Cytron Technical Forum

hi, i need someone to help me..i have transmitter and receiver from RC car to be modified and use for my keyless door lock project...now i want to use motion sensor that will place at the door or wall. when someone with RC car transmitter come near to the motion sensor, it will transmit signal to the transmitter of RC car to automatically closed the switch..but how to use motion sensor connect to remote car to closed the switch that placed at the transmitter ? do you get what i mean?

obviously...... no one get what you mean.

I really dont get the picture of the things you described too.

There are 3 parts: the sensor, the Tx and the Rx, right?

angidain WROTE: when someone with RC car transmitter come near to the motion sensor, it will transmit signal to the transmitter of RC car to automatically closed the switch..

Do you mean that the motion sensor would transmit signal to the Transmitter? But how does the TX receive the signal from the sensor? What does "it" refer to?

You need to describe more on the motion sensor and the RC transmitter.
Is the sensor an active or passive one? What is the output of the sensor?
Is the input of the transmitter using push buttons or joystick? How many channels does it has? Is it using 27MHz or 433MHz etc?

Allen

ops..sorry..and thanks for reply.
yeah, ABSF u right. i mean that the motion sensor would transmit signal to the Transmitter. the input of the transmitter using joystick.. i sketch the picture below to more clearly..in the pic, when someone come nearer to the door, motion sensor detect human body and send the signal to the transmitter of RC car and on automatically so that we don't need to push the toggle. if i not using the sensor, i need to manually use hand to on the transmitter. actually,the idea to on the transmitter is same like automatic lighting project.but, is it suitable if i use motion sensor instead of other sensor in this project or u have another opinion?

It all depends on the sensor you used. If the motion sensor has its own electronics, it would be easier to do. Let's say if an object is detected by the motion sensor, it's output goes High. You can use the o/p to switch on a relay or an opto-coupler. The relay contact can be directly connected to the Tx inputs and trigger sending of signal. Upon receiving the signal by the Rx, it would switch on the Door Lock coil to open the door. You can place the sensor and Tx in the same spot.

Do you have any documents about the RC car remote controls that you'll be using? You should have schematics to show you how to interface to the i/p and o/p. Why not just use the RF modules from cytron as they are well documented and have good examples ?

Allen

ooo i see..very good explanation.thanks.i don't have document for RC car remote control... but, if i use RF modules, i have to program it (write coding) or not because i still new in this electronics study and don't know about the coding..

angidain WROTE:ooo i see..very good explanation.thanks.i don't have document for RC car remote control... but, if i use RF modules, i have to program it (write coding) or not because i still new in this electronics study and don't know about the coding..

So you're doing a MCU-less project. So, forget about the RF modules. Study more on the RC control and if possible try to draw a bit of its circuit on how the joystick is connected. And also the part how the receiver controls the motor in detail. Instead of using a motion sensor, use a push button switch and a 10K resistor. Connect in such a way that when the button is on, it is high(5V) and when the button is not pressed, it is low (0V).

Try to interface the button to the Tx and work until the Rx can respond to the switch. Say a high would on the motor and off would switch off the motor. Then find a motion sensor with built in electronics which gives a "H" when someone is near and "L" when someone is away. Connect the Motion sensor to the Tx and you have a motion sensor controlled motor....Hope you get what I meant.

Replace the motor with your motor-controlled lock mechanism and your project is complete. No programming involved at all.

Allen

You mean the RC transmitter is carried by the person who can access the door and the PIR sensor will transmit signal to activate the RC transmitter when that person approaches the door?