[FTC]: New Tetrix Parts

[Andrew Remmers]

Thought I would share this if anyone wasn;t aware.

Today the new parts in the Tetrix kit were released.

New parts consist of:

Continuous Rotation Servo
Tread Rubber Inserts
Tread Conveyor
Tread Idler Wheels
Tread Sprocket
Tread Links
Tread Kits
4" Omni-Wheels
Tread Accessory Pack (which I am having trouble figuring out what is in this "pack")

The link is below

http://parts.ftcrobots.com/Default.aspx?bhcp=1

Hope this helps

Andrew

[Tony Allen]

The Tread Accessory pack will consist of paddel's for turning your tread system into a conveyor and rubber inserts for the treads. Also a new thermal protected DC Motor power cable will be an added as a new part.

[iblis432]

I noticed that the continuous rotation servo does not have position feedback. Am I correct in understanding this means that I can only tell the servo to go forward or backward and not to go to a specific point? Or am I misunderstanding what this means.

[Aren Siekmeier]

Originally Posted by iblis432

I noticed that the continuous rotation servo does not have position feedback. Am I correct in understanding this means that I can only tell the servo to go forward or backward and not to go to a specific point? Or am I misunderstanding what this means.

Seems that it's not much of a servo without position feedback.... I don't know...

[EricVanWyk]

Originally Posted by iblis432

I noticed that the continuous rotation servo does not have position feedback. Am I correct in understanding this means that I can only tell the servo to go forward or backward and not to go to a specific point? Or am I misunderstanding what this means.

Your understanding matches mine.

We did this to a couple position servos when I was in highschool. Basically, you break the internal feedback loop and remove the hard stops and it turns into something that approximates a normal motor.

I agree that it likely doesn't deserve the "servo" moniker at this point: It looks like a servo, talks like a servo, but doesn't quack like one. Not sure what I would call it. "Motor with integrated control electronics" doesn't sound as sexy as "continuous rotation servo"

[biojae]

Originally Posted by EricVanWyk

Your understanding matches mine.

We did this to a couple position servos when I was in highschool. Basically, you break the internal feedback loop and remove the hard stops and it turns into something that approximates a normal motor.

I agree that it likely doesn't deserve the "servo" moniker at this point: It looks like a servo, talks like a servo, but doesn't quack like one. Not sure what I would call it. "Motor with integrated control electronics" doesn't sound as sexy as "continuous rotation servo"

I tend to call them miniature speed controllable geared motors.
(At least the parallax ones are speed controllable, I have no idea about these ones)

[PhilBot]

Originally Posted by biojae

I tend to call them miniature speed controllable geared motors.

The speed control on a "hacked" servo is crude at best. Most really ARE just a gear reduced motor in an easilly mountable container.

It depends on whether they just removed the mechanical stops/feedback, or changed the drive circuit

What IS certain is that there is no position feedback.

Phil.

[biojae]

Originally Posted by PhilBot

The speed control on a "hacked" servo is crude at best. Most really ARE just a gear reduced motor in an easily mountable container.

It depends on whether they just removed the mechanical stops/feedback, or changed the drive circuit

What IS certain is that there is no position feedback.

Phil.

I have only dealt with the parallax continuous rotation servos, those are speed controllable.

It would be nice if these ones could be speed controlled.

[Chris is me]

This is not a facetious question; I know of an FTC team that's actually looking for the answer to this.

Are the new tank treads close enough to the Vex tank treads in size, shape, etc. that they can use the Vex tank tread links in their place? I think the rules permit "duplicates" like that. They're looking to save a little bit of cash for a particular feature and want to only buy the sprockets, and they look similar enough that I figure it's worth asking, but since I / they don't have any new tread material in hand they can't really compare the two.

[Andrew Remmers]

Sadly the rule with using VEX parts in FTC was removed last year. Using VEX tread would be illegal even if they had the same size link.

"g. Vex parts of any type are not allowed."

Sorry for the bad news on that aspect.

But what they could do is look for a sponsor or something to donate some money. We got $1800 donated from things that were in our build space for FRC.
I agree that FTC parts are a little on the expensive side, which is why our team tries to avoid modifying them at all cost.

Andrew

[Chris is me]

That's a bit disappointing. I thought I read a rule about "identical replacement parts" or something, but after a second read through I can't find it. There goes $70...

[gblake]

Originally Posted by PhilBot

...What IS certain is that there is no position feedback.

OK - I'll ask... Can anyone tell me why they would call this gizmo a "Servo" instead of calling it a motor? Maybe to pander to some RC enthusiasts that call any motor (except the main drive motor for a vehicle) a Servo? I'm confused.

Originally Posted by Joyride_67_1902

Sadly the rule with using VEX parts in FTC was removed last year. Using VEX tread would be illegal even if they had the same size link....

Do the currrent rules allow replacement parts of any sort?

Blake

[biojae]

Originally Posted by TETRIX® Continuous Rotation Servo

Featuring fully proportional forward and reverse speed control

http://parts.ftcrobots.com/store/det...01&c=0&t=0&l=0

It appears that the FTC continuous rotation "Servos" are speed controllable.

[Andrew Remmers]

Originally Posted by Chris is me

That's a bit disappointing. I thought I read a rule about "identical replacement parts" or something, but after a second read through I can't find it. There goes $70...

If we could use identical parts I'd think we would just buy gear stock instead of gears from Tetrix. We however can use identical hardware from anywhere in any length which will come in handy im sure.

[Andrew Remmers]

Originally Posted by gblake

Do the currrent rules allow replacement parts of any sort?

I'm guess I'm having a hard time interpreting what you mean by replacement.

Do you mean like a spare part in tetrix kit, or something that does the same thing even looks the same from out of kit?