PICMAN, A Diy Prototyping Setup

[Ytai Ben-Tsvi] wanted a rapid prototyping tool that could be easily and cheaply built at home. He came up with the PICMAN, a breadboard compatible PIC based board that has everything you need to get the ball rolling. He’s using a PIC18LF4553 which has built-in USB support that can be used with a bootloader for programming. The board also features a voltage regulator for non-USB power sources, some indicator LEDs, a user-defined button, and a reset button. The chip is on the underside and a combination of through-hole and surface-mount parts make for a one-sided PCB that can easily be etched using the toner transfer method. You will need a PIC programmer to burn the bootloader firmware the first time but once that’s done this becomes a self-contained package.

23 thoughts on “PICMAN, A Diy Prototyping Setup

  1. So that looks pretty neat, and something even my soldering skills *could* do.

    I was curious though, I read the article and I know it is on the to do list, but how come so many of these things use standard USB rather than mini USB?

    Aside from them perhaps being a little more fiddly to solder on, they offer up a huge saving in space and I seem to have far more mini USB cables (digital camera, camcorder, mobile phones) at hand than I do standard USB.

    I also have what I suspect is a very stupid question about the SMD components. Is it possible to use a hot air gun to solder these onto the board? Can the components stand up to the heat long enough for the solder to melt?

  2. I definitely agree regarding the mini-USB. It is a bit of a pain to solder, though…
    I’ve been using a simple ($40) soldering iron with a pointed tip and some good tweezers myself. I don’t know if a hot air gun would work. I’ve only heard of it being used to de-solder, but I’m not a soldering expert. I suspect that the 0805 resistors and LEDs might be blown away by the wind, and I’m not sure for how long they’ll withstand the heat, although I guess this is probably not very different than when using a soldering iron.

  3. Seems to me it’s really trendy to use 18f4550 family for prototyping boards these days. :)
    Nice though, a great example of simplicity. I’m ashamed of my board now, which uses tape cables for connectors…

  4. @chango – thanks for sharing. That was pretty useful. Time to upgrade from my current paint stripper – although in my defence I have to date been using it to salvage components from Scanner & Printer PCBs.

    Dropping the SMD component in with tweezers AFTER you get things all nice and warm was how I imagined it should be done, rather than dropping it straight onto cold paste. I guess the issue is this works out ok when you only have to drop in a small number of SMD components therefore you mitigate the risk of baking the board completely.

  5. “but how come so many of these things use standard USB rather than mini USB?”

    the to do list says use a mini B connector, the one in the picture is a mini A,the same as your camera / psp whatever, but its still tiny compared to a standard USB A or B connector

    so whats the issue?

  6. @tehgringe
    One likely problem with the heat & drop technique:
    A good solder joint requires BOTH sides to be up to temperature.. if you drop cold parts onto hot board and solder, it MAY stick, but it won’t be a good connection.

    I agree, but this is designed with a USB bootloader, so it won’t usually be necessary.

  7. @therian
    For programming via ICSP (e.g. for programming the bootloader) I simply wired the ICSP headers on the breadboard. The intended usage was not to do this a lot, but rather use the bootloader most of the time. Not sure, but I think ICSP headers might be challenging on a single copper layer.

    This is a mini-B. See here.

  8. I understand that it run off boot loader but you newer knew where bugs hiding and it one of PIC advantages that they can be debugged by 30$ pickit2 unlike over 100$ jtag so it seems sinister not to use it

  9. I’ve got a single layer board from a while back when I was using 18F4550’s — I managed to fit in an ICSP port, but the board was probably twice as wide as this one is, and not nearly as clean. It was more of a standalone board than a breadboarding breakout; now I wish I’d gone more this way. Very nice work, I love the design. Had I not *just* switched to AT90USB-series AVR’s, I’d give this design a shot; looks beautiful to handle. Kinda similar (though easier to make in-house) to the Teensy++ (which uses an SMD AT90USB1287 IIRC).

  10. ICSP header? Heavy-duty power connection? Zif header or socket for different chips?

    This board hardly seems novel or unique, it’s just a PIC soldered with a breakout board. I can do more with the chip demo board that came with the PICkit 3 programmer.

  11. P.S. guys, stop being whiney babies and buy real soldering gear. Less than $200.00 for a complete proper SMT soldering setup.

    hot tweezers and a real SMT soldering iron is not that expensive and honestly is far easier to do than TH out of date junk.

    Plus you get a near endless supply of parts by grabbing old dead motherboards.

  12. @Osgeld: “the to do list says use a mini B connector, the one in the picture is a mini A,the same as your camera / psp whatever, but its still tiny compared to a standard USB A or B connector”

    That’s not a “to do” list, it is “ideas used in the design”. The connector in the photograph is probably a USB Mini-B receptacle. (Mini-A is deprecated and would be used on a USB host, not a USB device. Your camera certainly has a USB Mini-B, Micro-B, or Micro-AB jack.)

  13. @fartface (nice name)
    I’m anti-arduino but I actually don’t mind the tiny oversized-chip arduino boards. It’s really no more than an AVR with some minor interface circuitry at that point, so it requires just about the same work as using an ATMEL chip in a custom circuit.

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