Motion Sensor (PIR Motion Sensor) HC-SR501
for UPD $ 0.67
I did not find cheaper, and in vain, it was found =)
Such modules have been reviewed at us several times, and after reviewing we found it, decide whether you need this module or not.
And I decided to have a little fun with him
I will not repeat, they did it all before me.
The BISS0001 chip, on which the module is implemented, declares the output level of the TTL standard, which is proportional to the supply voltage in the range from 3v to 5v max.
However, the power range of the module is a fairly wide range of supply voltages, and the LDO stabilizer 7133 is responsible for this.
I was interested in the question of the applicability of this module precisely when powered from a single lithium cell.
Below, measurements of the output control level at an external supply voltage, which is operational for 7133:
These measurements reflect the behavior of the module at the input voltage, when 7133 is already outside the stabilization range:
At the output of the HC-SR501, you can hang up both a field switch and a bipolar one, and their combinations with electromechanical relays, and an optocoupler can also be used.
But I didn’t have all this, but there was a modest handful of DC-DC:
- lm2596 - StepDown - the lower limit of the operating voltage 4.5V;
- sx1308 - StepUp - the lower limit (there was still) the operating voltage of 2.6V;
- MT3608 - StepUp - the lower limit of the operating voltage 2V;
Each of these three has a control input. I did not want to tinker with small things, and selected a relatively large lm2596:
If, I thought, (with the same inputvoltage for both modules) to send a control signal from HC-SR501 to the control fifth electrode lm2596, then in this way, I can control it. So it is, in the data sheet for lm2596 it is indicated that the control voltage can be in the range from 1.3v to 24V.
However, lm2596 is quite gluttonous and there is no sense to use it together with low-voltage battery power.
And here are the possible cases of using HC-SR501 witheconomical MT3608 and even more economical sx1308 on the face. For example, to include a load in which the voltage of one lithium cell for stable operation is low. Modules sx1308 and MT3608, except that StepUp will provide the load and stable voltage.
For example, sending a radio signal to the receiving security guard, by energizing the nine-volt radio button of the wireless apartment call, - as an option =)
A more common use case for the HC-SR501 is to use it with LEDs. Alteration MT3608 in the current driver was found yet.
True, if you use for this special MP3412 driver, then the work will come out more monoconfessional, well, you understand =)
after clicking to this link the download of the reference on BISS0001 will begin;
- to this link - 7133;
- to this link - lm2596;
- to this link - sx1308;
- to this link - MT3608;
- to this link - MP3412.
in a very short video, it can be observed that even at a voltage of 3.4V, the lm2596 still remains operable.