February 27th, 2005, 09:22 AM | #1 |
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Homebuilding A Jib -- Parts Sources?
I'm working on engineering a homebuilt motion-controlled jib arm. I've more or less worked out the physical design, but I'm having difficulty sourcing certain parts.
More specifically, I need to locate a supplier for four decent DC motors (4-12v preferred) and gearboxes to provide around 4 newton-meters of torque at 1 RPM (or maybe 1 newton meter @ 4 RPM, which I can belt to the driveshafts to get the last bit of power..). I've looked into McMaster-Carr, who have industrial-type large motors, and Edmund Scientifics, who carry all tiny little hobby stuff. MicroMo looks decent, but they don't do retail sales. Can anyone offer any suggestions? I know that the homebuiltstabilizers forum is probably a more appropriate spot for this question, but they seem to be more or less dead these days. [edit: okay, looks like my thoughts of HBS's death were very premature. But I'm still curious if you folks have any input..] |
February 28th, 2005, 10:17 AM | #2 |
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Hi Ryan,
Herbach and Rademan will probably have what you need: http://www.herbach.com/Merchant2/merchant.mv?Screen=SFNT&Store_Code=HAR Just out of curiosity, what speed controller are you using? And why would you need 4 motors? Pan and tilt are 2 directions = 2 motors. Dan www.DVcameraRigs.com |
February 28th, 2005, 01:10 PM | #3 |
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Re: Homebuilding A Jib -- Parts Sources?
<<<-- Originally posted by Ryan Spicer : ...I know that the homebuiltstabilizers forum is probably a more appropriate spot for this question, but they seem to be more or less dead these days.
[edit: okay, looks like my thoughts of HBS's death were very premature. But I'm still curious if you folks have any input..] -->>> It has it's days but certainly not dead. If you don't post you wont' get an answer.
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March 1st, 2005, 10:28 AM | #4 |
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Charles, I appologize for my premature dismissal -- I had just looked at the Cranes & Jibs forum, and noticed that two of my posts from last August were still on the front page. But then I noticed that there were some more active comments currently, so I decided to check it out. My post's been made, and I got a couple of useful links.
Dan, I'm using 4 motors because I need to computer-control the yaw and pitch of the jib arm as well as the head. I'm hoping to have the jib set up for full computer control, so I can repeat the same move identically as many times as needed. As for a motor control, I haven't decided yet. I know a fair bit about electronics and I'm always up for teaching myself more, so I'm hoping to roll my own using an Atmel AVR microcontroller and some high-amp-tolerance transistors for PWM (pulse-width modulation). RS232 serial in, 4x PWM output out. If I can find an off-the-shelf solution that does what I need at an affordable price, I'd consider it, but I'm a student, so my time's cheap and my wallet's relatively empty. ;) I'm working on adding computer-control to a pre-built pan-tilt head for one of my theater tech classes, and in that case I used two 2-amp MakingThings "teleo" motor control modules because they were in the department's budget, simple to set up, used USB, and interfaced directly with MAX/MSP, the software they love over there. Since MAX/MSP is $500 and three teleo boards (two motor controllers plus the hub board with the USB port) cost $450, I don't think I'll be going that route here, as nice as it'd be. |
March 1st, 2005, 10:46 AM | #5 |
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Hi Ryan,
That sounds really amazing. An old friend of mine invented "Hot Keys" which has become an industry standard for motion control. I've tried to pick his brain about it with no luck. I probably wouldn't understand it anyway! Yeah, controllers are pricey, so best to do your own if you've got the skills. Did you check out Herbach and Rademan? They've got tons on stuff! For the larger motors you might look into wheel chair motors. I've seen them used for pretty cheap. Dan www.DVcameraRigs.com |
March 1st, 2005, 07:40 PM | #6 |
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Dan, yes, I checked out H&R -- this (http://www.herbach.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=HAR&Product_Code=TM01MTR4524) looks pretty great, although I was hoping to get away with lower than 24 volts. I forget where I found Skycraft Surplus, but this motor (http://www.skycraftsurplus.com/index.asp?PageAction=VIEWPROD&ProdID=450) looks very good as well. I need to talk to some campus organizations about grant money -- can "building something I've never personally built before" be considered undergrad research? I sure hope so. ;) After I know my budget for sure I'll start nailing down details.
Also, my advisor got me looking at www.opalkelly.com, which sells FPGA boards. Very interesting stuff, although I'm not sure I know enough about the FPGA world to make use of any of it. Might be worth a look, anyway. |
March 2nd, 2005, 09:31 AM | #7 |
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Thanks for the link!
Dan |
March 2nd, 2005, 02:13 PM | #8 |
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Ryan, can you please share why go with DC and not with steppers?
I ask because I kind of decided on steppers...
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March 2nd, 2005, 06:04 PM | #9 |
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Cosmin,
I went with DC servos because I'm planning to build the control circuitry myself, and I understand how to operate DC servos far better than steppers. I think steppers may well be a better solution, but I can't afford to buy the control gear right now. I'd be interested to hear what you worked out in terms of controlling steppers. |
March 2nd, 2005, 06:33 PM | #10 |
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Might have a possible source for you, Ryan. I was in a little electronic surplus shop in Pasadena today and they had a ton of motors and gadgetry that might help you out. I'm not a whiz at electronics so I'm not sure they have what you need, but they do have really, really good prices.
The store is C and H Sales Company, Surplus Materials. They're on East Colorado Blvd. in Pasadena and their number is (800) 325-9465, or (626) 796-2628. Tell 'em what you need and maybe they can help.
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