertion loss. I'm etching the antenna on standard FR-4 pcb. I'm hoping there is a "balun...
  13. prototypingfool

    transmit/receive switch help

    thanks, not transmitting to gps. ;) Was a hypothetical again, thanks!. Any way to private message here? f
  14. prototypingfool

    transmit/receive switch help

    VB, I have a single puck antenna with two ports (prototype). Isolation between both pins are terrible (-5dB) as expected. I'd like to protect the LNA when in transmit mode. They never operate simultaneously. Catch is i only have DC when LNA is on. Some thoughts i have is: When LNA is off, and...
  15. prototypingfool

    transmit/receive switch help

    Understand..thx, but trying to find a switch with one voltage line (and no control) is the problem. Appreciate the help. f

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