Due to the well-founded frustration of people asking questions about constantly answered problems, I'd like to dedicate this thread for common answers to common questions. For example, I'd answer a common question like this:
Blah blah blah helpful guidance on DR4Bs blah blah blah...
post a couple of helpful links and whatnot
Make sure when you answer a question to put the related topic in bold, and keep the answer tidy.
DO NOT ANSWER THE SAME QUESTION TWICE UNLESS THE FIRST ANSWER IS COMPLETELY WRONG
Also, not chit chat or quoting people. This is meant to be a clean-looking thread where new teams could scroll down the page to find the answer that they need.
Some ones we need first:
Lift help (DR4Bs, Scissor lifts, and chain bars)
Please keep this an active thread full of useful information!
Question: How do I copy team whoever’s robot?
Answer: You don’t. That team put their reveal on youtube to share their ideas, not to allow other people to copy them screw for screw. However, if you see a subsystem you would like to replicate, you can definitely draw inspiration from it. Just try to copy that subsystem at the beginning, and then make modifications to it based on problems that arise. (If the subsystem is out of the size limit, make it smaller, etc.)
Let's Make a PID Loop Episode 1 -- Basic Setup
Question: What are the standard gear ratios for usual subsystems?
Answer: This will largely depend on your number of motors, friction, and battery voltage. However, below is my estimate for the fastest reasonable amount you can gear up each standard subsytem for this year’s game.
Drive: 1:1 torque with 4” wheels.
Lift: 1:5 speed (varies for elevator lifts and very small, light lifts)
Chain bar: 1:5 turbo
Swing arm: 1:3 turbo
Side rollers: 1:1 turbo with 12 tooth sprocket
Drive: 1:1 speed with 4” wheels or 1:1 turbo with 3.25” wheels
Lift: 1:5 turbo (varies for elevator lifts and very small, light lifts)
Chain bar: 1:3 turbo
Claw: you shouldn’t be putting more than 1 or 2 motors on your claw :)
Swing arm: 1:1 torque
Side rollers: you should only use 2 motors on side rollers
Drive: 1:1 Turbo with 4” wheels or 3:1 torque with 3.25” wheels
Question: Why are my motors jittering?
Answer: Your motors may be stalling or causing the cortex to stall. The motors have a heat sensor to prevent safety hazards, so any activity that causes the motors to noticeably heat up will cause them to stall. To prevent stalling, add motors, decrease the gear ratio, or decrease the friction. Similarly, the cortex has a sensor on ports 1-5 and another on ports 6-10 to prevent too much power from being pulled. If your 4 drive motors are coming from ports 1-4 and your drive is stalling, try spreading out the ports to 1-2 and 9-10 to prevent this type of stalling.
Question: What is a good parts list for a beginning team?
Answer: The following list is one I created to help out my school’s teams. This is NOT the only parts list or correct parts list, but I think it is a good one. It will give you enough parts to build a basic robot with a small cushion of extra parts in case you run out of something, and it costs around $2000.
VEX Robotics Parts Wish List for 2017-2018 Season for 1 New Team
Part Name Number Cost per Part
1 VEX Bumper Switch (2-pack) 276-2159 $12.99
1 VEX Potentiometer (2-pack) 276-2216 $12.99
1 VEX Yaw Rate Gyroscope Sensor 276-2333 $39.99
1 VEX LCD Display 276-2273 $49.99
3 VEX 3-Wire Extension Cable 6" (4-pack) 276-1427 $4.99
12 VEX 2-Wire Motor 393 with Motor Controller 29 276-1668 $24.98
3 VEX Shaft Collar (16-pack) 276-2010 $7.99
1 VEX High Strength 84-Tooth Gear (4-Pack) 276-3438 $12.99
2 VEX 4" Omni-Directional Wheel (2-pack) 276-2185 $24.99
1 VEX Star Drive Coupler 8-32 x 0.500" (25-pack) 276-4989 $1.99
1 VEX Aluminum C-Channel 1x3x1x35 (2-pack) 276-4359 $15.99
5 VEX Aluminum Bar 1x25 (16-pack) 276-2307 $29.99
1 VEX Aluminum C-Channel 1x5x1x25 (6-pack) 276-2290 $39.99
6 VEX Aluminum C-Channel 1x2x1x35 (6-pack) 276-2289 $34.99
1 VEX Hinge (2-pack) 275-1272 $9.99
6 VEX 7.2V Robot Battery NiMH 3000mAh 276-1491 $29.99
1 VEX Battery Clip (4-pack) 276-4042 $4.99
4 VEX Smart Charger v2 with Power Cord 276-2519 $18.98
1 VEXnet Backup Battery Holder 276-2243 $9.99
3 VEX High Strength Gear Kit 276-2250 $18.99
1 VEX Gear Kit 276-2169 $12.99
1 VEX Washer, Steel (200-pack) 275-1024 $4.95
2 VEX Washer, Teflon (25-pack) 275-1025 $4.95
2 VEX Drive Shaft Bar Lock (8-pack) 275-1065 $6.45
7 VEX Bearing Flat (10-pack) 276-1209 $4.99
3 VEX Additional High Strength Chain 276-2172 $24.99
1 Star Drive Screw 8-32 x 2.000" (50-pack) 276-5004 $4.99
1 Star Drive Screw 8-32 x 1.750" (50-pack) 276-4999 $5.99
1 Star Drive Screw 8-32 x 1.500" (50-pack) 276-4998 $4.99
1 Star Drive Screw 8-32 x 1.250" (50-pack) 276-4997 $4.99
1 Star Drive Screw 8-32 x 1.000" (100-pack) 276-4996 $6.99
1 Star Drive Screw 8-32 x 0.875" (100-pack) 276-4995 $6.99
1 Star Drive Screw 8-32 x 0.750" (100-pack) 276-4994 $5.99
1 Star Drive Screw 8-32 x 0.625" (100-pack) 276-4993 $5.99
1 Star Drive Screw 8-32 x 0.500" (100-pack) 276-4992 $4.99
1 Star Drive Screw 8-32 x 0.375" (100-pack) 276-4991 $4.99
2 Star Drive Screw 8-32 x 0.2
2 VEX High Strength Sprocket 18 Tooth (4-Pack) 276-3878 $12.99
2 VEX High Strength Sprocket 24 Tooth (4-Pack) 276-3879 $12.99
5 VEX Pillow Block Bearing & Lock Bar Pack 276-2016 $7.99
1 VEX Battery Extension Cable 276-3442 $4.99
15 VEX Nylon Spacer Variety Pack 275-1066 $4.95
**Note: each price is the cost of 1 set. I VEX Nylon Spacer Variety Pack, not 15, costs $4.95.
Question: I need design ideas.
Answer: Youtube has a huge array of matches and reveals posted. The best match I personally have seen (on youtube or in person) I’ve linked below, but better matches will occur as the season goes on, and it’s only a matter of time before these designs are obsolete.
Look for good concepts, clever ideas, and good strategies. If you can combine them successfully, you will have a very strong robot.
ROBOCOM VEX IN THE ZONE
I hope this post will help to answer some of the basic questions newer members have. @Mira, if you could submit this as the answer to the original question, it would make this information more accessible and hopefully help some of you newer builders and programmers get started. Best of luck to everyone this season, and thank you for reading!
lol ok thats it sorry its so crazy long but pls post it i appreciate it
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