PIR Motion Sensor Input Voltage Range

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mphatak
 
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PIR Motion Sensor Input Voltage Range

Post by mphatak »

Hi

I just bought the Adafruit PIR motion sensor:-

https://learn.adafruit.com/pir-passive- ... on-sensor/

The product page states that the input voltage is 5-12Vdc "for most modules", but I wanted to check the exact spec.

I see that the 3.3Vdc regulator is a Holtek HT7133-1 which in fact accepts up to 30V:-

https://www.holtek.com/documents/10179/ ... -1v250.pdf

Can you confirm if this is the right part?

Thx

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adafruit_support_bill
 
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Re: PIR Motion Sensor Input Voltage Range

Post by adafruit_support_bill »

The regulator may be able to accept up to 30v input. But the current it can deliver decreases at higher voltages.

Linear regulators act like 'smart' resistors and burn off the extra voltage as heat. The higher you go, the more heat it needs to dissipate. At 30V, the Holtek HT7133-1 would need to dissipate 89% of the input power.

I'd stick with the 12v recommendation.

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mphatak
 
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Re: PIR Motion Sensor Input Voltage Range

Post by mphatak »

Thanks for your reply.

I am not intending to run the sensor at 30V.

I just wanted to know the maximum voltage the sensor would accept.

Our system currently runs at 12V but could reach slightly higher values under certain circumstances, hence my question.

Thanks again.!

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adafruit_support_bill
 
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Re: PIR Motion Sensor Input Voltage Range

Post by adafruit_support_bill »

Slightly higher at times is probably not a problem. The main issue is heat buildup. If there will be extended periods of elevated voltage you should ensure that there is adequate air circulation around the sensor.

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mphatak
 
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Re: PIR Motion Sensor Input Voltage Range

Post by mphatak »

Thank you

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