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Posts posted by GreekPIC

  1. 1.in the below pic is that 5v regulator only?

    There's a 7805 5V controller onboard. It can take 8-35V as an input (actually whatever voltage the steppers need) and output 5V for the UCN chips

    2.how to connect home limit switches?
      if we use 3 limit switches for home then overall we need 6 switches. right?

    Depending on the software you use, you can use NC or that as the switch being pressed and it will stop. You can spare some parallel port pins by wiring all three limit switches in series. The limit switches are no to be used on purpose like the home switches so you can live with that. If the machine hits a limit, you can visually check which axis it was.

    3.i have some 5-6 wire stepper motors from old printers.how to know whats their  voltage rating.imean 12v or 24v etc

    Now, that's hard. Google each and every marking, serial number or brandname you see on them and try to find a datasheet.


  2. and who program is best for you?

    Like I said, in my opinion EMC2. TurboCNC is easy to setup and runs on old PCs but is rather limited in capabilities. I didn't get into much detail with Mach, but EMC2 seems very impressive. It even has ladder programming (language used in PLCs).

    what caind of step motors do u use?

    Small inkjet printer motors. This is a small, proof of concept machine. I've bought bigger, used motors for a bigger mill or a retrofit.

  3. [were i connect 5V???????

    Nowhere. It's created on the board. Look at the PCB. It's my revised version but the basics are the same:


    The 12v is connected to the two large pads on the right. The three pads next to them to the left are for the 7805. The lowest (square) is 12v input, the middle is GND and the topmost is the 5v output, which feeds the ICs

    The large trace going up and then left, carries the 12v to the motors.


  4. this board use +5v power suply

    It doesn't. It has an on-board 5v power supply circuit with the 7805 regulator. It takes a 8-24v input.
    but i have some step motors whit 5 wires who works on 12 V

    You connect 12v to the board. It goes straight to the motors. It also goes through the 7805 to provide 5v for the chips.


  5. You won't be able to supply 12 volts to the stepper in this configuration. Just connect to the board. In a configuration where you use 12 volts for the stepper, you usually use a different stepper.  Aren't your steppers 5 volt ones? I thought this was the case. In a setup where you would use both the 5 volt and the 12 volt tap of the power supply, you would have your digital circuitry running from the 5 volt source and the motor circuit running from the 12 volt source.


    MP, his main problem is that he has a bipolar motor while the board only supports unipolar ones (5,6,8 wire motrors).

    There is a circuit that can be added to the board to drive bipolar motors (I have it around somewhere) but it needs 12 power transistors per motor. It's much better to just look for another motor.


  6. hello, i'm making my own CNC mill and i was wondering where the schematics for the  UCN5804B motor controller. i saw the schematics but there a litttle scetchy and i was wondering if anyone has pictures of there pc board layout. and i just saw a picture posted on this forum of the bottom of a pc board where he drew i the limit and home switches and i wonder where he got that. thanks ahead

    On the project page you'll find the schematic, pcb layout and parts overlay in *.ps format.

    Here is my modification, I changed it a bit to suit my needs.


  7. Here is a pic of a power transistor (shiny silver color) bolted to a cast aluminum heatsink (black with many fins for high surface area) with a mica insulator between (white color).
    This is from the power supply in our Projects Section.

    Audioguru, heatsinks are actually extrusions, not casts. I've seen a cast heatsink from an old Russian (or should I say Soviet) appliance and it was UGLY!

  8. I'm looking for 17 TFT VGA 640x480 contollers. All I can find online is contollers that can do 640x480 but go up to 1024x768 so they are expensive.

    I've bought two Digital View ones from ebay for ~45$ over a span of a year but don't want to wait 17 more years for the rest  :P .

    Doesn anybody know a source for such hardware? New old stock or even good condition used ones could do.


  9. Ok, small update. I found the PWR SW connection. Shorting pins 1 & 2 powers the system up and holding them for ~10sec turns it off.

    However it doesn't boot up. So I still need help for the manual (or ideas on what might be wrong). There is a DIP switch on the M/B I can't figure out and I'm not even sure it supports the CPU I installed (I read somewhere that it does).


  10. I saved a motherboard from the trip to the dumpster. It's from a HP machine and I can't find no info for it. What puzzles me is the front panel connector. It doesn't have the usual PWR LED, PWR SW, HD LED etc, pin header.

    There's only a six pin header labeled "FRCNT CABLE". So, does anybody know were I can find the manual or a way to figure how to turn this thing on? I just want the power switch pins, I don't care about the leds. Is there a way to trace it?

    I know the ATX PS wants pin 14 and 13 shorted to start, should it try to see if any of those is connected to the header?


  11. Hi guys

    the s/w im using is TurboCNC & JalaCNC, i also tried changing the states i.e. one phase, step inhibit, half step etc, for some reason it doesnt like it, stalls or vibrates.


    do you know if you hav 2 change the step to phase in TurboCNC?

    It's been a while since I last played with TCNC but a few pages back I've posted my config file. Take a look and see if it helps.


  12. Hi all, dont know if people still post to this but i need help. I have built the board, tested it and connected it, when in operation the motor is either 1 of 3 things:

    1: Jumpy and just vibrates
    2: Has direction but very slow and not much torque
    3: stationary but with strong holding torque

    Could someone please help




    When i tested it, i tested for signals from the parallel port and the 5V from the power supply, both of which work!

    What s/w are you testing with? As MP say, the pulsewidth is the most important thing to set.
  13. Guys, I don't think he asked for a VGA to TV converter. I believe he asks for a way to use a VGA card and a monitor without a PC! He said he needs the complete description of the VGA card i.e. how it works inside in order tho figure out how to control it.

    Now that seems almost impossible to me and even if you make it work it still isn't a TV tuner, just a video generation system.


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