mcpublic

Member Since: May 1, 2009

Country: United States

  • Tool prices vary all over the map. Usually you get what you pay for. Sometimes it is a matter of volume. When you’re Radio Shack you can dictate wholesale pricing. If every one of their stores stocks has one wire wrap tool in stock, that still a lot of inventory just to prime the supply chain.

    Wire wrapping lost popularity in industry, in part because 0.1" spacing packages are much less common, and in part because of higher clock speeds. But now that there are so many SFE modules and carrier boards now available, maybe the time is ripe for a return of wire wrapping in the DIY world. Businesses can afford to spend $100 on 3 PCBs, but hobbyists often can’t. Wire wrapping is a natural way to connect modules together.

  • Nice write-up! I’ve been doing stuff like this for over ten years, and even I learned a thing or two, and/or you presented your lessons-learned better than I might have. You are more than half-way to creating an entire course on how to build reliable, maintainable installations for museums and elsewhere. (I know this is about a year old; did you create a course, perchance?)

  • The diode works like a surge-protector. It is super-important if you are going to drive the motor using a microprocessor, motor controller, or transistor. Without the diode you could easily destroy these. (It’s no fun toasting your Arduino). You don’t need the diode when driving the motor directly with a battery, or through a switch.
    Most microprocessors have relatively weak outputs (20-25mA). The 33 ohm resistor in series is there so the motor doesn’t draw too much current from the microprocessor. It’s not needed if you are using a motor controller.

  • Two alkaline batteries in series will will work great. A single lithium “button” cell (e.g. a 2032) will work too, but it won’t last as long. No software required.

  • To make an ROV thruster, all you have to do is remove the impeller, and attach a model-boat propeller to the shaft. I trimmed some of the plastic off to make it more streamlined.

  • I wish there was something I could to to help you guys out. It much really suck to be a small business being hassled by an organization like SI, that doesn’t seem to actually do anything productive. It’s a long-shot (they usually take on big, internet-related issues), but perhaps the EFF’s (Electronic Freedom Foundation) lawyers can offer some assistance. Anyhow, it looks like you have a pretty good case to defend yourself with. I hope SparkFun’s lawyers really socks it to them, while resisting the temptation to actually go to court (big bucks, long time, no fun!). …heck, sue them for filing a frivilous lawsuit… Good luck!

No public wish lists :(