# Advice on Ultrasonic sensors?

I am new to sensors and am looking for an ultrasonic sensor with a range up to 16-18 feet for very low costs (<$10). Most sensors I have found for this project are pricey relative to the cost I imagined. Are these type of sensors the best option if I am looking for low cost/long distance proximity sensing. This sensor is used for proximity purposes and does not need high accuracy. Any advice is appreciated. ## Answers and Replies Related Electrical Engineering News on Phys.org anorlunda Staff Emeritus I did quick searches for ultrasonic sensors on Amazon and eBay. I found several devices <$10 and even one for $0.96. I did quick searches for ultrasonic sensors on Amazon and eBay. I found several devices <$10 and even one for $0.96. They all have very low detection ranges (~cm), I am looking for 'long distance' (16-18ft). Nidum Science Advisor Gold Member Optical systems work much better at that sort of distance . Could you just use a cheap ready made laser distance measuring device ? anorlunda Staff Emeritus They all have very low detection ranges (~cm), I am looking for 'long distance' (16-18ft). Not all, this LED light claims 20 feet range for$8.99.
Waterproof LED Motion Sensor Light Wireless Security Light
I don't vouch for it. My point is only that you need to be a bit more diligent in your Internet serches.

berkeman
Mentor
am looking for an ultrasonic sensor with a range up to 16-18 feet for very low costs (<$10). Can you say what the application is? What accuracy and resolution do you need? Optical systems work much better at that sort of distance . Could you just use a cheap ready made laser distance measuring device ? I am open to any type of proximity device. The main constraints are price and range. Considering a lot of proximity sensors do not work through a solid medium, maybe a laser sensor would be better + I could conceal Can you say what the application is? What accuracy and resolution do you need? Its for sensing large objects at a construction job. Looking for a range of 16-18ft and just for proximity purposes (not distance measuring). One of the constraints is making it very low profile which requires a small sensor. Dimension of the encasing is cylindrical with rough dimensions of 55 x 20mm/ 3.15" x 1.9" (D*T). Also trying to keep the sensor low cost (<$10). Accuracy and resolution are not much of a concern since it mainly is for larger object detection

anorlunda
Staff Emeritus
Its for sensing large objects at a construction job. L
What do you require for the output of the sensor? A voltage change, say 0-5 V? A contact closure? An audible alarm?

What power will you provide? Batteries? 120 VAC?

Instead of proximity in any direction, could you detect an object breaking an infrared beam of light? If yes, then sensors similar to those used on garage doors might be appropriate?

The more specific you can be with requirements, the better the quality of the answers we can offer.

What do you require for the output of the sensor? A voltage change, say 0-5 V? A contact closure? An audible alarm?

What power will you provide? Batteries? 120 VAC?

Instead of proximity in any direction, could you detect an object breaking an infrared beam of light? If yes, then sensors similar to those used on garage doors might be appropriate?

The more specific you can be with requirements, the better the quality of the answers we can offer.
I honestly don't have any specifics as I am just learning and still trying to determine the best sensor around my constraints (price, range, and enclosure size). Either an audible alarm or visual light would be ideal. The power would be batteries as it is outside and often would be moved. From my understanding (which could be 100% wrong), garage door sensors require a receiver on the opposite side and I am looking to avoid that.

berkeman
Mentor
Its for sensing large objects at a construction job.
You do understand that the noise of a construction site will tend ot overwhelm the ultrasonic sensor, especially a cheap one.

You should consult your company's safety officer and insurance coordinator on this. What happens if the device fails temporarily -- could someone get run over?

dlgoff
Swake
Is this for counting purposes or theft prevention?

I would suggest an IR or laser beam based sensor.
16 feet might require some optics as with this sensor.
6 feet without optics and for 11\$: Search on Ebay for "CJMCU-530 Laser Distance Measuring Sensor"

You might need a reflector on the other side, but that really is not difficult to setup.

Eventually you can find an adaptive cruise control unit at the car scrapyard for cheap. Or some Lidar module but look out for the range.