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I have been a software engineer for many years writing code for websites/servers etc. I recently became intrigued with the idea of building land drones. I have decided to build a small tank that has a raspberry pi on it and can drive itself around and do stuff. In the beginning I will start off with only powering a raspberry pi and the turning of the wheels of this tank. I will put python code into the raspberry pi to make it do this. Down the road I will add a camera and potentially another small computer such as a Nividia Jetson Nano. I have the skills to do all the coding to make it work but I lack an electrical knowledge. The main problem I see that I have right now is what power source do I need to be able to power all of these things? I would like to buy some sort of a rechargeable battery that could power all of the things listed or just the raspberry pi and the wheels if I never get to adding the other stuff. I have read that the raspberry PI operates at 5v and the wheels of my tank operate between 7-12v. I have also read about the drive controllers that you can attach to the raspberry pi and how they can control dc motors. I haven't looked in too much detail about what will be required of the camera and some of the other possible items I will add as I am hoping to build incrementally.

Rather than ask for a solution to the above mentioned problem I would like to ask what is the recommended way to get my feet wet with this problem as well as any other problems a beginner robotics person like myself this kind of robotics would have?

I know I can go on amazon and look for books but I was hoping to ask the community for help in case there is a go-to resource that the community would recommend. Thanks in advance for any help.

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    \$\begingroup\$ This site is for specific questions about electrical engineering theory and design. It is not a referral service, but people might offer a few suggestions in comments. There are dc to dc converters to convert a battery voltage to various voltages. Motor drivers for raspberry PI accept the higher voltage for motors directly from the battery or from a converter. There is quite a bit of mechanical engineering in figuring out what torque and speed is needed from a motor to drive something that you build. I am voting to close the question. \$\endgroup\$
    – user80875
    Mar 21, 2021 at 17:32
  • \$\begingroup\$ Practically you need some understanding of basic physics, to understand how mechanical work relates to electrical power, how motor speed and torque relate to your tank's speed and climbing ability, and the power needed to overcome friction. And how the same motor speed and torque relate to battery voltage and power. \$\endgroup\$
    – user16324
    Mar 21, 2021 at 18:29
  • \$\begingroup\$ To get your feet wet? You can buy a "USB power bank" from any electronics store, that will output 5V and a few amps, for at least several hours (unless it's a cheap crappy one). \$\endgroup\$
    – user253751
    Mar 21, 2021 at 18:33

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A 12V battery, and a 12V to 5V 3A dc to dc converter. Would be the start. I would use opto-isolators on the GPIO side just so absolute catastrophic failures on the motor side never have a chance to damage the Raspberry Pi computer.

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If you have mobile robot first, you need to consider active time like how long you need your robot to operate for single charge. Second, how much power draw for every load youcan calculate or measure from real system. After that you know Watt per hour of your energy source. After that is your voltage. You can convert it up or downusing dc convertor with some conversion loss. So I suggest to choose voltage to match high power load like motor and choose load with same voltage to avoid conversion loss. Lastlu, You need to calculate maximum current of your system like worst case scenario. Now you khow voltage and watt per hour you can select battery that match your application that maximum current will specify battery type or discharge rate of battery. Note: don't forget some safty factor about 70% to 80%.

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The first thing to do is draw up a list of all the things that need power. Work out what voltage they require, and how much current. Some things - especially motors - draw big current surges when they start up. So find out the typical running current and the peak current.

Failing to allow for the start-up current of the motors is liable to result in a sudden drop in voltage on start-up, that then crashes all the microprocessors.

Once you've done that, work out what battery will be able to supply enough power to the most power-hungry things. Ideally run them straight off the battery. Use DC/DC converters, boost/buck regulators or even LDO (low drop-our) linear regulators for the rest. Read the manufacturer's data sheets and don't cut corners. If they say you need decoupling or reservoir capacitors, don't miss them out.

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