Simulating arc welding

Discussion in 'Photos & Videos' started by alex_mrrkb, Jan 24, 2003.

  1. alex_mrrkb

    alex_mrrkb Member

    Hi !

    On my N-scale layout there's a locomotive repair shop.

    I'd love to have a blue led blink randomly to simluate arc welding .. but I can't find on the Internet any circuits I could build (must have complete circuit, I can follow a plan but can't understand them).

    I've seen some for sale but are quite costly ... I've also seen this next one but uses programmable chip, but I'd have to pay to have the chip programmed :

    Anybody has a simpler circuit with common components, something a dummy like me could build ?

    P.S.: I don't need sound.

    Thanks !
  2. eightyeightfan1

    eightyeightfan1 Now I'm AMP'd

    Busch sells an electronic welder(Walthers 2002 HO scale Cat Pg857) for about $23.00US. Don't know if thats what your looking for but it might be a start.
  3. satokuma

    satokuma Member

  4. David Eaves

    David Eaves New Member

    Hi Alex

    I'd be happy to help, you can do it reasonably simply and cheaply it won't be as spohiscated as the site in the link but will do quite well. I made a flickering bonfire with the circuit I have in mind, with a bit of variation you can make it work more slowly to simulate the welder

    A few questions..

    How often do you want it to fire up. (Eg on for 3 seonds off for 20 with some variation)

    Have you done any construction before, I'll know how much detail I need to add the to diagram.

    If you post the information I'll post a circuit diagram

  5. alex_mrrkb

    alex_mrrkb Member

    Humm ... let me think ...

    First, the flickering should be random, or at least "look" random ... the duration of the fliskering (and pause) should also be random. A good cycle would be:
    • Random flickering for (1 to 10) seconds
    • Pause for (5 to 15) seconds

    Some welder simulator out there uses a blue led for the welder and a red led to simulate hot metal, but I don't need this red one. Some other circuits seem to use a blue led and a white led, I wonder if the effect is better with this or not.

    My construction abilities? not too bad :) I can easily follow a good wiring circuit, assuming that every element (chip, resistor) is labeled and it's values are written somewhere.

    Thanks a lot for your help !!!
  6. David Eaves

    David Eaves New Member

    Okay cool

    I'll have to work out some component values and I'll draw the circuit out, I'll probably have a fiddle later this evening and post it either later or tomorrow.

    As regards the blue/white led if you like to start with I'll draw something out that uses one LED, then if its not that good we could add extra complexity. I was thinking about it and I decided that 4 chips will be needed (Maybe 5) heres a basic idea of the components needed other than someting to make it on (Do you have any breadboard/prototype board to build it on to try it to start with I'd recommend getting some if you haven't. That way it will be easier to develop)

    2 x 555 timer (Or one 556)
    2 or 3 4017 Decade Counters
    1N4148 Diodes
    + Various Resistors and Capacitors
    Maybe a few basic NPN trasnistors (BC184 or BC108 or similar*)

    If you do have to buy them I'd get more than the quanities suggested in case of accidents. :)


    PS Do you have a regulated 5V or 12V supply available, if not what is the value of the unregulated volatage out of your track controller.

    *Do they mean anything to you, I can always look up the part numbers that would be suitable I know there are a few numbering ystems around the world
  7. jon-monon

    jon-monon Active Member

  8. alex_mrrkb

    alex_mrrkb Member

    This is great !! Thanks for your quick response ! I look foward seeing a plan !

    For the components, I already have many 555, the decade counters, diodes and resistors. I have all this stuff because I've built the traffic light controler designed by rob paisley. All I need is the capacitors ans transistors.

    About power suply, yes I have the regulated 5V or 12V needed, in fact, I use a computer power supply to drive my traffic kight controller, and later my signal system.

    Thanks again !
  9. Vic

    Vic Active Member

    Hi Alex, This guy sells an industrial welder flasher unit for $19.95 that uses a blue/white led and a really nice timer circuit. I have one and I'm really impressed by the quality of his workmanship and his components....I've built several of the welder flashers from projects in mags and none ever worked as well as this one nor appeared as realistic.
  10. alex_mrrkb

    alex_mrrkb Member

    And for the breadboard, yes I have that too :D

    You see, I love electronics, but I just can't find the right book to learn all this stuff. I can figure out the basic things, current flow, resistors, diodes, basic chips (timers, AND, OR...) but connecting all these togeter is a complete mystery !!!
  11. shamus

    shamus Registered Member

  12. David Eaves

    David Eaves New Member

    Hi Alex

    I've included a link to a hand drawn diagram its an LZW TIF so its only about 30k in size.
    If you have any problems with the file just ask, and if you can't read it etc.. :)

    Circuit Diagram

    This is a basic circuit if you get this working extra bits can be added to make it more random improve etc.. However I think its best to start more simply. I think building this should help your understanding. Heres a basic description of the circuit.

    The first 555 circuit runs at about 0.1Hz (5secs on 5sec off) this makes the clock to the first 4017

    The outputs of the 4017 are connected together to make OR gates, when these outputs are on the welder will be on.

    You can change these around as you like to change the timings, also if you change the capacitor on the 555 you can change the speed. The one with the capacitor and resistor adds an additional delay (As the Capacitor charges) on one to give a bit more variation. The trasnsitor acts as a NOT gate. You can omit this if you think in reverse and change the diodes around, you will need more diodes for this though.

    The second 555 runs at about 0.2Hz you can change this as well, you might want to make it go a bit faster. This makes the clock for the 4017, again the diodes act as an OR gate to stop backfeeding

    Then these are connected to the LED via resistors. I have added the forumula to calculate the value. and the approx minimum and maximun values for a blue LED. What you can do here is change the brightness of the arc.

    Say you make R1 and R2 47 Ohms you will get a bright flash then off and another bright flash. You might want to then make R3 200 ohms so it will be duller.

    More sugtested values, (I'd play around and see what you can get that looks good)
    R4 47 Ohhms
    R5 470 ohms
    R6 270 Ohms
    R7 100 Ohms

    While it is on now you will get flashing.

    Okay this is a start its only basic you could do a lot more with a PIC like a lot of the ciruits use, if I was making it myself I would probalbly use a PIC they are so much fun to program and cheap. However I still enjoy fidlling with circuit like this.

    Construction tips, make the 555 circuits and check they work with an LED on pin 3 the output (Don't forget the resistior) Then move onto the 4017s in testing you can use more LEDs to check for signals.

    If you want you can connect some of the 4017 LED outputs to a white LED so you get a mixture of blue and white.

    Okay have fun, it should work though I haevn't actually built this exact circuit but have made many before like this that do similar things. Any problems don't hesistate to e-mail me.



    On the diagram the resistor above the transistor should be 1k
    And the 470uF capacitor on the first 555 should probably be 220uF or maybe 100uF (I made a slight mistake in my initial timing calculations)
  13. alex_mrrkb

    alex_mrrkb Member

    Thanks David !!!

    This is too cool !!!

    Thanks a lot David, I can't wait to get home to try this !

    The shame is, I wont be home until saturday night ... I'm not sure if i'll be able to resist all this time ...

    Have a nice weekend everyone !!!

  14. alex_mrrkb

    alex_mrrkb Member

    Hum ... now THAT'S interesting ...

    Could you tell us a little bit more about thoses PIC ? I know about them, what they are and what they do (programmable chips) but what do I need to build this kind of circuit using a PIC ?

    What I like is the idea of "programming" the chip ... I am myself a computer programmer and a little bit of C or assembler will be kid's stuff for me.

    Any good links for us ?

    Thanks !

  15. David Eaves

    David Eaves New Member

    Well its funny you asked, I was looking at your website and thinking I ought to suggest that you look into PICs. As I had guessed you were probably a computer programer due to your webcam page and also the fact that yout site is written in PHP.

    Right PICs the best place for PIC information is you can get datasheets and, download the MPLAB sofware (Free)

    PIC wise the best chip to start with is the 16F84, they are cheap (I can get them for £1.80 each) and are idea for this sort of thing (Thats what those ones you can buy are using) They are electrically erasable so you can program them as many times as you like.

    You also need a programer, you will either have to buy one there are loads on the market. I don't know what electronic companies you have got in Canada but if you look in places that stock electronics you will find loads.

    I actually made my own from this circuit,

    I can make PCBs at home so it was cheapest to do it this way.

    You also need software to program the PICs I use the software from this site

    To start with the great thing is you can use the software to program with the 16F84 for free.

    Right now that is all you would need to get going, you can write the assembler using MPLAB and then compile it. I started this way but found it takes ages and the code is hard to maintain.

    I now use the C compiler from

    I really like this compiler and there is lots of info about it to get you started. With this C compiler you could write an Arc Welding simulator in about an hour. If you do get set up for PICs, I can give you a few hints how to achieve what you would want to do with a PIC, and a bit of code to do things like PWM.

    There are other compilers around as well, there will beloads lurking on the web about them so you could find the most economical compiler depending on what you can get locally in Canada.

    Okay hope this is helpful

  16. Mr Foxx

    Mr Foxx New Member

    Scale Flashing Arc Welding Simulator: The simplest, cheapest to build a Flashing Arc Welding Simulator, just take a old 9 volt transistor radio, I got one from a yard sale for a $1.00, Replace the speaker with LED on extended wire (I used 20 gage wire, Smallest I had on hand at time) , turn it on & tune station knob, adjust vol, till a satisfactory random flash is achieved. NO timers, NO spacial boards to build, or programmable chips, computer control (over kill for a flashing bulb) I have 2 LED's on one radio, I spent a whole 35 Min's putting it together including refilling my coffee cup. Mark Twain said: "We spend so much time making something so hard from something that was simple" I have set one in a forage & other at a welder, the random flash is more realistic that any high $$$$ sym, i've seen. Happy R/R
  17. MasonJar

    MasonJar It's not rocket surgery

    Mr Foxx,

    Welcome to The Gauge! Great suggestion too... :thumb:

  18. yellowlynn

    yellowlynn Member

    That simulator sounds fantastic. Seeing as how I know diddley-zilch about that stuff, a few questions. Does it have to be 9 volt? Would any transister radio work? Etc., etc. I'll keep my eyeballs open at yard sales from now on.

  19. Mr Foxx

    Mr Foxx New Member

    I find this works best (low voltage) a battery eliminator can be used, but these tend to get warm being left plugged in all the time. So I installed a off/on switch at battery lead so I won't need to readjust vol/off knob all the time. the unit it-self sits near main control panel & if I forget to turn it off? so what, battery gets low, replace it .50 cents? generally any radio should work (I don't recommend using the family home stereo /Boom box. Besides if it go's bad how much are ya out of pocket?, most of my room size 9x12 HO Layout is modular units, that go around 3 of the walls with a 33" island rail yard. The radio I've been using for almost a year now. I have e a red LED in the forage & Lit-Blue one at welder. the yellow ones don't look good, looks like a dim white. try different things, experiment, see what works best for you needs. post some up dates. :) "Minds are like parachutes. They only function when they are open." No limits to what can be achieved

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