Infrared PIR Motion Sensor without an Arduino

[Pruitt]

Hi
I had an idea to promote a friend's tea and coffee business with a desktop rolling info page, but can't come up with a layout for the electronics without an Arduino. The reason I don't want the Arduino is that there isn't any room in the unit for it. Also, the cost of an Arduino is much too high for this project.

I wanted to put a horizontal rolling glass cylinder on a plinth and have it start turning automatically when triggered by an infrared PIR motion sensor placed on the front of the plinth. So when someone walks past it starts the continuous rotation servo motor, which in turn starts the glass cylinder rotating. This would also make the coloured LEDs light up from underneath, giving an illuminated effect. The main problem with this setup is the PIR has a signal terminal on it which triggers the servo and the LEDs to start. I expect this is why you see an Arduino being used in this configuration.

Is there a circuit diagram out there that does the above without the use of an Ardunio?

Thanks a lot.

Michael.




Is there a cuic

 

[danadak]

You can get processors in the area of 10 cents if thats the prime limiter. Check
hackaday, youtube, and eevblog sites for discussions on low end processors.

Design sounds like a natural for a low end processor.

This a one off design or a volume design ?

 

[Les Jones]

Assuming that the glass cylinder is required to rotate exactly 1 revolution it can be done without using any microcontroller.
Have a disk attached to the cylinder with a notch cut in the edge. Have micro switch with the roller resting on the edge of the disk so it is actuated exept when the roller drops into the notch. The normally open contact of the micro switch would be connected between the motor and its power supply. A contact on the PIR would be connected in parallel the the microswitch contacts. When the PIR was triggered it would give pulse long enough for the motor to start rotating so that the microswitc roller was no longer in the notch. the motor would continue to rotate until the roller dropped into the notch. You may need to change the length of the pulse from the PIR so that it was long enough for the microswitch roller to move out of the notch but less than the time required for a revolution of the cylinder.

Les,

 

[Pruitt]

Hi Les
I want the cylinder to rotate ever so slowly so people can read the engraved writing on it. I'm not sure what time it would take for one revolution, but I would expect it would be something between 15 and 20 seconds. The disc with the notch in it is a good idea, one I hadn't thought of.

Would it be asking too much of you to do a quick diagram/sketch so I could better understand your layout?

Thank for the reply.

Michael.

 

[Les Jones]

Here is the sketch.

The contact on the micro switch should be open when the the micro switch lever is aligned with the notch.
You just need to select a motor with a suitable speed. You could also use a stepper motor and driver and control the speed by changing the frequency of the step pulses.
Altenatives tothe micro switch would be a slotted opto sensor or a magnet and reed switch instead of the notch.
Depending on the output pulse from the PIR you man need to shorten oe lengthen the pulse to strat the motor moving from the stopping position. yaou could use an NE555 to do this.

Les.



Les.