Looking for active-low PIR sensor

Other Hardware Sensors
1

All the sensors I seen are active-high.
Is there a simple cheap PIR sensor that is active-low?
I would like to use it to pull down the reset pin.

EDIT:
The end goal is esp8266 (wemos D1 mini) connected to Ultrasonic Sensor HC-SR04 for accurate presence detection, powered by batteries.

I would like esp8266 to be in deep sleep most of the time. While in deep sleep it can't be woken by input pins, only by pulling RST low.

I would like to use a PIR sensor to wake esp8266, but the one I have is active-high.

I tried to connect PIR output to a relay, but it doesn't output enough current.

What NPN would you recommend to invert PIR's output?

2

You can also add a transistor and pull-up resistor to reverse the signal of an active high one.

3

What board are you using?
You can trigger reset just by using an IO pin to pull reset low as a result of the PIR high.
If you explained what you are trying to accomplish, we can help you do it right.

4

I back @wvmarle
I've some PIR attached to ATTiny13A's. On movement, the mcu wakes up, sends a message via nRF24L01+ and goes to sleep. My problem was that the ATTiny13A did wake up only by low pin. I used an NPN to invert the active HIGH of the PIR to an active LOW (i.e., short the pin to ground).
Works like a charm. Powered by 2 AAA, the setup is lasting forever (read: running for months).

Best

5

Thank you everyone for the answers.

The end goal is esp8266 (wemos D1 mini) connected to Ultrasonic Sensor HC-SR04 for accurate presence detection, powered by batteries.

I would like esp8266 to be in deep sleep most of the time. While in deep sleep it can't be woken by input pins, only by pulling RST low.

I would like to use a PIR sensor to wake esp8266, but the one I have is active-high.

I tried to connect PIR output to a relay, but it doesn't output enough current.

What NPN would you recommend to invert PIR's output?

6

Just about any cheap small signal transistor will do.

7

Any small NPN transistor will do (BC547/48 2N3904 etc.).
No resistors needed.
Base to PIR output.
Emitter to ground.
Collector to reset pin (I assume it has a pull up resistor).
Leo..