Forum: FIRST Tech Challenge
11-09-2006, 23:32
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Replies: 9
Views: 2,077
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Forum: FIRST Tech Challenge
22-08-2006, 14:19
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Replies: 4
Views: 904
Re: Reading an encoder with interrupts
the timer is used to determine the amount of time between encoder interrupts so you can determine the speed at which your bot is progressing.
the timer interrupt occurs when the timer overflows, so...
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Forum: FIRST Tech Challenge
18-06-2006, 23:53
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Replies: 29
Views: 3,534
Re: Adding Bluetooth to Vex
there's also a microcontroller on the programming dongle. don't know that anyone has actually watched the traffic between ifiloader and the programmer or if anyone has tried looking at the debug...
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Forum: FIRST Tech Challenge
14-06-2006, 23:14
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Replies: 12
Views: 2,934
Re: VEX Start Kit Projects
this is not a good idea. since multiplication is kind of expensive, computationally speaking go with...
left_drive = (ultrasonic_value > 40) ? 85 : 127;
... which, for anyone unfamiliar with the...
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Forum: FIRST Tech Challenge
06-06-2006, 21:05
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Replies: 17
Views: 4,242
Re: Attaching the CMUcam to the Vex controller
is there a reason to not just use the programming cable? sure you've got to kludge a connector, but you've already blown $100 for an extra fancy level shifter, or did ifi obfuscate the functionality...
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Forum: FIRST Tech Challenge
01-06-2006, 08:19
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Replies: 10
Views: 2,952
Re: Vex Library and Sample Code
i'm guessing that rx is receiver 1 or 2 and that channel is 1 through 6. since there's no way to return an error indication, if we get rx 10, channel 9, we'll just return the first channel from the...
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Forum: FIRST Tech Challenge
31-05-2006, 08:25
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Replies: 10
Views: 2,952
Re: Vex Library and Sample Code
arrrgh, you wouldn't believe the long insightful answer i had for you when my connection timed out...
the short answer is study the sample code and refer to the 18f8520 datasheet, (watch any ad for...
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Forum: FIRST Tech Challenge
29-05-2006, 22:50
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Replies: 10
Views: 2,952
Re: Vex Library and Sample Code
oops. sorry, thought you were maybe talking about some existing easyC code about which i know nothing.
to test for a limit switch closed on pin 1 in the analog/digital section of the rc and then...
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Forum: FIRST Tech Challenge
29-05-2006, 16:53
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Replies: 10
Views: 2,952
Re: Vex Library and Sample Code
well, gee, if you're not going to read your inputs and check your outputs it doesn't seem like there's much left for you to do.
if you just want to hide implementation details you can always use...
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Forum: FIRST Tech Challenge
28-05-2006, 15:55
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Replies: 67
Views: 6,976
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Forum: FIRST Tech Challenge
24-05-2006, 08:32
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Replies: 1
Views: 1,265
Re: Interupts on Vex in MPLab
what interrupt did you want to use? timer0 is used already. the guys at vexlabs suggest not using them at all to avoid glitches in the pwm and the communications with the master controller. but,...
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Forum: FIRST Tech Challenge
15-05-2006, 08:12
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Replies: 6
Views: 1,584
Re: Homemade parts
pins 2, 3 and 4 of the motor section are brought out from three of the hardware pwm pins on the 18f8520 and can e programmed to generate pwm signals at frequencies and duty cycles other than those...
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Forum: FIRST Tech Challenge
30-04-2006, 20:25
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Replies: 1
Views: 917
Re: Ultrasonic Distances
the ultrasonic sensor does not return an analog value. it returns the time it takes sound to make a round trip out from the sensor to whatever's out there and back to the sensor. the distance can...
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Forum: FIRST Tech Challenge
30-04-2006, 20:12
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Replies: 27
Views: 10,453
Re: Programming Vex w/ MPLab
looks like your project is set up to use easyc. if you're not going to use easyc i'd guees that you need to select c18. i'm am not currently at my accursed windows machine, but i believe this is...
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Forum: FIRST Tech Challenge
17-04-2006, 15:55
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Replies: 14
Views: 1,683
Re: 6WD?
you've got signal next to the labels, (white wire), 7.6v in the middle, (orange wire), and ground out at the edge, (black wire). use jameco 157382CK 3 pin housing with 157382CK female pins and...
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Forum: FIRST Tech Challenge
16-04-2006, 18:21
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Replies: 14
Views: 1,683
Re: 6WD?
so, how about you just share signal and ground, but pull power off of one of the free motor ports.
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Forum: FIRST Tech Challenge
14-04-2006, 21:09
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Replies: 14
Views: 1,683
Re: 6WD?
if you can find a radio shack that still has one, you can probably pick up a programming kit for $50. failing that how about making up a pwm y cable to feed the signal from a single port to two...
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Forum: FIRST Tech Challenge
09-04-2006, 11:01
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Replies: 8
Views: 1,240
Re: Mounting encoder/cutting 12 in axel
i was just wondering if anyone had tried converting one of the encoders to quadrature? either adding another slot type sensor or maybe printing out a disk and sticking it on the disk in the encoder...
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Forum: FIRST Tech Challenge
22-03-2006, 20:23
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Replies: 4
Views: 1,223
Re: VEX + Coprocessor?
you've got two uarts available, the programming port and the rx and tx pins next to a/d port 16. on the programming port the leftmost pin is tx, next to it is rx and next to that is ground. of...
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Forum: FIRST Tech Challenge
15-01-2006, 12:19
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Replies: 4
Views: 1,305
Re: bending parts
i am concerned that the bends are at right angles and at the right locations so that the holes align when it comes time to close the piece with the gusset. do you think it would help if i screwed a...
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Forum: FIRST Tech Challenge
14-01-2006, 21:04
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Replies: 4
Views: 1,305
bending parts
i need to bend one of the 1x25 bars into something nearly square. i mean with 4 four right angles and a gap i intend to close with one of the cross gussets. i'm probably also going to need to bend...
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Forum: Programming
27-12-2005, 19:20
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Replies: 14
Views: 8,823
Re: VEX programming
uh, yeah. i got the prototype programmer last summer, so i don't even have easyc 1.1. got mcc18 instead. what ifi told me was that if i want easyc i should buy a second programmer.
oops, i'm...
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Forum: FIRST Tech Challenge
27-12-2005, 15:13
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Replies: 4
Views: 1,599
Re: $200 vex starter kit
nothing on the website indicates that it is not on sale in stores. here (http://rsk.imageg.net/graphics/coupon/r2169490_rebatecoupon.pdf) is the link to the rebate form.
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Forum: FIRST Tech Challenge
26-12-2005, 22:45
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Replies: 2
Views: 1,029
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Forum: General Forum
26-12-2005, 12:26
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Replies: 17
Views: 1,915
Re: VEX The Next Level
'til the end of december the buy in is $200 plus. rat shack has the starter kit on sale for $250 with a $50 rebate and free shipping. of course, if you pick one up at your local 'shack, you don't...
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