# Robot Parts Buying Checklist: Free Printable

> A free checklist to run on any robot part listing before you pay: specs, interface, seller and arrival checks.

Canonical: https://roboticsengineering.in/free-library/robot-parts-buying-checklist/ | Published: 2026-11-04 | Updated: 2026-11-04

**One checklist to run on any robot part before you pay.** It works for motors, drivers, sensors, batteries, boards and kits. It contains no prices and no brand recommendations. Compare current listings yourself.

## Before you search

- Write down what the part must do and the numbers that matter: voltage, current, speed, torque, range or resolution.
- Decide your supply voltage and logic voltage first, so you can filter parts that do not fit.
- Write your budget as a range and leave room for spares.

## Read the listing

- Is there a datasheet or a clear specification table, not just marketing words?
- Do the rated voltage and current cover your use with a margin?
- Is the interface stated (I2C, SPI, UART, PWM, analogue)?
- Are the pin names and connector type shown in a photo or diagram?
- Are example code or libraries linked, and do they match your board?

## Check the seller

- Seller rating, return window and who pays return shipping.
- Whether the item is new, used or a clone, and whether the listing says so.
- Delivery time, and whether you can wait if the part is out of stock.
- Whether you get a proper invoice.

## When it arrives

- Photograph the parcel and the part before use.
- Check the markings match the listing.
- Test on the bench with a current-limited supply before fitting it into the robot.
- Keep the invoice and listing screenshot until the return window ends.

For planning a full build use the [project cost calculator](https://roboticsengineering.in/robotics-project-cost-calculator/). Keep notes in the [bill of materials template](https://roboticsengineering.in/free-library/robot-bill-of-materials-and-test-log-template/). All current buying guides are in the [buying guides category](https://roboticsengineering.in/category/buying-guides/), and the [Learn hub](https://roboticsengineering.in/learn/) explains the ideas behind the specifications.

Last reviewed: November 2026. Free to copy and adapt for your own project, with credit. Written, checked and maintained by [Jignesh Panchal](https://www.linkedin.com/in/jignesh-s-panchal/) of [Jaadu Digital](https://jaadudigital.com/). See the [editorial standard](https://roboticsengineering.in/editorial-standard/).

## How to read the numbers

- Rated voltage and current: pick parts whose continuous rating is above what you need. For a motor driver, compare its continuous current with the motor’s stall current, because stall draws the most. If a motor stalls at 1.2 A, a driver rated for 2 A continuous gives about 1.7 times margin.
- Peak and continuous are different. A battery or driver listing may quote a short burst, so look for the continuous figure.
- Capacity: a 2,000 mAh battery supplying 500 mA lasts about 4 hours in the ideal case, and less in practice. Use the battery runtime calculator.
- Logic level: a 3.3 V board needs a part that accepts a 3.3 V signal or a level shifter.

## Signs of a poor listing

- No datasheet and no part number, only a brand-like name.
- Capacity or power claims that look far above similar parts at a similar size.
- Photos that do not match the title, or different photos in each review.
- No contact details or return policy.

## A short example of using the checklist

Say you need a driver for two small motors that stall at 1.2 A each. Write the requirement first: 2 channels, at least 2 A continuous each, motor supply of 7.4 V, 3.3 V logic. Then filter listings by those numbers, check the datasheet for the voltage drop, and note whether the pins are labelled in the photo. Compare two or three candidates in a small table, and keep your notes for the bill of materials.

## Before you click buy

Check the total including shipping and tax, the delivery date and the return window. If a part is for a deadline, order spares of cheap parts that fail easily.