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Question

I am making a study on robotics that uses a radar.

but I don't know;

what type of sensor is used in making radars?
like radar on a ship.

Can a radar like that map a certain area? or it needs an overlaying of an electronic chart or map?

thank you, please helpppppppp meeeeeeeeeee...

jw0752 · Answer

Hi Raymond, You may want to Google LIDAR which is similar to RADAR but uses pulsed laser to detect objects and surroundings. Ultrasound and PIR are also useful sensors for robots. Radar can be used but since it is more sensitive to metal and reflective object I am not sure how applicable it would be to a general purpose robot. I am not an expert so perhaps some of the other guys on the forum will also render their opinions. John

DAB · Answer

Typically radar refers to radio frequencies. In Robotics you will find ultrasonic sensors for short distance (0-2 meters) measurements and Lidar for longer distance (.02 - 100 meters) measurements. There are some experiments going on with millimeter wave sensors, but those are not usually associated with robots yet. So using the term radar with robots seems odd as there is limited utility. Now if you are talking about aerial vehicles, they you will find radar included as a part of the avionics package, but you are not talking about inexpensive robots in this case. So I suggest you supply us with additional information to narrow the context of what you want to know. DAB

silentknight14th · Answer

Thank you for your suggestion. I'm gonna search for it.

Former Member · Answer

I got involved in robots when I was younger, back then we used to use sharp ir rangefinders https://www.robotshop.com/uk/sharp-gp2y0a21yk0f-ir-range-sensor.html and mount them to a servo so they could scan an area. Theres lots of different rangefinders with different distance capabilities. Because light doesnt spread as much as sound they were more precise than ultrasound. The radar you see on ships require a lot of radio energy to work, so much so that the radar units have to be disabled when the ship is in port to prevent risk of cancer to anybody in its close field, theyre usually mounted high enough to avoid the radio waves affecting the crew on board, it just goes over them.

DAB · Answer

Hi Raymond,

Trust me, a lot of people have been looking for a cheaper way to do what you want.

Many things have been tried, but so far nothing has demonstrated that it is a reasonable solution.

Engineering 101, define carefully what you want to do.

Find something that is acceptable for your specific application.

Build and test.

In the 100 meter range the Lidar will work and costs roughly 100 USD to get a reasonable sensor.

RF sensor suffer from near field issues, so a traditional radar at those ranges would actually be more expensive and less reliable.

If a sensor exists for that range the is better or cheaper, then it is being kept quiet.

Still it does not hurt to think about the options. You might be able to use a pin diode with a directional antenna, but you will have to do some testing on frequencies and power ratings.

Don't forget, any RF emissions fall under strong legislation about interference, so unless you have a good quality anechoic chamber to work in, you probably should not be working in free space.

These are not simple issues.

DAB

jomoenginer · Answer

silentknight14th wrote:

Thank you,

I have been searching a lot for some sensor
I was inspired by the radar which marines used and those sea mark that appears on their radar.
I was going to place it in land, but buying a marine radar would cost so much, and i want to find an alternative a much cheaper one.
Which can cover large distance, do you have a suggestion for me? Thank you.

Uh, is this not a red flag for some folks?

For the poster, I would suggest doing a Google search, but if you are unable to find any specifics regarding this technology then it is a good clue that companies more than likely would not like the data to reach the wrong hands.

Personally I would caution anyone looking to providing info in this thread especially if it is something they had worked on in the past. Just saying.

silentknight14th · Answer

Thank you. I was confused too, our school named it robotics but I find it hard to conclude that it is robotics rather than it is a mechanical and electronics thing. I am thinking of a design of a device that can be used in forestry regions. and can monitor such things. so I decided to use a radar, but I don't know what kind. so Lidar can cover a distance up to 100 meters? is there any similarities on programming of lidar and ultrasonic sensors? and how much is the cheapest one?

fmilburn · Answer

I suggest watching this video on less expensive lidar units as well as a description on how lidar works: https://m.youtube.com/watch?v=ddxguAzzzJE He also has videos on how to program various distance measurement sensors including ultrasonic sensors.

jw0752 · Answer

Hi Raymond, Each type of radiation has its own absorption and reflection characteristics. Microwaves are a frequency that is easily absorbed so they may not make a good radiation for scanning. This is why they are used in microwave ovens. You would send the waves out and rather than reflecting back to your sensor they would be absorbed by the environment. You will have to determine the material in the environment that you want to detect and to what precision and then select the type of radiation that will best serve your needs. John

silentknight14th · Answer

Thank you, I have been searching a lot for some sensor I was inspired by the radar which marines used and those sea mark that appears on their radar. I was going to place it in land, but buying a marine radar would cost so much, and i want to find an alternative a much cheaper one. Which can cover large distance, do you have a suggestion for me? Thank you.

silentknight14th · Answer

thank you but can I also use a microwave sensor? to cover like a hundred meters of distance?

jw0752 · Answer

Hi Raymond, Sorry I understand some of the physics but I have almost no experience with the type of sensor you are looking for. Some of your challenge may be that you are not real specific on what you want to sense. Unless you have AI level processing power available do not expect to be able to sense the world like we can with our eyes. Most robotic systems are geared to object avoidance or object targeting. Most robots use more than one sensing system to allow them to do better in special situations. You may want to study up on autonomous vehicles to see what type of sensors they are using. My robot vacuum cleaners in my home use LIDAR, touch, and I suspect Infrared sensors in their systems to navigate the house. John

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