ESP8266 IoT Low-cost WiFi Repeater

Left: NodeMCU EPS-12E, right: ESP-01S with CH340 adapter

The ESP8266, especially the ESP-01S board can be used as a low-cost WiFi repeater. Add a CH340 USB serial port adapter(RM6.50) for the ESP-01S (RM14.90) and it is still only RM21.40.

A WiFi Range Extender like the D-Link DMG-112A can be bought for RM45, but the ESP8266 is especially cost-effective if the WiFi repeater software can be included in your ESP8266 IoT device. Such an IoT device can be meshed with others to form a WiFi net, extending the IoT cloud's reach.

D-Link DMG-112A WiFi Range Extender is only RM45

Hasten then to Martin Ger's superlative site.

I used Expressive's esptool.py successfully with all three of my programmers, the CH340 ESP-01S adapter, my makeshift ESP-01S programmer, as well as the built-in programmer in the NodeMCU ESP-12E Lua.

I had already upgraded my Slackware 14.2's python to version 2.7.11. This made installing esptools.py easy. Just do:

# pip install esptool

Download's Martin Ger's firmware/0x00000.bin and firmware/0x10000.bin from here. I started with the NodeMCU ESP-12E:

$esptool.py --port /dev/ttyUSB0 write_flash -fs 4MB -ff 80m -fm dio 0x00000 ./0x00000.bin 0x10000 ./0x10000.bin
esptool.py v2.4.1
Serial port /dev/ttyUSB0
Connecting....
Detecting chip type... ESP8266
Chip is ESP8266EX
Features: WiFi
MAC: 60:01:94:70:54:1b
Uploading stub...
Running stub...
Stub running...
Configuring flash size...
Flash params set to 0x024f
Compressed 37072 bytes to 25809...
Wrote 37072 bytes (25809 compressed) at 0x00000000 in 2.3 seconds (effective 126
.9 kbit/s)...
Hash of data verified.
Compressed 262916 bytes to 178828...
Wrote 262916 bytes (178828 compressed) at 0x00010000 in 15.8 seconds (effective
133.0 kbit/s)...
Hash of data verified.

Leaving...
Hard resetting via RTS pin...

And that was it; it reset the ESP-12E and the firmware started without fuss.

My ESP-01S took a lot longer as the programming baud rate is only 9600. Remember to put the ESP-01S into 'program' mode manually:

$esptool.py --baud 9600 --port /dev/ttyUSB1 write_flash -fs 4MB -ff 80m -fm dio 0x00000 ./0x00000.bin 0x10000 ./0x10000.bin

esptool.py v2.4.1

Serial port /dev/ttyUSB1

Connecting....

Detecting chip type... ESP8266

Chip is ESP8266EX

Features: WiFi

MAC: ec:fa:bc:1c:c6:0d

Uploading stub...

Running stub...

Stub running...

Configuring flash size...

Flash params set to 0x024f

Compressed 38048 bytes to 26400...

Wrote 38048 bytes (26400 compressed) at 0x00000000 in 27.8 seconds (effective 11

.0 kbit/s)...

Hash of data verified.

Compressed 265860 bytes to 181152...

Wrote 265860 bytes (181152 compressed) at 0x00010000 in 190.5 seconds (effective

 11.2 kbit/s)...

Hash of data verified.

Leaving...

Hard resetting via RTS pin...

Power-cycle (or reset) the ESP-01S to start the firmware running.

I had no problems accessing the WiFi repeater Access Point. It is a little slow, and my test youtube video stuttered a bit, but it played to completion. For IoT use, especially the built-in MQTT, it should be sufficient.

Happy Trails.