sensor to read distance from car in garage - Page 1
Forum section: electronics / beginners

author: sairfan1
author_rank: Frequent Contributor
timestamp: August 17, 2020, 11:45:15 pm
content: its a small DIY project, i have very narrow space in my garage when i park my car in the garage there is hardly about 2 or 3 inches space from wall (on front side), i want to build some arduino based project to display distance in cm,it will be installed on wall and display the distance in cm/inch, i have idea of ultra sonic sensor, while reading articles about it i learned that on some angled surface it does not get signal back, i also came across some laser sensors i believe they are IR based (may be) not sure if they will work goodI want to ask the question if anyone there has experience which sensor could work better in this scenario

author: Fraser
author_rank: Super Contributor
timestamp: August 18, 2020, 12:05:20 am
content: I had a similar scenario a few years ago. I wanted to check the distance from my cars bumper to the rear wall. I looked at ultrasonic distance measurement and all sorts. I asked a car parts dealer about the “traffic light” ultrasonic garage sensor he sold..... his words to me were a surprise ...... “Sir, would you really trust the bumper of your £30K+ car to a £20 sensor gadget built down to a minimum cost ?” He was right. The better solution was a physical ‘stop’ to prevent my cars rear wheels going beyond certain point and so stopping me hitting the rear wall. I use a pair of heavy concrete house building type blocks. Worked a treat. Simple, effective and cheap.With that in mind, have a think about simple solutions to your scenario that do not rely on a technical solution that can fail you. You could consider a wood batten screwed to the floor that prevents your wheels going too close to the side, like is used in some drive through car washes, or you could position a mirror on the end wall that lets you see the gap between your car and the wall.The KISS principe is often cheapest and most reliableIf you just want to build an ultrasonic distance meter for the fun of it, then no worries. I did that years ago. One design used TX and RX ultrasonic transducers with very short TX pulse duration for ‘time of flight’ calculations at short distances. I also used an ‘all in one’ ultrasonic module as used in old Polaroid instant cameras. They are sold for distance measuring projects using Arduino etc. They use ‘time of flight’ measurement as well. Ultrasonic can be deflected in some cases resulting in a low reflected signal level. This can make such measurement unreliable in some cases, especially against soft targets that provide a poor reflection.10GHz Radar modules are also fun to work with. They used to be expensive and complex, now they are an inexpensive PCB module with the antennas and electronics all in place for the experimenter to use. Doppler shift is commonly used when these modules are used in movement detection scenarios. You would want ‘time of flight’ to measure true distance and the modules may not provide that capability.Another option is a ‘break beam’ system where a narrow beam of light, such as a laser illuminates a sensor. If something comes between the light source and receiver sensor, an alarm in generated. In your case, the cars side would break the beam and alert you to the fact that you crossed the safety zone. You would have to work in the NIR spectrum to avoid daylight interference with the systems receiver sensor. If the receiver sensor became illuminated by extraneous light that looked like its transmitter signal, you gave a fail UNSAFE condition ! The use of a coded or non CW signal from the TX and decided by the RX is an option if spurious input detection is desired.Have funFraser

author: ledtester
author_rank: Super Contributor
timestamp: August 18, 2020, 12:28:22 am
content: Quote from: Fraser on August 18, 2020, 12:05:20 amSuspended tennis ball:https://youtu.be/QGdkI59e960

author: MarkF
author_rank: Super Contributor
timestamp: August 18, 2020, 01:12:54 am
content: You might have a play-around with this:Adafruit VL53L0X Time of Flight Distance SensorApprox. 30 to 1000mmPlus, Adafruit provides Arduino demo codehttps://learn.adafruit.com/adafruit-vl53l0x-micro-lidar-distance-sensor-breakout/arduino-code

author: sairfan1
author_rank: Frequent Contributor
timestamp: August 18, 2020, 02:11:30 pm
content: We have a folding table tennis in our garage, some time we park our car on driveway to play table tennis that's why i can't do things like handing a ball or putting something to stop the wheels, if i could not find anything workable then "break beam" could be the solution.

author: ledtester
author_rank: Super Contributor
timestamp: August 18, 2020, 02:27:10 pm
content: Another idea:https://youtu.be/Com8AXgoOZs

author: sairfan1
author_rank: Frequent Contributor
timestamp: August 18, 2020, 03:43:02 pm
content: I'm an electronics guy and my brain goes back again and again to electronics solution, sorry for that.What if we install some laser light on the ceiling spotting some place on dashboard/car top? may be we can add some further mechanics like after car properly parks it goes off or turn on some indicator?or can we do something that exactly indicate that car is at its absolute position, like at one spot tracing from the top turns on LED on front wall,Sorry guys just sharing my thoughts.

author: MarkF
author_rank: Super Contributor
timestamp: August 18, 2020, 03:52:59 pm
content: Quote from: sairfan1 on August 18, 2020, 03:43:02 pmMaybe you could experiment with a 2nd set of garage door photo sensors that keep the door from closing on your cat (or small child)I never looked to see if they are just DC powered with a photo sensor and focus lens. Would be easy to mount at bumper height.

author: Dabbot
author_rank: Regular Contributor
timestamp: August 18, 2020, 03:56:43 pm
content: If you're keen on an electronic solution, purchase a couple of the HC-SR04 modules to play around with.Ultrasonic sensors are already used extensively for these purposes, for example in shopping mall undercover car parks.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: August 18, 2020, 04:03:54 pm
content: I too am a fan of the simple solutions, chocks on the floor or a tennis ball.But if you really want a sonar sensor I highly recommend the Maxbotix ultrasonic sensors. Even their lowest cost modules are highly accurate and can deal with difficult targets. If you are as constrained as you suggest by your garage you should be able to mount the sensor so that it sees the license plate or other appropriate surface and thus eliminate the problem of reflection off an angled windshield or the like.I also wouldn't worry too much about the relative value of the sensor and your car. I doubt if you will be cruising into your garage at 20 km/hr planning to slam to a stop at the perfect distance. Damage will occur because of things that even the wheel chocks or tennis ball can't deal with. The cleaning bucket someone left against the wall that you didn't notice, or something like that.

author: voltsandjolts
author_rank: Unknown
timestamp: August 18, 2020, 04:20:30 pm
content: I use a tennis ball hanging from the ceiling...when the ball touches the windscreen, STOP!

author: Benta
author_rank: Super Contributor
timestamp: August 18, 2020, 04:32:09 pm
content: Use one of these mounted on the rear wall. When the car bumps into the rubber part, you'll get an audible signal.Due to the ingenious use of soft rubber, it will not damage or make marks on the car.No batteries needed.

author: Fraser
author_rank: Super Contributor
timestamp: August 18, 2020, 09:46:13 pm
content: Well is you want to go “full electronic” overkill, how about installing a small CCTV camera equipped with IR illumination and feeding a monitor on the wall in front of you so that you can see how close you are getting to the wall. You could add a remote control to turn the system on and off, or have the system self activate using a PIR detector and delay timer to switch the unit off after a set time. The PIR will see the cars Thermal profile as it approaches easily. Room occupancy PIR sensors are now common. Totally ‘over the top’, but if you are going to throw out the KISS principle, you may as well do it in style !You could build the whole system for less than $100 these days.Fraser

author: Doctorandus_P
author_rank: Super Contributor
timestamp: August 18, 2020, 11:16:46 pm
content: Another mechanical solution is to use some pieces of wood from the wall to the front wheels.You can gently drive your car into them and feel when its hits the wood, with about the same feeling as driving onto the sidewalk.Or some mechanical system that pushes a lever or a rope (Pulley's) and has some mechanical advantage, and make some scale which you can calibrate.You can also tape the horn with rubber bellow (fart pillow?) to the floor in the right spot so it makes noise when you drive over it.

author: Psi
author_rank: Super Contributor
timestamp: August 19, 2020, 12:04:30 am
content: GP2Y0A02YK0F is another sensor that can detect long range.Something like 20cm to 1.5meters.Analog output.They're all over aliexpress for $5 or so