Backup Battery

[Tottanka]

Does anybody know waht the backup battery is used for this year?

[jgannon]

I would assume that it is being used to keep the RC from turning off when the main voltage momentarily spikes low.

[Tomasz Bania]

Originally Posted by jgannon

I would assume that it is being used to keep the RC from turning off when the main voltage momentarily spikes low.

I second that answer.

[RyanN]

Note: I have not read through all the rules. It could be used for a servo if someone wanted to use one. Mostly for retaining a connection of the main battery has a bad connection.

[gallo26]

From what my software team has told me, the backup battery powers servos for the camera, the camera, and sensors plugged into the RC board. so you dont need it, but then again, sensors would be nice. haha

[Pavan Dave]

Originally Posted by gallo26

From what my software team has told me, the backup battery powers servos for the camera, the camera, and sensors plugged into the RC board. so you dont need it, but then again, sensors would be nice. haha

Use it for servos (shifting etc.) and sensors as being able to keep your robot running for a few seconds just in case something happens during game play. Unfortunately there is no camera needed this year but you still have a servo or two if you want to shift so there is still some use for it...

[Tomasz Bania]

Side Question: Are we allowed to use the camera's this year? (Heard or read something about the fact that 2 of the trackballs have 12" circular spots on them for visual detection, so I'm thinking it's allowed. Just looking for a clarification.

Tomasz Bania

[Ricky Q.]

Originally Posted by Tomasz Bania

Side Question: Are we allowed to use the camera's this year? (Heard or read something about the fact that 2 of the trackballs have 12" circular spots on them for visual detection, so I'm thinking it's allowed. Just looking for a clarification.

Tomasz Bania

Check the flowchart, it is COTS and under the $400 from IFI, so it appears the answer would be yes.

Go nuts.

[RyanN]

I do NOT think you can use the camera this year as of rule R36.

<R36> COTS ITEMS from ROBOTS entered in previous FIRST competitions or COTS
MECHANISMS that are no longer commercially available may be used under the following
conditions:
• The item must be unmodified, and still in its original condition as delivered from the
VENDOR
• The item must not be a part custom made for the FIRST competition and provided in the
Kit Of Parts for a previous FIRST Robotics Competition (e.g. 2006 FRC transmissions,
custom-made motor couplers, custom sensor strips, 2006 IFI CMUcam II modules, etc.
are not permitted)
• The item must satisfy ALL of the rules associated with materials/parts use for the 2008
FIRST Robotics Competition)

Please correct me if I'm wrong, because I would love to use the camera this year for autonomous.

[Tomasz Bania]

Originally Posted by RyanN

I do NOT think you can use the camera this year as of rule R36.



Please correct me if I'm wrong, because I would love to use the camera this year for autonomous.

It does not mention anything about the 2007 cameras!

EDIT: Still a custom part, but weird why they specify 2006.

I know I heard or read something about the fact that 2 of the balls have those 12" circles to assist A vision system during the hybrid period. I guess we should start developing our own camera systems!

[BQuennell]

Also on the backup battery, I'm curious to if we can use a backup battery charging circuit from last year. It doesnt list any design in the manual and rule R49 lists
When mounted on the ROBOT, the backup battery may be charged from the 12VDC primary battery by using the custom charging circuit available from Innovation First Inc. or any similar charging circuit (note: IFI will provide the design for this circuit on the IFI website, however teams must obtain the parts for this circuit and assemble it themselves). The use of this circuit is strongly encouraged.

With that does that mean teams can design their own circuit as well?

[keen101]

Originally Posted by BQuennell

Also on the backup battery, I'm curious to if we can use a backup battery charging circuit from last year. It doesnt list any design in the manual and rule R49 lists
When mounted on the ROBOT, the backup battery may be charged from the 12VDC primary battery by using the custom charging circuit available from Innovation First Inc. or any similar charging circuit (note: IFI will provide the design for this circuit on the IFI website, however teams must obtain the parts for this circuit and assemble it themselves). The use of this circuit is strongly encouraged.

With that does that mean teams can design their own circuit as well?

It is my understanding that a backup battery charging circuit is recommended. I also take it that you can design your own. The one from IFI is not supported, and is there as a guideline/sample. You basically are taking your own risks.

I was seriously thinking about building a charging circuit for it last year. But, it turned out for some reason we didn't need it. I guess out of luck I actually got them to charge well.

[Andy A.]

The backup battery serves to power the RC during 'brown outs' and as positive voltage on the middle pin of PWM outputs. Effectively this means that it powers servos and saves you from your robot shutting down and resetting under heavy loads and low batteries. In the past we would have loved to have this kind of backup..

The charging circuit published by IFI in the past isn't all that great. Unless your robot is using a great number of servos or sensors powered by a PWM output it probably isn't nessecary to include the backup charging circuit. Simply charging the battery off the robot every few matches is perfectly adequate.

It is however required to include the backup battery on the robot and connected to the RC. The included battery pack is fine, but it is acceptable to replace it with any 7.2v battery pack (these are common in R/C cars, and you can get very high capacity packs if you so desire).

-Andy A.

[PhilBot]

Team 1629 designed and built an on-board charger circuit for 2007. It was based on the "Improved" charger design that was released late in the build season (the one that showed the extra battery terminal that was required).

The schematic and PCB were designed with the free software from ExpressPCB.com.

The board is larger than it needs to be (2.5x3.8) but this is their economic "Mini-pcb" size. By keeping to this size you can get 3 pcb's made in 3 days for less than $60. Build one for real, one for a spare and give one away

I've attached a zip to this message. It includes a pdf of the schematic and PCB as well as the actual ExpressPCB files. So you can go to ExpressPCB.com, download the software, open the PCB design file and then "Order Online".

It was great not having to remember to remove the battery to keep it charged.

This circuit also has pads for including a blocking diode so that the backup battery cannot back-power the RC. This was not included in the "official" schematic" so if you want to play by the letter of the law, just insert a wire in place of D3.

Also note that R1 and R4 dissipate power (get hot), so make sure you use at least 2W resistors.

Phil.

[Laaba 80]

Originally Posted by Tomasz Bania

I know I heard or read something about the fact that 2 of the balls have those 12" circles to assist A vision system during the hybrid period. I guess we should start developing our own camera systems!

I dont think it said a vision SYSTEM, I thought it just said to help vision. I think it will help the referees keep track of which ball is which. This game is going to be complicated for them, they need all the help they can get.
Joey