automatic door opening by microcontroller

hi i m saurabh i need ur help for circuit as well as well as program for automatic door opening control by micro controller 89c 51. ok i want to operate one door by proximity sensor which actuate dc motor through 89c 51. the proximity sensor sense the man or object. and actuate the dc motor in forward direction then after some time the door closes when the man passed away.

Tell us the whole scheme what you want to do so that we can tell you about the circuit and program.

Added after 9 minutes:

Tell us the whole scheme what you want to do so that we can tell you about the circuit and program.

hey circuit diagram is very simple
i suggest you as
40,31 to 5 v
10uf cap in between 5v and pin no 9 and one pull down resistor 10k ohm to ground
connect crystal 11.0592 to 18 and 19 with 33pf cap
20 to ground(complete minimum circuit)
you can assign any port as input say p1.0
say p2.0 to dc motor for forward
p 2.1 to dc motor for reverse
for any modification like visual indication ,beep alarm you can connect led ,buzzer to any pins

sammkt005 said:

hi i m saurabh i need ur help for circuit as well as well as program for automatic door opening control by micro controller 89c 51. ok i want to operate one door by proximity sensor which actuate dc motor through 89c 51. the proximity sensor sense the man or object. and actuate the dc motor in forward direction then after some time the door closes when the man passed away.

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From my experience, most automatic door uses BLDC motors. If using BLDC motor, you can reduce the complexity in software by using a driver chipset. In the software you would also want to check the overcurrent condition for obstacles in case the proximity sensor fails. You would want to use closed loop control on the system based on either speed or current or both. There is a good application note that provides an algorithm for a cascade controller from Texas (I don't have the link). For the door controllers that I have worked has adjustments for speed, acc/dec distance, opening times using pots. For your micro you should be able to do all this. The commercial door controller has some inputs for button control like open button or hold open. Before you select your motor, you need to have a specification on what door weight you will be driving so you can choose the gear box ratio and motor size. You would need to be aware of the environment the door is going to be employ. I had major issue when the door and gearbox are cold so plan ahead. In my opinion, the system should have been modelled so you can simulate the environment the door will be in and you can work out the force require to drive the door but anyway it is too late. It you want to model it, there is Turkish master thesis (**broken link removed**) that models a BLDC in gear pulley system with a mass. This is very similar to a door. I hope this help and gives you an idea of commercial door controllers.

use a DC or an AC synchronous motor of sufficient torque, they are simple to control and most probably do need a mcu, a simple hardwired logic can easily do the job.

I have worked on a commercial automatic door software before and also I have used other commercial door controllers as well so I do know how they work. If you actually search for automatic door manufacturers in google, you would mostly find that they use BLDC motors due to its high torque and efficiency to name a few. If this project is just for university and not use in a commercial product use whatever motor to prove your concept or software. The commercial door controllers I have used, they usually have 12:1 or 14:1 gearbox and they use overcurrent detection as a precaution in case if the sensor fails.

yes do you have a schematic to see to help you

Have you tried looking at the appnotes from Microchip. I believe they believe there are several schematics and information about BLDC. Also try Atmel.