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Member Since: February 3, 2010

Country: United States

  • The link in the Documents section named: “Datasheet (TB6612FNG)” to https://cdn.sparkfun.com/datasheets/Robotics/B6612FNG.pdf is dead.

    The correct URL seems to be https://cdn.sparkfun.com/datasheets/Robotics/TB6612FNG.pdf

  • Now you’ve got me thinking about using a Noga-style arm like this: http://www.shars.com/products/view/1456/Test_Indicator_Holder_Arm_Only

    I don’t know how well the no-name clones compare to an actual Noga, but it’s something to think about.

  • s/slightly larger than/twice as big as/

  • Can this thing be trusted to stay shut off if unattended? I’d like to set up an automatic irrigation control, but I’m paranoid about a valve like this failing and losing megagallons of water before it’s shut off.

  • Schottkys provide better back EMF protection than 1N4007 power diodes. Switching time is much faster. Looking at the Motorola datasheet at http://www.rose-hulman.edu/~herniter/Rose_Classes/ECE250/notes/ECE250 Diode Switching Speed.pdf, 1N4007’s have about 5 us recovery time and 1N4001-5’s have about 3 us. You can swap in 1N5819’s for the 1N5818’s if you need 35V operation.

  • Success on the “hack it to work” front. I elongated the holes using a cylindrical carbide burr, maybe 3/32" dia, in a dremel tool. After 5 minutes or so, the holes were about 1/16" longer and the servo fit perfectly using 5/16" spacers.
    You start the tool, carefully bring the bit into the hole, and then pull it against the side of the hole away from the claw. Hold it tightly or it will chatter and get away from you, and potentially shatter the bit.

  • Follow-on–even though I was able to get the claw on the servo by omitting the spacers, the servo stalled out because of the misaligned gears.

  • Yeah, the mounting holes are about 1/32" out of place. 5/16" spacers are an exact match. If you look closely at the photos the mounting screws are using two nuts, no spacers, and bowed out a bit. If you mount the servo in place straight there’s no room for the control horn between the shaft and the round end of the slot. Time to get out a small carbide bit and the dremel to elongate the mounting holes a wee bit.
    As far as the servo shaft mount goes, you want the control horn, not the disk. The two inner holes on the hor match the proved holes exactly.

  • Ideally, yes. Often what happens is a race to the bottom, where manufacturing gets pushed out to whatever country has the worst labor and environmental standards.
    RoHS compliance misses the mark, since a product could be made using the nastiest stuff imaginable–cyanide for gold extraction, benzene as a cleaning solvent, etc–and yet still meet RoHS standards if the finished product doesn’t contain the forbidden substances.

  • Hmm, have the outlet since I put in a gas range. Too bad I don’t have a truck and a 50A extension cord.

No public wish lists :(