Robot Radio 12V, Increased Brownout Risk?

FIRST General Forum
1

Not sure if this has been discussed on CD already, if so I apologize.
This year our new compact robot radio has a DC voltage rating of 12-18 V. Also, so far in my experience it takes up to twice as long to initialize as the former routers.

I analyzed the voltage levels from our 2015 matches and did notice several instances where we dropped below 10.5 volts during a match even with good batteries.
Has anyone experimented with the radio yet to see at what voltage the router would shut down/reboot, or if there are any symptoms of a reduced voltage during a match (reduced range, or maybe the router goes into a safe mode that reduces capability temporarily?).

I’m getting increasingly nervous that a powerful drive system we are designing will kill our radio during a match.

2

Power to the radio should be taken from the Cross the Road Electronics Voltage Regulator 12 V 2 A rail, Per R43, which will maintain voltage below what the RoboRio browns out at.

3

From what I understand, The VRM has a separate converter for the radio board and keeps the voltage steady at 12V even if the battery voltage drops significantly below 12 V

4

The radio is required to be plugged into a Voltage Regulator Module, which functions down to 5 volts per its specifications.

5

Yes of course, but I didn’t realize the VRM can maintain 12V if it’s input voltage was lower than 12V?
It’s a regulator, is it also a transformer??

6

Transformers only work for AC, and FRC control systems run on DC. However, you’re essentially correct in that the VRM functions as a bi-directional level shifter in order to provide a constant 12V supply.

7

I think it is a kind of “Boost Buck Converter” that steps up or steps down the DC voltage as needed.

They’re a cool piece of tech.

Dr. Joe J.

8

We used the new Robot Radio on 'Snow Problem. We did not encounter any brownout issues, just a few setup issues.

9

We used the new radio on Team Cockamamie with no setup or brownout issues.

10

Operation is completely transparent after the setup issues?

11

We’ve had some interesting connection problems, however I’m not entirely convinced it’s on the radio’s end (quick fix involves taking down the wireless card on the laptop). Our radio also is not from a KOP, so we ended up having to follow these instructions to update it manually. It’s possible that the firmware which shipped on the radio in the KOP and the firmware listed in that file are different.