Monthly Archives: March 2016

Arduino – Bluetooth Communication Using HC-05

Arduino, , ,

HC-05 is  a cheap (and easy to use) module that can be used to provide bluetooth connectivity to Arduino.

There are cheap breakout boards available on ebay that can be powered directly by the 5v supply of the Arduino. Below is a picture of such a breakout board. Though my board has “level 3.3v” written but it is working fine on 5v I/O levels. I haven’t run it continuously for days yet but at least a few hours didn’t kill the chip.

HC-05 Bluetooth Module

Jpeg

Some of these boards has one problem - the EN/Key pin, of the board, required for programming the chip (through AT commands) is not connected to the EN/Key pin of the chip. To program the chip on such a board, manual shorting is needed (using some wire) between the EN/Key chip on the board and the chip. In the above picture the EN/Key pin has been marked.

The circuit is pretty simple, connect the VCC to the 5v supply of Arduino, GND to GND, Rx of the module to Tx of Arduino and Tx of the module to Rx of Arduino. For the Rx and Tx software serial ports can be used also.

HC-05 with Arduino

 

The same circuit goes for HM-10 too, which is a BLE device.

ESP 8266 – ESP 01 – Installing Non-OS SDK

Arduino, , ,

After a bit of trial and error got the Non-OS SDK installed. To flash the Non-OS SDK, two sets of files are needed. Below are the download links

 

The flashing tool is attached here for convenience.

 

Now the important part, the mapping (where I was going wrong) and flashing. Please check the documentation for the appropriate mapping. This is for Flash Size & Map: 8Mbit(512KB+512KB)

  • ESP8266_NONOS_SDK_V1.5.2_16_01_29\esp_iot_sdk_v1.5.2\bin\blank.bin    —         0x7e000
  • AT_V0.60_on_ESP8266_NONOS_SDK_V1.5.2_20160203\at\noboot\eagle.flash.bin       —      0x00000
  • ESP8266_NONOS_SDK_V1.5.2_16_01_29\esp_iot_sdk_v1.5.2\bin\esp_init_data_default.bin  —    0xfc000
  • ESP8266_NONOS_SDK_V1.5.2_16_01_29\esp_iot_sdk_v1.5.2\bin\blank.bin           —   0xfe000
  • AT_V0.60_on_ESP8266_NONOS_SDK_V1.5.2_20160203\at\noboot\eagle.irom0text.bin    —     0x40000

 

Non OS SDK Firmware Image Mapping

 

Here is the AT command manual for ESP 8266

 

As on date of writing a Patch has been released which can be downloaded from here or here  —  this patch didn’t work for me. The module is constantly sending some garbage making it unusable. 

USB To RS232 convertor drivers

Miscellaneous

The two most popular USB to RS232 converters are based on either “CH340G” chip or the “PL2303” chip. Below are the drivers (latest as on 02-March-2016) for both.

While purchasing, check if the module has the DTR pin or not. It is not a necessity but will be easy to program the Arduino boards. Without the DTR line the Arduino will have to be RESET manually while uploading the codes to the Arduino.