Hex Crawler Questions
I'm finally finding some time to upgrade my hexcrawler (original version..) to the R/C control version that was featured on the Parallax (and I think CrustCrawler) sites for quite awhile. Not sure if the project documentation is still out there, but will be glad to attach it if not.
My questions revolve around the most efficient way to power this thing, as you have the usual servo/BOE/SSC needs, and then, and RC rcver, and some wireless cam stuff. Hoping to get some opinions, and maybe some insight from anyone who has already been down this path.
1. The doc shows the use of two 7.2 batteries, in series, (rechargeable, same as used for the servos..) to power the camera and xmter for the camera..essentially, the video system. It also shows the BOE hanging off of one of the 7.2V batteries, which leads to two questions...
a. SSCs also?..right now, I am using separate 9V batteries for the SSCs, and a 9V for the BOE...very kluged, but it worked for me to get it up and running. Gut says, these two 7.2V batteries can handle the Matco cam/xmtr, the BOE, and the SSCs...but, next question...
b. is it assumed one of the 7.2V batteries ALSO handles the servos?..if so, I begin to question the ability of that power source to do everything (though, it would make it a LOT easier from a clutter and wiring standpoint), and run for more than 5 minutes.
Is it assumed the servos get their own 7.2V battery, and two more of the 7.2V batteries are used as noted above?
2. These are standard 3000 maH NiMH batteries I am using. Right now, the servos run on one...does fine (I actually have the R/C portion of this thing up and running, though in a very temp configuration..)...wondering if...anyone has run the bot with two of the 7.2V batteries in parallel, or whether that is risking the "magic smoke" escaping from the servos..?
3. Another option I am lookign at is just running the cam and xmtr on a stack of 8 AA batteries..12V...wondering if anyone has gone this direction and can comment on battery life...(it is the Matco ASK2008TR, and the CNL-100C cam I am using..)...gut says, I may give up a little bit in battery life if I go this direction...
4. Minor issue, but..if I want to stick with 9V batteries for the SSCs and the BOE, I am assuming one 9V can run everything, even with the LCD App Mod on the BOE?...can't imagine the current draw being significant...
Ultimately, I plan to wire all the power and charging connections out to a small panel on the bot for convenience..so trying to consolidate power sources (and jacks/switches) as much as possible...
And let me tell you..it is sooooo nice to again have time to play in the "robot room"....so many projects..so little time...
Post Edited By Moderator (Chris Savage (Parallax)) : 10/5/2005 12:38:31 AM GMT
My questions revolve around the most efficient way to power this thing, as you have the usual servo/BOE/SSC needs, and then, and RC rcver, and some wireless cam stuff. Hoping to get some opinions, and maybe some insight from anyone who has already been down this path.
1. The doc shows the use of two 7.2 batteries, in series, (rechargeable, same as used for the servos..) to power the camera and xmter for the camera..essentially, the video system. It also shows the BOE hanging off of one of the 7.2V batteries, which leads to two questions...
a. SSCs also?..right now, I am using separate 9V batteries for the SSCs, and a 9V for the BOE...very kluged, but it worked for me to get it up and running. Gut says, these two 7.2V batteries can handle the Matco cam/xmtr, the BOE, and the SSCs...but, next question...
b. is it assumed one of the 7.2V batteries ALSO handles the servos?..if so, I begin to question the ability of that power source to do everything (though, it would make it a LOT easier from a clutter and wiring standpoint), and run for more than 5 minutes.
Is it assumed the servos get their own 7.2V battery, and two more of the 7.2V batteries are used as noted above?
2. These are standard 3000 maH NiMH batteries I am using. Right now, the servos run on one...does fine (I actually have the R/C portion of this thing up and running, though in a very temp configuration..)...wondering if...anyone has run the bot with two of the 7.2V batteries in parallel, or whether that is risking the "magic smoke" escaping from the servos..?
3. Another option I am lookign at is just running the cam and xmtr on a stack of 8 AA batteries..12V...wondering if anyone has gone this direction and can comment on battery life...(it is the Matco ASK2008TR, and the CNL-100C cam I am using..)...gut says, I may give up a little bit in battery life if I go this direction...
4. Minor issue, but..if I want to stick with 9V batteries for the SSCs and the BOE, I am assuming one 9V can run everything, even with the LCD App Mod on the BOE?...can't imagine the current draw being significant...
Ultimately, I plan to wire all the power and charging connections out to a small panel on the bot for convenience..so trying to consolidate power sources (and jacks/switches) as much as possible...
And let me tell you..it is sooooo nice to again have time to play in the "robot room"....so many projects..so little time...
Post Edited By Moderator (Chris Savage (Parallax)) : 10/5/2005 12:38:31 AM GMT
Comments
·· I added a subject to your post so you might get some responses.· Speaking of which, the reason the document you spoke of is currently not posted is that it's being revised.· The new Hex Crawler is built and has an S3 Pan/Tilt on it.· What we're waiting for is a new camera.· Of course, the docs will change, as well as the code and the schematic.· If two batteries are used in this one they will be in Parallel, not series.· The reason for two in series·in the original was a 12V camera.·
·· We're currently looing for a new camera that runs on 5 - 7 volts.· Once that is gotten we will post the new schematic, code and pictures.· The S3 will have both a camera and a PING))) sensor on it.· It will have an R/C Mode and an autonomous mode as well.· I apologize for the delay.· We should have something soon.· Stay tuned!·
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Chris Savage
Parallax Tech Support
csavage@parallax.com
I did a little searching for lower power cams, but did not find much..
I'll probably stick with this design, for now, though, the choice between R/C and autonomous mode is tempting...the hexcrawler is truly a project that never ends (which leaves my wife shaking her head...[noparse]:)[/noparse]...)..but my test engineer (4 year old) definitely likes R/C mode better...
Anyway...I'll wait to see what responses I get to my original questions....but look forward to the new design, even if, I never build it...
·· One big difference is that the Hex Crawler has been using the PSC instead of SSCs for some time now.· If memory serves, the BOE was actually powered from a 9V battery on the original Video Hex Crawler.·· I believe the SSCs were run from the BOE power supply, which was 9V.· There were 2 7.2V batteries, of which two created the voltage for the camera, while a center tap allowed one to power the servos.· So the servos did not have a separate 3rd battery.· Running two 7.2V batteries isn't really any different than running one from a "smoke" standpoint.· The main thing is two in parallel gives you double the current capacity (Almost).· One 9V can run the BOE, LCD AppMod, and Servo Controllers for awhile.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Overkill I know, but I have been powering the SSCs and BOE on 3 separate 9V batteries...that I can definitely consolidate. I'll either use one 9V, or tap 7.2V off the rechargeables.
I guess I'll try using the two 7.2V batteries as mentioned, and see what kind of life I get..
So if I am thinking straight here, I should be able to use two 7.2V batteries and run everything..or, worst case at one point, I need to add a third 7.2V...
·· There should be no reason to add a third battery.· At 3000mAh, the 7.2V batteries are actually overkill for the camera.· One bonus you'll get is that as the Hex Crawler starts to wear down the one 7.2V battery, you can actually swap the batteries and get a bunch more use out of them, since the camera will still have quite a bit of power (More than it needs) and the Servos will draw from the fresher of the two 7.2V batteries.
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Chris Savage
Parallax Tech Support
csavage@parallax.com