Tech Diary

ESP-01 is a simple ESP8266 module which can be purchased cheaply from Aliexpress. At one of promotion, I purchased an ESP-01 for just S$1.97. That's very cheap for a wifi enabled microcontroller. An ESP-01 can be a WIFI bridge for non-connected microcontroller such as Arduino UNO, Mega, Nano etc. Communication between the microcontroller can be done using the serial link between them. I have written a post on this using ESP-Link to connect to an Arduino Pro Mini. Together with the client library provided, the Pro Mini can easily transfer sensor data via MQTT. http://iotdiary.blogspot.sg/2017/09/using-esp-link-transparent-bridge.html For the most part, once the firmware is in place, normally I will use OTA to update. Sometimes, I wanted to reuse the same controller for another firmware and I have rewired up the controller for reflashing. This makes it very inconvenient to use. Recently, I bought a USB ESP-01 adapter thinking that my problem is solved. When I received it and r

UDOO Quad is a maker SBC board from UDOO . It has a built-in Arduino microcontroller and can run Linux on the SBC. On the web, most of the Google IoT Core samples have been focused using Mongoose OS and I have written a post on " Journey into Google Cloud IoT Core with ESP8266 and Mongoose OS ". Recently, Google releases code samples which make the initial handshaking with Cloud IoTCore simpler.  For UDOO, the tedious part is to get all supporting tools to work with a particular version of Linux Distribution. UDOO supports a few Linux distributions (Ubuntu, Debian and others). I have installed Ubuntu and the current version supported by UDOO is 14.04 LTS. For this demo, I wanted to work on Python 3.5 and I have compiled the Python from source. This is step may not be necessary if you use the version that is installed (Python 3.4). The idea for this project is to read the temperature and humidity reading from UDOO Arduino side, transfer the data to Linux side and forward t

I have found this interesting board selling on Aliexpress website. It is an Arduino Mega 2650 with a built-in ESP8266 which allows the Mega to connect to wifi. This board has cut down a lot of wiring and bring out interesting possibilities. One of this is to connect up both the microcontrollers using ESP-link firmware. I have an earlier blog post  that described how to wire up an ESP-01 and Arduino Pro Mini. One of the tricky parts in this setup is the sequence of flashing the ESP firmware. Flashing the onboard ESP8266 requires some setting changes to the dip switches. The following are the sequences which I get both the microcontrollers to talk to each other. Set the jumper 5,6,7 to ON and the rest OFF. This will set the ESP to update mode. I am using version 3.0.14  and flashed the ESP using the following parameters: esptool --port com26 --baud 230400 write_flash -fm dio -fs 4MB -ff 80m 0x0 boot_v1.6.bin 0x1000 user1.bin 0x3fc000 esp_init_data_default.bin 0x3fe0