FPC Arduino

Seeed Studios has a new version of the Arduino that they’re calling the Seeeduino Film. Instead of the traditional fiberglass substrate they’ve used a resin material to produce a Flexible Printed Circuit (FPC). In addition to its flexibility their aim with this prototype was to keep it modular. From what we can see each of the four squares is a different component in the Arduino system. The photo above has the USB interface on the nearest node, then the power regulator, the microprocessor, and finally the remaining peripheral connections. This material can easily be cut with a pair of scissors so the programming section can be removed once the firmware is burned to the chip. It will be interesting to see final pricing and package options. We wouldn’t mind having an FPC ATmega168 breakout board around, but specifially this would fit nicely in a watch band if you were building your own wristwatch.

[Thanks Juan]

30 thoughts on “FPC Arduino

  1. Is there any resource out there for making FPC’s in hobby environments or must you get it custom made by a manufacturer?

    I don’t see a point in buying it unless I can make add on components that are bendable too. Someone please school me if I’m out of line.

  2. Id like it if they added a series of contacts or something that would allow the programming square to be reattached, you never know when a bug will rear its ugly face.

  3. I can see how this would be good for wearable computing. I’d bet the prices are good, too, since Seeed is always very reasonable.

  4. @Garret
    It looks like they did. If you look at the picture, there’s a beige/gray plastic part between the two middle ‘nodes’.

  5. I hope they modify this board to use rigid backings. I’ve done a bunch of work with flex circuits and I’m forever worrying about flexible boards fatiguing solder joints on components close to a bend.

    Here it looks like they’ve just stuck a QFN part in the middle of their board without any strain relief. Now, being in the middle is much better than being on an edge, but from the looks of it, there’s still some bend in that board. I’d be keen to see what kind of life-time they get out of it.

    Remember kids: always strain relieve your wires/flexures and winners don’t do drugs.

  6. Even though this is an Arduino, I am glad to see that this kind of “PCB” is finally becoming available to even us – the DIY community – to work with.
    Maybe Seeed will start a PCB service like their “Fusion” for this flexi-kind PCB so we can make our own funky curved ones.
    I’ve seen this kind of PCB in a GPS tracker inside a shoe, somewhat recently.
    Anyway, this is far from classic Arduino board which is meant for prototyping so this Arduino can actually be in a final product… I guess.

  7. I’ve lost track of the design ideas I’ve had that lost steam after realizing that there’s no hobbyist source for FPCs.

  8. @Regulus
    Me too, instead of cutting the first square off you can just disconnect it in the middle. Then you just need some sort of power supply square to plug in, unless the power pins are broken out on the microcontroller square

  9. It looks like they are using a 20 pin bus so effectively, you could cut away the programming bit, and then plug it back into the ┬ÁController bit later, if/when you need to.
    side note, yes, my keboard does have a ┬Á key.

  10. Oh, and a quick note to folks who don’t think they can get their own flex or flex-rigid boards – you can, you just need to leave it to the professionals. I get mine made at Storm Circuit (a Chinese PCB house), and I’ve had good results, even with very fine pitch designs. Just add an extra ‘flex’ layer in your Eagle cad cam setup and the wizards there will work it out. Minco has a really terrific primer on designing flex boards.

    If you’re worried about strain relief as I’ve mentioned in an earlier comment, you can go flex-rigid, but it’s more expensive than regular boards. In my experience I’ve been able to produce prototypes out of flex that saved me substantial money, and rigidised flex is even easier. Save the fancy stuff for when you really need it!

    And no, flex boards aren’t as cheap as Sunstone or PCB express or whatever short-run company you prefer by dint of the fab company requiring serious manufacturing gear and overheads, but it’s competitive and relatively affordable. I got a baggy of 200 flex boards (15 mm x 10 mm, at 0.1 mm tracks + spacing) for $250. I consider that a bargain.

  11. Awesome. This could actually greatly improve something I’ve been working on, if only the ribbon connector were also flexible. I need to fit a uC into a thin tube, curved into a taurus. As long as the ribbon connector is rigid, however, I’m just going to have to go with current plans.

    Seeed: I need flexibility in both directions! Can we get a flexible connector or solder tabs?

  12. Seagate used to use film-layer PCBs to make certain models of SCSI hard drives. It allowed them to make certain parts of PCBs to be flexible.

  13. Ah ha, just the form factor for a model rocket or HPR flight computer, wrapping around the inside of the tube. Just add hot glue to hold everything in place.

  14. has anyone attempted making their own fcbs? assuming i can find a suitable bonding agent, is there a reason why copper foil bonded to something like an overhead transparency couldn’t be etched the same as a standard homemade pcb? i’m sure that the transparency material isn’t ideal, especially to be soldering onto, but there has to be something we can get our hands on that would be worth experimenting with.

  15. @j s Just about all hard drives have a flexible PCB inside that goes between the bulkhead connector for the logic board and the heads. Usually there’s an amp IC and a couple of discretes somewhere on that FPC.

  16. @dioxide: you can sometimes find raw flex PCB material on eBay (search for ‘copper clad kapton’ or ‘Pyralux’). Etches just like regular copper-clad board. Unfortunately it can be expensive as hell. Also, pcbfx.com has been promising reasonably-priced material for the hobbyist market for months now but has yet to deliver. The anticipation is deadly!

  17. As mentioned previously Kapton bonded to copper works well. I used to make heaters and it worked well for high wattage heaters . One even boile water in a coffee mug in less than 30 seconds. The kapton and copper need to be put in a press and heated to bond.

  18. You can get samples of Pyralux directly from DuPont. After that, just follow whatever method you usually use for hobby PCBs. I did a test board using the toner transfer method, and it worked great.

  19. Like much in the makeohackosphere, this product will profoundly disappoint the very people who are most excited by it.

    What flex is primarily good for: 1) routing cables through hinges and other rotating assemblies (wheel mounted controls on cars are routed through a really cool “clock-spring”) where the range of motion can be limited. 2) cramming circuitry into really, really tight spaces.

    For years the canonical application was cramming circuitry into things like film SLR bodies. If you ever take anything apart that has flex circuitry inside, you’ll see any portion with components on it is rigidly held.

    You don’t actually want flex to flex. That is, it shouldn’t flex much and it never should flex without appropriate strain relief.

    That said, this thing will at least give arduino fans an introduction to the limits of flex circuits!

  20. @Eric – Dude, great idea. They mention it’s chain-able. Would be interesting to see which pins are on the connector and how many layers it is.

    @Wiggins – That beige/gray connector is called a “ZIF Connector” Zero-Insertion-Force.

    @dioxide – FPC = Flexible-Printed-Circuit. This is not a FCB, do they even exist?
    The substrate is Kapton. You can buy rolls of Kapton tape, its expensive but its heat resistance enough to solder onto!

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