Herman the German

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Everything posted by Herman the German

  1. ::)I found a strong DC motor which I want to use to drill PCBs. It has a tacho-generator output which I think can be used to automatically control a preset rpm. On a varying load the motor rpm will decrease or increase. It should also be run on 24V for maxium power to give at least 20.000 rpm. Does anybody have a circuit ready to achieve control? Thank You. HtG
  2. Please help identify this logo!!

    :D This logo is Hirschmann connectors Germany. Take a closer look it is a male deer. (Hirsch is a male deer). Also check hirschmann.de regards Herman the German
  3. Timer

    A very good idea. maybe I can handle the hardware but not the software. The other way with wired logic is easy to understand and also easy to trace in case of malfunctions. I have made a lot of control units for industrial purposes, but never used a Microcontroller. Wired logic is just my thing! Even using a full size 19" rack with up to 17 PCBs doesn't bother me at all. Boole's algebra is logic. A small piece of (SMD mounted plastic or ceramic) is not logic and will become as intelligent as the programmer is. sincerely HtG
  4. Timer

    Hello ante, I wonder why a *.sch (eagle) cannot be uploaded. The file has a size of 78 KB and I think Your mailbox can handle that size. Please send me an email to hjzelec@freenet.de and I will return the schematic. Thank You kind regards HtG
  5. cpu cooler

    ;)Peltier elements are not the right thing to cool a CPU. If You want excellent cooling You must use a water cooling system similar to engine coolers in cars. They are available in many electronic shops in Germany. Try CONRAD.DE. Of course they are very expensive too because of all the safety precautions not to flood Your PC. Peltier elements can produce 60 degrees of temperature difference between both sides. They take a lot of energy and do not only produce cold but also very hot sides of the module. To get rid of the heat You will have to employ a big fan and a very big heatsink. A small element is normally rated 2,5A at 12 to 14 Volts. And this element is NOT enough for a (overclocked?) CPU. Regards HTG (Herman the German)
  6. Constant current source for a low Ohm load

    Please check at ELV.DE. As far as I know they offer a programmable current sink for a widespread band of operation. Don't sink too much current - otherwise You will have to buy an own nuclear power plant to cool the device properly. The german word for this device is: Programmierbare Stromsenke Regards Herman the German
  7. UV exposure box

    Yes, I can do! The film or whatever You use to expose Your future board likes parallel light very much and the more even the light is distributed over the entire board area the better will be the result. I built a box when I lived in germany (now Thailand, the no-have country) I used 6 fluorescent lamps Type TL29D16/09N and kept the spaces closer than 1 inch. Before I built the box I metered the light and gaps greater than 1 inch are absolutely the worst You can do to Your box. 15mm (1inch=25.4mm) is the best to do. You have the light almost parallel and enough room between the glas tubes for cooling. UV-A produces more heat than white light. If You use aluminum foil on the bottom of the box (not straight and even, just a little bit crunched) You will increase the reflections but don't do too much of crunching because reflections will penetrate the film slanted and that means unwanted exposure. Check the film side at the photoresist, closest contact. Printing on the wrong side has to be avoided under any circumstances. Have a good time building Your box. Best regards Herman the German P.S. I am about to build my box soon but this one will almost be unafordable in EUROPE since I will make it from Teak-wood (only used on ships and extravagant furniture)
  8. PCB photofabrication

    Here is another suggestion but I am sure it will work with Your system as well as it works with mine. I am using EAGLE and for best printing results I use the solder and the component side (solder side is blue and component side is red). On the screen they look violet but on the paper they are just black. That means to make an extra copy of Your layout just for printing purposes. Copy all traces onto the component side and the print will be deep black (as black as a road tunnel at night) printing both layers at one time. There will be no loss of the sharpness conerning traces, pads and vias. There is a good chance to fill unwanted holes on the solder side with colour on the component side. I tried this also on a colour laser and very much to my surprise there was no significant difference. For the developer I use "Aetznatron". Sorry I don't know the english word for that but the development is finished within 30 seconds. Any longer development will also erase the photoresist not exposed to light and You'll have a clean copper surface. The solution is 10grams per one liter of lukewarm water. 30 degrees will just be fine. Don't use higher temperatures. The result is unpredictable.
  9. Timer

    ??? I did NOT want to know that, wise guy!