Re: 2015 Beta Testing - The Components are Here.
 

I think it would be more accurate to say say "once you add an active power supply to PWM signals from the MXP ..."

This does not keep you from supplying 3.3v or 5v from the MXP header or battery voltage from the PDP to the DIO pins, It only keeps you from adding a power supply to add a different voltage.

No matter what board you use, if you claim that it is passive, you'll have to prove it at inspection. Not sure how having a prototyping area changes that. An active circuit added to a prototyping area of an otherwise passive board makes it active.

Re: 2015 Beta Testing - The Components are Here.
 

I wanted to share with you the reason I am asking about the PWM voltages. A few of the kids and I are designing a "PWM Extender" which will attach to the robot and inline with the PWM cable. The "PWM Extender" will be 2.5" x 1.5" PCB with a row of 8 LEDS to indicate the servo (or motor) command. This will allow our team to monitor (or debug) the robot health from in the stands. The "PWM Extender" is parasitic in that it will steal from the 6V supply (middle conductor) to power a ATMEGA88 uController to drive the LEDs as a function of the signal command. There is a 5V voltage regulator.

Our team would like to place as many indicators on the robot so the driver and operator do not have to look down at the laptop. We have noticed that no one ever looks down during the competition.

Yes, it is active but only for the LEDs. We would be glad to share the design, gerber files, uController code, etc with anyone who wants it. But, I have a feeling that most will reject it.

Your thoughts?

Re: 2015 Beta Testing - The Components are Here.
 

From the reply on the FIRST forums, I read that to mean that once any components at all (power or otherwise) are added to the board, and the board is no longer simply a breakout, it is an active board.

Re: 2015 Beta Testing - The Components are Here.
 

This is definetly active. In addition this would be illegal in any previous year, as a motor controller is not allowed to connect to a custom circuit. It would be legal for you to make a seperate board and have the roboRIO communicate the values it's sending to the motor controllers to the seperate board over another communication method (I2C, SPI, CAN, serial, ethernet, etc).

Given how hard it is to see items on the robot during a match, a better option might be to have either the roboRIO log the data you want to it's internal flash or send the data to the dashboard. Both the LabVIEW dashboard and the SFX dashboard support logging by default.

Re: 2015 Beta Testing - The Components are Here.
 

Are you interpreting the 4 examples of items that are ok for a passive device as the only 4 items allowed? The definition allows many more things.

Re: 2015 Beta Testing - The Components are Here.
 

Joe, I like your first suggestion to use a serial message to another device (maybe a PCDuino) to display our commands on the robot. We can set a message buffer equal to the motor (and servo) commands then send it to the PCDuino maybe somewhere high for best 'line of sight'. This would also help us debug in the pit.

We do want to try placing the commands on the robot this year with indicators such as colored LEDs. In previous years, we have spent many hours reconfiguring the dashboard but we NEVER look down at it during competition. Even the coach is too busy to look down. This way the entire pit crew in the stands can follow the driver and operator commands to educate them on component failures. This might expedite getting the robot ready for the next match.

Re: 2015 Beta Testing - The Components are Here.
 

Has anyone seen the specs on the roborio accelerometer? I searched but could not find any information.

Re: 2015 Beta Testing - The Components are Here.
 

It's a 3 axis, selectable +/- 2g, 4g, or 8g. MMA8452Q

Re: 2015 Beta Testing - The Components are Here.
 

With today's clarification that plugging in an active component to a passive MXP makes the MXP active, I agree with you. But it sounds like they're trying to figure out a workaround.

Re: 2015 Beta Testing - The Components are Here.
 

I certainly hope they do - for everyone. That clarification makes the current preliminary rules much more broad that I had anticipated or understood them to be.

Re: 2015 Beta Testing - The Components are Here.
 

I have been reading many of these post and I have not understood the benefit of the mxp pcb. All I can see is that it is an exercise in relocating the connector from deep inside the 2x17 male connector. I have several expansion ideas but my thoughts are to connect directly to the 2x17 male connector. I am not seeing the benefit of the expansion board. Moreover, there are no active or passive issues. What am I missing?

Re: 2015 Beta Testing - The Components are Here.
 

That wiring the signal and ground of a 3 pin connector to the signal and ground mixed into the 34 pin connector is a pain. A huge pain if you want to use more than the number of ground pins available.

Re: 2015 Beta Testing - The Components are Here.
 

Yes and no. It allows you to have easy access to the pins in the MXP, and lay them out in a manner that is easy to use - such as providing ground pins and in a 3-pin arrangement so you can plug in a regular PWM cable. To relocate the connector we just need a cable. You then still have the issue of what you connect to it and how.

You could use a connector with a cable and solder the wires directly to things, for sure. It's just often more inconvenient to do so, depending on what exactly you're trying to do.

The benefit is 'ease of handling'. Given the current preliminary rules/rulings/statements (especially today's response on the forums), I'm not sure where just plugging something straight in (say, an encoder) through wire on a cable/connector would sit on the active/passive fence. But, they are working on it.

Re: 2015 Beta Testing - The Components are Here.
 

This is not at all surprising. Most resistors increase in resistance as the temperature goes up, like when they have a lot of current running through them. In addition to the reduction in the battery's reduced capability as reflected on the discharge curves, you are also losing more energy to heat in the wiring and the motors at high draw.

Re: 2015 Beta Testing - The Components are Here.
 

Hi Joe,

Do you think you have the DS log for this match that you could attach or send to me?

Thanks,
-Joe