Detect when door is closed with 100 percent precision

Thread Starter

grcshekar

Joined Jan 8, 2020
31
I am building a smart door based on RF and solenoid for my college project. But I need to open the door side ways as shown in image so linear actuators wont work. It is just acrylic door weighting 250 grams.

So how do i achieve this part. I mean opening door sideways as shown for light weight door
 

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Thread Starter

grcshekar

Joined Jan 8, 2020
31
I heard linear actuator is for sliding only !!! Can you please suggest the one which i can use for this type of door as it is very light weight
 

Delta prime

Joined Nov 15, 2019
425
But I need to open the door side ways as shown in image so linear actuators wont work
You could pick a design of your linear actuator which will open and close your door sideways you can also choose the amount of force and time it would take to open or close. if you like. if you need help on the Rf side a schematic would help.
https://www.linearmotiontips.com/design-guide-linear-actuators?campaignid=8769675587&adgroupid=89446533998&gclid=CjwKCAiA1fnxBRBBEiwAVUouUrPuaPNJH6owkV1Tae59Q0MtmcODYni75oclwMUM1NdGlOhdyLhjzhoCh6oQAvD_BwE
 

Thread Starter

grcshekar

Joined Jan 8, 2020
31
Hi Experts !

I have seen reed switch, magnetic sensors etc which works with 5 mm difference in distance.

I need to know when door is exactly in closed position with 100% precision. Its like two plates must touch each other and trigger HIGH or LOW. Which component can I use for this ? As the door opens side ways chances of limit switch getting damaged is also more. so any other component suggestion with low cost as it is a DIY project for hobby in colllege
 

MaxHeadRoom

Joined Jul 18, 2013
21,189
One of the cheapest ways would be to obtain a small/cheap DC gear motor and make up a mechanism such as this, This is a typical method that door-closer's use .
Max.
 

KeithWalker

Joined Jul 10, 2017
1,134
A microswitch would be the simplest and most robust solution. Anything else like magnetic switches, photo, ultrasonic, capacative and resistive sensors would all be subject to external forces which could interfere with their operation.
Keep it simple!
Keith
 

MaxHeadRoom

Joined Jul 18, 2013
21,189
Use a Honeywell SS400 device, and If possible, embed it in the door jamb etc and use a small button magnet on the door.
No Moving parts.! :cool:
Max.
 

hexreader

Joined Apr 16, 2011
425
As ronsimpson says... 100% is not achievable. Would you care to correct your specification to 99% ? 99.99% ? 1 in a million ? Estimated average of 1 failure every 10 years?

How about 3 micro-switches or magnetic switch, and some kind of logic (micro-controller? ) that selects 2 out of 3 sensor indications to cope with sensor failure?

But then micro-controllers fail (especially when power fails), so you may need 3 micro-controllers and three battery backup supplies to be sure.

Or just keep it simple and buy the best quality micro-switch that money can buy (check datasheet for reliability figures) and settle for close to, but less than 100% reliability with the simplest possible circuitry. Even the datasheet is only part of the story. A badly installed switch will reduce reliability.

Regular maintenance checks might reduce risk factors.

Just my random thoughts.... feel free to ignore.....
 

djsfantasi

Joined Apr 11, 2010
6,692
MaxHeadRoom
Hall effect sensor and magnet?? Again if magnet is 5 mm close it gets activated
Use Hall Effect sensor and magnet to detect door position.

Use microprocessor to process the sensor and implement process to confirm the door is actually closed.

After Hall Effect sensor detects door closed, delay for a short period of time to allow door to close the remaining 5mm and successfully latch.

Mount a solenoid in the door jamb to kick open the door. After the above delay, activate the solenoid to slightly push the door open. Check the Hall Effect sensor to see if the door is open.:rolleyes:
 

Thread Starter

grcshekar

Joined Jan 8, 2020
31
Hi

I am building a automated dog crate door. While closing it, I need to check if dog is passing through a 12 mm door frame including its tail. Any High precision motion or IR sensor to achieve this please
 

MaxHeadRoom

Joined Jul 18, 2013
21,189
There appears to be two issues /questions going on here!
Mechanism to operate the open/closing of the door and the detection of closure! :confused:
Max.
 
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