# Hc05 Arduino Nano **URL:** \ **Category:** General Guidance\ **Created:** [June 26, 2025, 4:43pm UTC](https://forum.arduino.cc/t/hc05-arduino-nano/1391971 "2025-06-26T16:43:30Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![xyclon](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/xyclon/32/1224529_2.png) [@xyclon](https://forum.arduino.cc/u/xyclon)\ **Post date:** [June 26, 2025, 4:43pm UTC](https://forum.arduino.cc/t/hc05-arduino-nano/1391971/1 "2025-06-26T16:43:30Z")
Hello guys, I have a project where I need to send data to my phone using an Arduino Nano and an HC-05 module. However, sometimes the HC-05 sends data, and sometimes it doesn’t. What could be the reason for this? Can you help me? ---
**Author:** ![sonofcy](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/sonofcy/32/1283617_2.png) [@sonofcy](https://forum.arduino.cc/u/sonofcy)\ **Post date:** [June 26, 2025, 4:48pm UTC](https://forum.arduino.cc/t/hc05-arduino-nano/1391971/2 "2025-06-26T16:48:52Z")
How do you know? ---
**Author:** ![xyclon](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/xyclon/32/1224529_2.png) [@xyclon](https://forum.arduino.cc/u/xyclon)\ **Post date:** [June 26, 2025, 4:52pm UTC](https://forum.arduino.cc/t/hc05-arduino-nano/1391971/3 "2025-06-26T16:52:18Z")
The project also includes an OLED display. This display shows the data that needs to be sent via Bluetooth. As I mentioned, sometimes bluetooth sends the data, but sometimes it doesn't. ---
**Author:** ![Nick\_Pyner](https://avatars.discourse-cdn.com/v4/letter/n/e8c25b/32.png) [@Nick\_Pyner](https://forum.arduino.cc/u/Nick_Pyner)\ **Post date:** [June 26, 2025, 5:01pm UTC](https://forum.arduino.cc/t/hc05-arduino-nano/1391971/4 "2025-06-26T17:01:43Z")
In the absence of better information, your problem could be simply inadequate power. So how are you powering it? There is nothing to suggest there is anything wrong with the code or wiring - unless the latter is sloppy. ---
**Author:** ![xyclon](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/xyclon/32/1224529_2.png) [@xyclon](https://forum.arduino.cc/u/xyclon)\ **Post date:** [June 26, 2025, 5:22pm UTC](https://forum.arduino.cc/t/hc05-arduino-nano/1391971/5 "2025-06-26T17:22:24Z")
We’re powering the system with a 3.7V 1000mAh Li-Po battery, and we’re using an XL6009 voltage regulator to step up and stabilize the voltage for the rest of the components. So far, we haven't noticed any major voltage drops. ---
**Author:** ![xfpd](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/xfpd/32/1120236_2.png) [@xfpd](https://forum.arduino.cc/u/xfpd)\ **Post date:** [June 26, 2025, 5:30pm UTC](https://forum.arduino.cc/t/hc05-arduino-nano/1391971/6 "2025-06-26T17:30:21Z")
While lacking a console (serial monitor), test and display the BT connection status (HC05 to phone), like "+" for present and "-" for absent, and display this on the OLED. ---
**Author:** ![sonofcy](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/sonofcy/32/1283617_2.png) [@sonofcy](https://forum.arduino.cc/u/sonofcy)\ **Post date:** [June 26, 2025, 5:47pm UTC](https://forum.arduino.cc/t/hc05-arduino-nano/1391971/7 "2025-06-26T17:47:33Z")
I think we need to see all the code in code tags, and any log data also in code tags plus a wiring diagram. A photo of a hand drawn diagram is ok. ---
**Author:** ![cattledog](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/cattledog/32/217816_2.png) [@cattledog](https://forum.arduino.cc/u/cattledog)\ **Post date:** [June 26, 2025, 6:13pm UTC](https://forum.arduino.cc/t/hc05-arduino-nano/1391971/8 "2025-06-26T18:13:25Z")
> [@xyclon](#): > > data to my phone What app are you using on the phone? ---
**Author:** ![GolamMostafa](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/golammostafa/32/239011_2.png) [@GolamMostafa](https://forum.arduino.cc/u/GolamMostafa)\ **Post date:** [June 26, 2025, 6:29pm UTC](https://forum.arduino.cc/t/hc05-arduino-nano/1391971/9 "2025-06-26T18:29:39Z")
Check that your BT wiring is similar to Fig-1: ![hc05-UNO](https://europe1.discourse-cdn.com/arduino/original/4X/d/6/d/d6d90ac65b8756f989d000d4d3c41d5a36041727.png) Figure-1: ---
**Author:** ![Nick\_Pyner](https://avatars.discourse-cdn.com/v4/letter/n/e8c25b/32.png) [@Nick\_Pyner](https://forum.arduino.cc/u/Nick_Pyner)\ **Post date:** [June 27, 2025, 12:10am UTC](https://forum.arduino.cc/t/hc05-arduino-nano/1391971/10 "2025-06-27T00:10:38Z")
> [@xyclon](#): > > So far, we haven't noticed any major voltage drops. The fact that your problem is intermittent rather suggests it is down to a minor voltage drop. Your vague description also suggests you might be running Bluetooth directly off lipo, which is clearly only just sufficient. If the above is correct, and as the 6009 probably has the capacity, you might consider running Bluetooth that way, i.e. off 5v, like everybody else does. ---
**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\ **Post date:** [December 24, 2025, 12:10am UTC](https://forum.arduino.cc/t/hc05-arduino-nano/1391971/11 "2025-12-24T00:10:48Z")
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