Wheeled robot motors: with or without encoder

Help & Support Robot Parts
1

dear fellow makers,

I have a question, my wheeled robot car will travel on 2 linear rails.
I am choosing the DC motors, should I use encoders as well? or the rails are just fine and therefore not necessary?

NOTE: I will measure the speed using a infrared distance sensor measuring the distance to the end of the rail

thanks

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2

Hello @FrankLG,

Welcome to RobotShop community.

If it’s on a linear rails then the infrared sensor should be enough to provide you with a rough estimation of the speed.

Let us know if you have further questions.

Sincerely,

2 Likes
3

Thank you so much for the fast reply @Ebram

I’m sorry to bother you again.
I’m building a 2WD car but don’t find anything suitable to mount the rear non driving wheels to the chassis. Would you have any suggestions?

4

Hello @FrankLG,

Thank you for your reply.

Please provide us with some pictures of the chassis you have and the wheels you are using.

You can also use a ball caster instead of the 2 non-driving wheels:
https://www.robotshop.com/en/catalogsearch/result/?q=ball+caster&order=relevance&dir=desc

Awaiting your reply.

Sincerely,

1 Like
6

Hello @FrankLG,

Thank you for your reply.

Have you bought the wheels already?

If yes, you would need a mounting bracket that you can connect the wheel to it.

For a smoother rotation you can use a small shaft connecting the wheel to a ball bearing:
https://www.robotshop.com/en/catalogsearch/result/?q=ball+bearing&order=relevance&dir=desc

Let us know if you have further questions.

Sincerely,

7

Hi @Ebram

Thank you…

I assume the mounting bracket i have to create it right?

I’ve yet bought the wheels, why?

8

It’ll all depend on the design of the robot and how smooth you need these wheels to rotate.

You can connect these two wheels with one shaft going through the body of the robot and resting on two ball bearings, one on each side of the robot.

9

You are right…
Thank you a lot for your useful tips…

For other questions, before buying my elements, could i ask here or shall I open a new thread?

10

You can ask here.

If it’s a general question, you can open a new thread with a “General Discussion” tag attached to it.

11

ok…

I am searching now a range finder / distance sensor to measure the distance from my robot to a bottle, min distance 2 cm max 1m.

I have seen that there are many types out there, IR or laser or sound. Which one would you recommend?
NOTE: the motors don’t have an encoder, therefore they rely on this sensor for speed.

12

Can you provide us with a clearer description of the project you are trying to build so we can have a better understanding of it?

Will this be an autonomous robot?

What’s the relation between the robot and the bottle?

Is this bottle see-through? made of glass?

14

Hello again,

Thank you for explaining.

There’s a wide range of options to choose from for this task so it mostly depends on the budget and the accuracy you need.

You can use a simple ultrasonic sensor such as this one:

Let us know if you have further questions.

Sincerely,

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