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  1. BobK

    RGB LED Control

    With a micro you can make them fade any way you want. Bob
  2. BobK

    Transmit and receive parallel data through radio link

    Well, then I would suggest the PT2262 and PT2272 which basically do what I said without using a micro. Only problem is that they can only do 6 bits of data. You could use 2 with different address bits to extend the number of bits and then alternate the transmitter between the two...
  3. BobK

    RGB LED Control

    You can control something to go through the spectrum with a single control. It can then adjust only hue, not brightness or saturation. If the control went from 0 to 3V, it could work like this: 0 = red >0 < 1 fade red to green 1 = green > 1 < 2 fade green to blue 2 = blue > 2 < 3 fade blue...
  4. BobK

    Transmit and receive parallel data through radio link

    If I were doing this, I would use a micro on each end and a protocol with enough redundancy that corrupted messages could be rejected. I.e. you transmit a multi-bit message that includes a code, the data and a checksum. Unless the code and checksum are correct, the data is rejected. The...
  5. BobK

    Voltage to current converter circuit

    For the third time, why not use an off the shelf audio power amplifier?????? Bob
  6. BobK

    My MCU circuit can't start by itself

    Are you using the high speed crystal (HS) config setting? This sounds like what it would do if you were using XT instead. Bob
  7. BobK

    bench power supply

    Are you basing the draw of the Peltier on it's specs or did you measure it? I have a little refrigerator based on one, and it blew out 2 power supplies because it was drawing way more than the spec. Bob
  8. BobK

    Looking at an arduino

    What is an "original" Arduino? I thought the platform was open-source, which means anyone can make it, and, assuming they did not change the design they would all be as "original" as any other. Bob
  9. BobK

    sensor to measure angular motion of hand

    Then a rotary encoder is the sensor you need. Bob
  10. BobK

    Voltage to current converter circuit

    Why are you not using an audio power amp? The OPA552 is limited to 200mA. Bob
  11. BobK

    Help with simple LED circuit

    You can run all 12 off two AA cells in series, by placing the LEDs in parallel. At 20mA each, that would be 240mA, the batteries would last several hours. You could run them at 10mA with a little loss of brightness and longer battery life. But, I would get super-bright LEDs and run them a...
  12. BobK

    measuring signals above 1MHz

    Then I would say that there is a problem with the triggering circuit in your scope. Bob
  13. BobK

    DIY VGA Controller

    People have done this with PICs. Search for "PIC VGA output". Bob
  14. BobK

    "Has it got the Cobalt?" (story)

    At the risk of self-aggrandizement and name-dropping, I would like to say a few words about Gordon Bell. He was one of a kind. Designer of the PDP-11, he became the senior vice president and chief technologist at Digital (#2 man in the corporation). I was hired by Digital to speed up the...
  15. BobK

    "Has it got the Cobalt?" (story)

    Actually, no, it was about the DG Eclipse! Data General was founded after there were two designs for the next generation (after the PDP-8) at Digital. One, designed by Gordon Bell was the PDP-11, the other was degined by Edson DeCasto who left Digital to found DG and it became the NOVA. Bob
  16. BobK

    "Has it got the Cobalt?" (story)

    You might notice that the instruction word is broken up into groups of 3 with the high bit a singleton. There is a good reason for that. The instructions are written in octal (base 8, digits 0-7). The instruction word was all based on 5 fields: 1-bit 0 for byte 1 for word operation 3 bits...
  17. BobK

    "Has it got the Cobalt?" (story)

    If you haven't manually entered the bootloader to a PDP-11 then you are not a real programmer. See the 16 switches. That is one instruction word, you flip them up for 1 down for zero, then you toggle another switch to load that instruction into memory and advance to the next address. The...
  18. BobK

    Transmit and receive parallel data through radio link

    What is it with you Brits. Here in the US, Mouser or Digikey have no minimum and the shipping charges are about $5. Don't you guys have illegal immigrants to process the orders cheaply? (At least I think that is why Mouser is located in El Paso.) Bob
  19. BobK

    Transmit and receive parallel data through radio link

    It is not clear to me what you are trying to do. If what you want is a xmit/rcvr pair that can encode 4 bits, i.e. have 4 channels that you can control on / off separately, there are such units available on Ebay really cheap with the encoder and decoder built in. Bob
  20. BobK

    "Has it got the Cobalt?" (story)

    Here is a sample COBOL program, to give you an idea. IDENTIFICATION DIVISION. PROGRAM-ID. Multiplier. AUTHOR. Michael Coughlan. * Example program using ACCEPT, DISPLAY and MULTIPLY to * get two single digit numbers from the user and multiply them together DATA DIVISION. WORKING-STORAGE...
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