If I make connections like you see in picture below, will it work? Will I damage ESP or HC-SR04?

As I know;

HC-SR04 (VCC) -> 5V

ESP8266 (VCC) -> 3.6V

ESP8266 (RX/TX) -> has 5V tolerance ?

I have not taken into account the currents that will each pin draw. So, is everything OK?

I'm not good at this stuff, so I'll appreciate it if you guys give me advice


Circuit Diagram

Most of you suggest to use voltage regulator instead of external AA batteries. However, I have already ordered one but it takes too much time (nearly week) to get, due to delivery-shipping issues. So, I want to work on the coding part of my project.

  • The voltage regulator would be used in conjunction with not instead of the batteries. Regulators do not supply power by themselves. Oct 19, 2015 at 15:48
  • Three freshly charged NiMH cells can easily exceed 3.6v, and if someone substitutes alkalines, potentially by a lot. Nov 21, 2015 at 23:18

2 Answers 2

  1. GND seems dangling.
  2. If you are going to use multiple power sources, make sure that all the minus/GND are connected together.
  3. Whether the ESP8266 can use 5V or not should be checked against the actual unit you have. There are many variants and some might be more tolerant than others.
  4. You do not show the power source for 5V - what is it?
  5. By just typing on google HC-SR04 5V, you get a link to the manual, which has a section "4.0 PRODUCT SPECIFICATION AND LIMITATIONS": Min:4.5V Typ:5V Max:5.5V. You should at least give it a try and report your findings, asking for clarifications, if you need any, rather than just ask here for something that google can provide.
  • 1- I didn't get what you mean by saying 'dangling' 2- I noticed that and connected them together. 3- I searched and checked it has 5 V tolerance. 4- No reason for connecting 5 V to board, I just made it if I need later. I'll try now and let you notify the latest results. I hope I won't make something damage and useless. thx for suggestions Oct 18, 2015 at 12:27

When you get the wiring sorted out, remove the batteries and plug in the USB, that should power it up and allow you to start writing your code.

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