Hi all,

I'm a noob to electronics (woodworker hobbyist but comfortable with light electrical work) and I could really use some help with an under-bed lighting I'm making for my elderly parents. In a nutshell, I want to use two PIR sensors and two LED strip lights--one set for each side of the bed--that turn on when the respective PIR sensor is tripped. I'd prefer to have one power source that powers both. Here's the list of materials I have:

- PIR sensors: http://www.frys.com/product/8555259...pFi-7yKzjiKVHdBAj84TwnuO-CuxxTyEaAspREALw_wcB
- LED strips: http://www.ebay.com/itm/1-5-10-20m-...hash=item5b368bb96c:m:mRHgzXkYRcL5VBJbVibSHpA
- Power supply: http://www.ebay.com/itm/12V-5A-60W-...hash=item33c13db0b5:m:mrxhLeCvA-58rHwLhMKo5NQ
- Power jacks: http://www.ebay.com/itm/10Pcs-5-5x2...756911?hash=item25d3c5f92f:g:qXkAAOSwls5Y6x~y

Do I need any additional materials like a mosfet?

If you could please help me to understand how to wire this together, I'd appreciate it. I'm *just* learning schematics so if you have diagram suggestions please feel free to draw them like I'm a 4-year old. Thanks very much!
~David

 

Hi all,

I'm a noob to electronics (woodworker hobbyist but comfortable with light electrical work) and I could really use some help with an under-bed lighting I'm making for my elderly parents. In a nutshell, I want to use two PIR sensors and two LED strip lights--one set for each side of the bed--that turn on when the respective PIR sensor is tripped. I'd prefer to have one power source that powers both. Here's the list of materials I have:

- PIR sensors: http://www.frys.com/product/8555259...pFi-7yKzjiKVHdBAj84TwnuO-CuxxTyEaAspREALw_wcB
- LED strips: http://www.ebay.com/itm/1-5-10-20m-...hash=item5b368bb96c:m:mRHgzXkYRcL5VBJbVibSHpA
- Power supply: http://www.ebay.com/itm/12V-5A-60W-...hash=item33c13db0b5:m:mrxhLeCvA-58rHwLhMKo5NQ
- Power jacks: http://www.ebay.com/itm/10Pcs-5-5x2...756911?hash=item25d3c5f92f:g:qXkAAOSwls5Y6x~y

Do I need any additional materials like a mosfet?

If you could please help me to understand how to wire this together, I'd appreciate it. I'm *just* learning schematics so if you have diagram suggestions please feel free to draw them like I'm a 4-year old. Thanks very much!
~David

The only PIR devices that I have seen work on 120 volts AC, and thus would not function correctly in your application. I did not investigate the links to those you have selected, so I don't know about them. IF the PIR sensors provide a set of contacts the they should work quite well in this application. But given that this is for under a bed that people are sleeping in you need to be certain that everything is done to avoid sparks and heat and setting things on fire. Metal boxes for the electronics is a good idea.

 

The PIR sensor that you link to does not give much information about it. I suspect that the output is just a short pulse which would need to trigger a timer to control how long the lights stay on after they were triggered. There are many adverts on ebay for PIR modules. Some adverts such as this one give detailed information, others like yours tell you almost nothing. This one would require a logic level N channel mosfet to drive the LED strips. As you are new to electronics it may be better to get a ready made unit such as this. I have used security system PIRs for this sort of application in the past as they normally work from 12 volts. (These only give a short pulse out in the form of opening a set of contacts.) One thing you need to consider is the positioning of the sensor. I single sensor mounted on the side of the bed pointing out will probably not give very reliable triggering. Mounting the sensor near the bottom of the bed with it's field of view along the side of the bed would probably work better.

Les.

 

The PIR sensor that you link to does not give much information about it. I suspect that the output is just a short pulse which would need to trigger a timer to control how long the lights stay on after they were triggered. There are many adverts on ebay for PIR modules. Some adverts such as this one give detailed information, others like yours tell you almost nothing. This one would require a logic level N channel mosfet to drive the LED strips. As you are new to electronics it may be better to get a ready made unit such as this. I have used security system PIRs for this sort of application in the past as they normally work from 12 volts. (These only give a short pulse out in the form of opening a set of contacts.) One thing you need to consider is the positioning of the sensor. I single sensor mounted on the side of the bed pointing out will probably not give very reliable triggering. Mounting the sensor near the bottom of the bed with it's field of view along the side of the bed would probably work better.

Les.

Les makes a number of good points. A totally different approach that would work well but not be cheap is to use one of the occupancy sensor devices that mount in a single-wide electrical box to control the power supply. The benefit of this is that the occupancy sensor includes the power switching and also a timer, so that the LEDs will stay on after the person passes by. The ones that I have used the timer can set for up to thirty minutes. Also, the whole setup is already in a very safe package, and if you use a metal electrical box the whole thing is quite safe. But those items may not be easily available, depending on what part of the world you are in. And I have observed that posts here do come from all parts of the world, which is interesting.