I have to sit in line with my truck. I sure could use a 5 min. nap sometimes, but have to stay awake all the time.
Here is what I want to build. I want to make a wooden box to sit on the dash of my truck. When I pull into line with in 10-25 ft of the back of the truck in front of me I want to flip on a switch and close my eyes. I want a buzzer to go off when the truck ahead of me moves, be it 5 or 20 min. later.
Do I want a ultrasonic sensor, like #2157351 from Jameco? Plus a DC 3-24 V Electronic Ton Buzzer Alarm 85 dB ?
I need a motion sensor system that works in reverse of normal. lol. Something that tells me when the truck in front is gone, not arrived.

Thanks.
Nelag

 

Won't work through a windshield- it's an ultraSONIC sensor- sound doesn't like to go through glass.
You could make it work with the sensor mounted on the bumper.

 

Won't work through a windshield- it's an ultraSONIC sensor- sound doesn't like to go through glass.
You could make it work with the sensor mounted on the bumper.

Thanks. I will look for an outdoor sensor if I go that way.
Someone on NewAg Talk suggested using a Park Zone Precision Parking unit as sold on Amazon. It is a unit that tells people when to stop their car in the garage. They posted," Wire a relay into the lights and use the normally closed side of the contacts for your buzzer. Would reverse opeation." Can't say I understand all that, but do you agree with their statement and think such a unit would work for me? Thanks for your interest. Nelag

 

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Someone on NewAg Talk suggested using a Park Zone Precision Parking unit as sold on Amazon. It is a unit that tells people when to stop their car in the garage. They posted," Wire a relay into the lights and use the normally closed side of the contacts for your buzzer. Would reverse opeation." Can't say I understand all that, but do you agree with their statement and think such a unit would work for me? ..............

Not clear. It says it detects the movement and turns on when you are approaching the unit from 12-16 feet or so, but not sure if it detects anything when moving away from the unit, as would be the case for you.
You could try it and see, and return it if it doesn't.
Also the unit is not designed for outdoor use so that's also a problem.

You could perhaps use a backup sensor such as one of these on your front bumper, since they are designed to survive the elements, but they are only good to about 6-8 feet.
Would that be a sufficient distance?

 

A parking sensor could be emitting sound continuously because of the proximity. Contrary to what you need, it will allow you to sleep when the truck ahead moves away.

 

A parking sensor could be emitting sound continuously because of the proximity. Contrary to what you need, it will allow you to sleep when the truck ahead moves away.

Yes, that is likely.
First I wanted to establish if its operating range was sufficient for his purpose.

 

A parking sensor could be emitting sound continuously because of the proximity. Contrary to what you need, it will allow you to sleep when the truck ahead moves away.

Unless the unit is completely integrated that can be dealt with by taking it's output and using a simple circuit to "invert" it, along the lines of what was recommended to him in another forum.

Of course the cheapest solution is to just use the driver behind him as his motion detector and they guy's horn as his wake up alarm.

 

I would get a cheap parking sensor and modify it...

 

Industrial sensors are readily available for any range and environment, but are typically pricey.Still, you could get one that will operate DC, and 12V, and has SPDT contacts (output) and connect it to a 12VDC buzzer. Simply power it, by wiring it through a switch, or using a cigar lighter adapter and leaving it unplugged until you're up behind another vehicleYou could use a relay to get that contact action if you cant find a sensor with double acting output contacts.

 

Perhaps a cheapo PIR sensor could detect exhaust heat change/movement when the vehicle in front moves?

 

Modified parking sensor as stated is the best solution or use the old way knot a wire to the bumper in front of you and connect it to a bucket of water mounted above your head.

 

Perhaps a cheapo PIR sensor could detect exhaust heat change/movement when the vehicle in front moves?

What if the car in front of you is a Chevy Volt? Or an 18-wheeler?

 

Just make sure you're not behind one .