Thanks to a fellow builder, I've ordered some parts and pieces today that will make piecing together the feet a bit easier.
Jerry Chavalier shared his configuration for the center foot. Rather than using the omni-balls, which are rather noisy on any hard surface, he provided the group with a readily available caster. This one is a 2.5 inch one available from any Home Depot. I forgot the SKU but can re-post it later (or you can ask Jerry). His mod was to remove the plastic wheel in that caster and replace it with a 2.5inch rubber tire from McMaster Carr (part # 2829T15).
While shopping around McMaster Carr's site, I noticed that they sell caster axles. Since the wheel has a 3/8th inch hole, I found a 3/8th inch axle bolt (23595T14). Upon receiving the parts today, the axle is a bit too long, but I am pretty sure I can shim that up to make it snug. (I'll follow up this post with some photos)
By next week I'll tackle sawing the old axle out and removing the plastic wheel. Then get into replacing it with the rubber wheel. Jerry provided a few good pictures to demonstrate how the casters fit inside the center wheel. It looks like minimal drilling into the pre-existing plate that held the casters.
He was also kind enough to share with me the website and part number for the belts I need for the JAG NPC Footdrive. Several builders have noticed that the belt is a tad long, especially since it comes into contact with the knurled detail pieces.
In case you are in need of the shorter belts, they are available from http://www.sdp-si.com . The part number is A 6R55M065150. You will need to get into their online store before you can search for the item. I bought two, with a grand total of $27, then $12 shipping. I'd groan about the shipping costs, but with diesel fuel prices soaring, that's not a terrible fee.
So once again I have all the accessories. I just need to break down and buy the NPC motors! However, I have a few other parts I have committed too that are ready to be paid for. Another set of battery boxes, holoprojectors and another center foot are all set and ready!
Again, not much progress news but I thought I would share those part/piece sources in case others needed them.
Til next time!
Thursday, March 20, 2008
Friday, March 7, 2008
More researching!
Well no pictures this time around, as I have been busy figuring out what kind of PC will go inside my droid. I've had a lot of fun researching this, asking friends, coworkers and computer geeks from the various forums I frequent.
Initially I leaned towards mounting a laptop inside of R2. But several things make that unattractive.
First, to borrow from Don Martin of the MAD Magazine cartoon days....the FWAAAAP! BANG! ZZZPPPPT! factors. That is, the ability of a modest priced laptop to handle the jolting and jarring motions of being inside a moving droid. While a lot of accomodations could be made to cushion the laptop, that also makes for another problem: access. When the battery is dead, you have to either find a way to snake a power cord in there, or remove the unit. Other problems were size, where to put it and so forth.
Someone tuned me towards the automotive PC crowd. Lot's of people are playing their MP3s and other digital media in their vehicles with DC powered computers. These systems use Mini-ITX motherboards and have intelligent power systems that automatically power down when battery power is low. (Who wants to crank their tunes only to find they can't start their car!)
Before I got too far ahead of myself, I jotted down the priorities for this computer:
Initially I leaned towards mounting a laptop inside of R2. But several things make that unattractive.
First, to borrow from Don Martin of the MAD Magazine cartoon days....the FWAAAAP! BANG! ZZZPPPPT! factors. That is, the ability of a modest priced laptop to handle the jolting and jarring motions of being inside a moving droid. While a lot of accomodations could be made to cushion the laptop, that also makes for another problem: access. When the battery is dead, you have to either find a way to snake a power cord in there, or remove the unit. Other problems were size, where to put it and so forth.
Someone tuned me towards the automotive PC crowd. Lot's of people are playing their MP3s and other digital media in their vehicles with DC powered computers. These systems use Mini-ITX motherboards and have intelligent power systems that automatically power down when battery power is low. (Who wants to crank their tunes only to find they can't start their car!)
Before I got too far ahead of myself, I jotted down the priorities for this computer:
- Intel Core Duo CPU. No VIA CPUs. We want the CPU horsepower for the applications we'll be creating.
- Low power usage. Since the computer we build will require a seperate battery, we need to balance power and performance.
- Flash Drive. Rather than utilize a conventional laptop hard drive, I want a 8 to 10 gb flash drive. These have no moving parts, solid throughput (although less than SATA) and low power usage. Additional space can come via USB Flash/Thumb drives if needed.
- OnBoard video, sound, RS-232/Serial Port, Wireless LAN and USB ports.
If you think such a system is a rarity, its actually not. The fine folks at LogicSupply.Com have been excellent, answering all of my questions thoroughly and professionally. I'm still tweaking the details of what I need...but its nice to know that there are vendors like these folks who have some great advice.
Monitor? Nah! My co-worker has a Mitsubishi PK-20 DLP projector, which would fit PERFECTLY in a holoprojector. (Daniel's Droidstuff.com displays one in this type of configuration) And even better, the projector is powered by a battery pack. How sweet is that?
Off course, making all of this fit inside a droid with 2-3-2 will be a challenge. But no more so than trying to code a application that will talk to the motor controllers, the USB Servo controllers and who-knows-what-else I think up.
That's the latest...hopefully some more meaningful progress...and photos...soon!
Subscribe to:
Posts (Atom)