Alternative to the PDP and VRM

Technical Electrical
1

As a second year team we are short on resources and only have one PDP and VRM that we reused this year for Stronghold (it is in the bag). I am looking to make last year’s chassis drive-able and looking for a cheap alternative to buying a new PDP and VRM.

My plan involves a marine supply fuse box that fits the “MAXI” 40A fuses, any other alternatives out there that teams have used?

I am still trying to figure out how to power the Roborio safely any ideas.

 "Power Requirements
 The NI roboRIO requires a power supply connected to the power 
 connector.
 Power supply voltage range 7 VDC to 16 VDC
 Power Consumption
 Maximum 45 W
 Typical idle 5 W"

Thanks for your ideas!

2

If you can get a hold of one of the old Power Distribution Boards that is the easiest swap. Powering the RoboRIO isn’t hard since it is designed to just take battery voltage. Just put a small fuse inline with it before wiring it to the battery. A MAXI style fuse panel will work for your motors as well like you suggest.

3

Note that if you’re using CAN for anything (other than your non-existent PDP) you’ll need a 120ohm termination resistor at the end of your chain to stand in for the missing PDP.

4

I assume you are also using the old radio and you need (or already have) a source of 5V and ~2A.

If you ask around teams in your area, someone will probably loan/give you a 12V to 5V converter that used to be required for the radio, due original radio being 12V. It looks like this one (common style):
http://www.amazon.com/RioRand-Waterproof-Converter-Voltage-Regulator/dp/B00JM07LMY/
AndyMark and others sell this one:
http://www.andymark.com/product-p/am-3068.htmServoCity has this Step up/Step down one:
https://www.servocity.com/html/5v_step_up___down_voltage_regu.html#.VtE1M5wrI1I
I haven’t used either of the last 2 products, but I probably am going to buy the last one (if I can’t find a similar higher amp one) to power some cameras rather than a 2nd VRM. Of course, you could always make your own circuit with parts you might already have.

5

There are cheap PDB for the cRIO on eBay right now.

6

We are in a very similar situation. However we are trying to power a PCM and RoboRIO using one of the old PDBs, as well a (hopefully) the new radio. Only catch is that we don’t have a spare VRM.

Is there any downside to powering the roboRIO directly from the 12V output on the PDB? How about the PCM?

7

It’s fine to run off the 12v output with a small value breaker.

8

Thanks for all the input, we went with a Marine supply breaker for the snap action fuses (6 on a panel) ~75$, and for the VRM we took a cell phone car adapter USB connector ~6$ and soldered onto the converter inside it takes 12V in and puts out 5V 2A. All up and running now.

Thanks again

9

Hi,
Klhutchi our team is in New York, we should have some older pbd’s knocking around the lab. Message me privately if you still need one.
Karl

10

The only downside it you have no ‘brownout’ protection. If battery voltage does not fall too much you will be fine