PDA

View Full Version : Yaw Rate Sensor


gburlison
01-11-2004, 09:13 PM
Looking at the Kit of parts, I do not see a yaw rate sensor this year. Is this correct?

KenWittlief
01-11-2004, 11:23 PM
you can buy yaw rate sensors from one of the electrical suppliers though - they are not too expensive.

bobtheblob
01-12-2004, 12:21 AM
Why are things so expensive on newarkinone.com? The Angular rate sensors sold on that site all exceed 150 dollars. I even saw some pushbutton switches for 20 dollars each.
Maybe I'm mistaken about the price, but that is ridiculous.

Anthony Kesich
01-12-2004, 12:38 AM
the manual was slightly decieving. It gave the wiring for a yaw rate sensor, but it wasn't on the parts list. Here's to FIRST recycling its manuals!

-Kesich

Adam Krajewski
01-13-2004, 05:41 PM
Why are things so expensive on newarkinone.com? The Angular rate sensors sold on that site all exceed 150 dollars. I even saw some pushbutton switches for 20 dollars each.
Maybe I'm mistaken about the price, but that is ridiculous.

Newark is expensive, but they have everything. Just the nature of the beast, I suppose.

To compare prices between different distributors, try http://www.findchips.com/. It is an EE's bestfriend.

Joe Johnson
01-13-2004, 10:35 PM
Why are things so expensive on newarkinone.com? The Angular rate sensors sold on that site all exceed 150 dollars. I even saw some pushbutton switches for 20 dollars each.
Maybe I'm mistaken about the price, but that is ridiculous.Future electronics sells an Analog Devices angular rate chip. Search the fori for ADXRS300 & ADXRS150.

Others have used these with good success.

Joe J.


P.S.
My mind had them at $30 or so, but looking on the Future website they are more like $50 (and that is in a "tray" where you may have to buy 20 - ouch!). The ones pre-mounted on a PCB are almost $100. Pretty tough to use them at that price!

I KNOW Newark has them in my catalog, but I can't find them on their website (man their part number search could use some cleverness built into it -- dumb as a post, it is). If I find it in a old catalog and they sell it to me at that listed price, do you suppose I could still use it legally? -- I suppose not. Why does FIRST even HAVE that $200 electronic limit? Why not have a limit on what you can spend on bushings? It makes about as much sense.

Looks like Digi-key has the chips too. $50 is the going rate for the sensor in a surface mount package. I hope I can afford one or two.

Skabana159
01-13-2004, 11:12 PM
Why does FIRST even HAVE that $200 electronic limit? Why not have a limit on what you can spend on bushings? It makes about as much sense.

It makes sense, because they do not want you to have a complex component that will give you a terrible advantage. Why not buy another IFI controller? You could double your PWM outputs and inputs.

A $300 bushing is not going to give you a ridiculous advantage, or at least in the scope that a $300 electronic component might.

Plus, there is a limit on bushings--- $3500.

FotoPlasma
01-13-2004, 11:20 PM
Why not buy another IFI controller? You could double your PWM outputs and inputs.
I don't want to get into a philosophical debate about the custom circuit spending limit, but it wouldn't technically be legal to do what you suggest. The rules state that a custom circuit may not directly generate the PWM signals for the motor controllers.

WizardOfAz
01-14-2004, 01:27 AM
Looking at the Kit of parts, I do not see a yaw rate sensor this year. Is this correct?

I bet there are lots of teams that have one from last year and never used it. Maybe you can make a deal.

ttedrow
01-14-2004, 02:53 PM
Go to the manufactures web site and see if they will send you an engineering sample for free. A lot of companys have this service. This may keep your spare parts cost down.



Tim Tedrow

Joe Johnson
01-14-2004, 05:16 PM
The cost accounting rules in the kit require that you account for the catalog value of the parts even if you had them donated.


<R61> A FIRST robot may be built using only

Items provided in the FIRST supplied Kit of Parts (or their exact replacement part)
Allowed Additional Parts and Materials as defined in this section in quantities consistent with the Cost Accounting requirements



<R71> Additional electronic components for use on the robot must be currently available from Newark InOne (http://www.newarkinone.com (http://www.newarkinone.com/)), Future Active(http://www.future-active.com (http://www.future-active.com/)) or Digi-Key Corporation(http://www.digikey.com (http://www.digikey.com/)). The total catalogue value of dditional electronic components must not exceed $200.00 USD. This cost is counted as part of the $ 3,500 limit. No single electronic component shall have a catalog value of over $100.00 USD.


Note the references to "currently available" & "total catalogue value." How you actually obtained something is immaterial.

The way I read the rules, they have to be in the current catalogs and you have to meet the cost accounting limits with the listed prices.

Joe J.

Matt Krass
01-14-2004, 05:37 PM
Can we use the gyro from our previous year robot? It's just sitting on there looking pretty after all.

rishi224
01-14-2004, 08:39 PM
Future electronics sells an Analog Devices angular rate chip. Search the fori for ADXRS300 & ADXRS150.

Others have used these with good success.

Joe J.


P.S.
My mind had them at $30 or so, but looking on the Future website they are more like $50 (and that is in a "tray" where you may have to buy 20 - ouch!). The ones pre-mounted on a PCB are almost $100. Pretty tough to use them at that price!

I KNOW Newark has them in my catalog, but I can't find them on their website (man their part number search could use some cleverness built into it -- dumb as a post, it is). If I find it in a old catalog and they sell it to me at that listed price, do you suppose I could still use it legally? -- I suppose not. Why does FIRST even HAVE that $200 electronic limit? Why not have a limit on what you can spend on bushings? It makes about as much sense.

Looks like Digi-key has the chips too. $50 is the going rate for the sensor in a surface mount package. I hope I can afford one or two.

:confused:

the ones u wrote about r just chips. how do u plan to put them up on the robot??
if u have any info plz post it.

FotoPlasma
01-14-2004, 09:55 PM
:confused:

the ones u wrote about r just chips. how do u plan to put them up on the robot??
if u have any info plz post it.
FIRST nicely provided us with a big chunk of protoboard. The chips to which Dr. Johnson referred come in either BGA (ball grid array, terrible for us) or DIP (dual inline pin, very good for us) packages. I assume he plans to put them in some sort of enclosure and attach them to the robot using any of a number of available methods (nuts and bolts, epoxy, zip ties, it doesn't really matter).

Caleb Fulton
01-15-2004, 12:47 AM
Can we use the gyro from our previous year robot? It's just sitting on there looking pretty after all.


Yes, you should be able to, as the gyro's output is just an analog voltage between 0 and 5v.

Joe Johnson
01-15-2004, 03:56 PM
Yes, you should be able to, as the gyro's output is just an analog voltage between 0 and 5v.
While you can easily hook them up to your CPU, as I read the rules they are illegal.

Joe J.

rishi224
01-15-2004, 06:33 PM
FIRST nicely provided us with a big chunk of protoboard. The chips to which Dr. Johnson referred come in either BGA (ball grid array, terrible for us) or DIP (dual inline pin, very good for us) packages. I assume he plans to put them in some sort of enclosure and attach them to the robot using any of a number of available methods (nuts and bolts, epoxy, zip ties, it doesn't really matter).

i searched again.........
i didnt find any chips in DIP...........
could u please tell me where i could find the chips in DIP all i found was BGA :(

it would be really helpful if u could tell me where i could get one in DIP

thanks ^_^

FotoPlasma
01-15-2004, 07:20 PM
i searched again.........
i didnt find any chips in DIP...........
could u please tell me where i could find the chips in DIP all i found was BGA :(

it would be really helpful if u could tell me where i could get one in DIP

thanks ^_^
http://www1.future-active.com/Comergent/en/US/adirect/future?cmd=search&domSendTo=byID&domProductQueryName=ADXRS300
http://www1.future-active.com/Comergent/en/US/adirect/future?cmd=search&domSendTo=byID&domProductQueryName=ADXRS150

As far as I know, the ADXRS[150/300]EB are DIPs. Hmm, they aren't cheap... :(

rishi224
01-15-2004, 07:28 PM
http://www1.future-active.com/Comergent/en/US/adirect/future?cmd=search&domSendTo=byID&domProductQueryName=ADXRS300
http://www1.future-active.com/Comergent/en/US/adirect/future?cmd=search&domSendTo=byID&domProductQueryName=ADXRS150

As far as I know, the ADXRS[150/300]EB are DIPs. Hmm, they aren't cheap... :(

i cheked them out!

they arnt DIP
http://www.analog.com/Analog_Root/productPage/productHome/0%2C2121%2CADXRS300%2C00.html

at the end bottom of the page it says that its grid array :(

i really don know how to use grid array and dont have the time either. am in a fix:(

thanks for ur help. plz tell me as soon as u find any thing

jjv
01-20-2004, 01:33 PM
Does anyone have specs on last years gyro?
or know the maker/model of it?

Thanks!

Greg Ross
01-20-2004, 02:30 PM
My reading of the rules agrees with yours, Dr. Joe. But FIRST, today, said they ARE allowed:Section: 5.2.6 Status: Answered Date Answered: 1/20/2004
Q: Are we allowed to use gyros that were given by F.I.R.S.T. last year?

A: Yes.

WizardOfAz
01-20-2004, 02:54 PM
My reading of the rules agrees with yours, Dr. Joe. But FIRST, today, said they ARE allowed:

Yes, this seemed to me to be an odd answer to that question.
Is that part still available?
Is is available from one of the preferred suppliers?
Does it cost < $100?

If any of the above questions are answered "no" (and it looks to me like they are all "no"), then where does FIRST's answer to that question leave rookie teams?

Over the weekend I tried to submit clear questions that should resolve some of the discussions we've been seeing about what parts have to be in the $100/$200 limit, and in what cases the preferred suppliers have to offer the part. No response to those yet though.

Bill

jjv
01-20-2004, 05:39 PM
The -EB model is their Evaluation Board model, they have the same BGA chip premounted on a 20 pin dip board to make it easier to use.
Since technically, all it is is a pcb (which don't count towards price limits) and 7.2cents worth of caps, would we be able to use the price for the BGA?

KenWittlief
01-21-2004, 09:08 AM
FIRST says we can use last years yaw rate sensor

______________________
Yes, this seemed to me to be an odd answer to that question.
Is that part still available?
Is is available from one of the preferred suppliers?
______________________

from team update 3, it sounds like they are saying, if you can get a part from one of the catalogs, then you can use a similar part, even if you actually obtain it from somewhere else.

I take this to mean, you can get yaw rate sensors from the catalogs, and the one FIRST gave us last year is "similar enough" that they will allow us to use it.

but you still have to account for its cost as an electrical component.