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I'm making an indoor companion bot, but requirement is that it easily traverse thick carpet, which is common all across the US in houses. Seems no better platform than 'Roomba' which was designed for that. (iRobot Create 2)

I will have to power several cameras, a couple servos, webcam speakers and a Jetson xavier nx.

The PRIMARY requirement is that the robot can autocharge it self. It is 100% unacceptable to have any forced physical interaction. Similar to the Vector robot, it is just suppose to be a little pet for entertainment, and needs to charge itself.

I have skills in the programming, but I need to avoid the wiring, soldering part, volts-watts current limits etc. so it can be used in a programming (not electronics) teaching setting. I want to know what off-the-shelf things to buy be able to just assemble it and work on the code.

budget limit besides cameras, jetson, and 'roomba' is $500 USD

"how can I power a jetson and the mentioned peripherals FROM THE BATTERY of the Create."

  • The comments about price were to 'quantify the solution space'
  • The comments about 'self charging without intervention' were to clarify the restriction of not using external battery packs, and not have the solution interfere with Roomba's autocharging feature
  • The comments about the choice and the robot were to clarify that other bases could potentially be solutions but would need to be as effective on carpet and handle weight and self charge
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  • $\begingroup$ shopping questions are off topic here ... you can ask for a confirmation that a product exists, but you cannot ask where to find the product $\endgroup$
    – jsotola
    Aug 7 at 17:38
  • $\begingroup$ @jsotola no. I didn't. You saw a dollar sign and failed to read the question. $\endgroup$ Aug 8 at 20:54
  • $\begingroup$ there is no specific question about robotics ... I want to know what off-the-shelf things to buy is a quasi-question about shopping $\endgroup$
    – jsotola
    Aug 8 at 21:52
  • $\begingroup$ @jsotola let me rephrase it for you. "what components are needed to draw power for a jetson, camera and speakers, from the battery of an iRobot Create, where we're not trying to ultra-minimize cost". $\endgroup$ Aug 9 at 14:49
  • $\begingroup$ oh wow, looks like you guys are going to make me do all kinds of research into Create and brush motors and current limits and voltage regulators just to figure out what you already know as far as what I need to get electrons into the peripherals. $\endgroup$ Aug 11 at 14:26
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The Create2 Open Interface Spec (warning: direct PDF download) gives a description of the pinout on the connector:

Create2 connector pinout

You can see there that you can tap into the Create2 battery by attaching to Pin 1 (V+) and Pin 7 (GND), etc. There's a note under this diagram that states:

Pins 1 and 2 (Vpwr) are connected to the Roomba battery through a 200 mA PTC resettable fuse. The continuous draw from these two pins together should not exceed 200 mA. Do not draw more than 500 mA peak from these pins, or the fuse will reset.

There's a document about using the Create2's battery power (warning: direct PDF download) that gives some more information, stating in part:

SERIAL PORT

Ratings

Voltage 20.5V – 10V

Current 0.2A

Power 2W

Always On: The serial port power comes from either the charger when the robot is on the dock or from the battery while the robot is running, serial port power is always on. We recommend installing an on/off switch between the serial port and your project. Remember to turn off your project when you’re done. If you leave your project on and don’t return the robot to the dock to charge you will eventually deeply discharge the battery and damage it.

If you're going to power something off the battery, you'll need a voltage converter that can handle at least a 10-20.5 volt input range. Any converter capable of handling that range should work, then you'd just need to determine what the output voltage is that you need and the power requirements to make sure you're staying under the 2W serial port requirement.

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  • $\begingroup$ Thanks Chuck. The issue is that the jetson takes 10-15 watts. There are versions that use 5V and versions that use 19V. I have heard that people tap into the 'brush motor' or something to get higher power output. Seems that's what I need, but I need some way to turn it into a stable 5V 10 watts at least. $\endgroup$ Aug 13 at 15:22
  • $\begingroup$ @AwokeKnowing - The link I put in the answer about the battery power (second link) will explain how to tie into one of the motors. The third link is a set of filters on the Digikey website (no affiliation) for DC to DC voltage regulators that have an input voltage range of at least 10-20.5 volts. As mentioned, add a filter for your power (I'd do everything 15 W and up) and the voltage or voltages you want, then sort ascending by price. Should be able to find whatever you need there (but there are always other places to shop, too). $\endgroup$
    – Chuck
    Aug 13 at 17:24
  • $\begingroup$ the doc says "you will need to access the main brush connector and add an inductor". I don't know what is this 'inductor' that i need. is that taken care of by the voltage regulator? $\endgroup$ Aug 13 at 19:30
  • $\begingroup$ @AwokeKnowing - The upper-right of page 1 of the Battery Power document gives you the inductor specs - 2.2 mH, 1.5A if you're attaching to the main brush, 2.2 mH, 0.5A if you're connecting to the side brush or vacuum. Beneath each item is a list of manufacturers and part numbers. A description of why the inductors are required is on the bottom-right of the second page. $\endgroup$
    – Chuck
    Aug 13 at 20:32

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