Background Story:

Am a part research scholar & part freelance design engineer, and for one of my project I needed to monitor couple of parameters like Temperature, humidity, light intensity. Using datalogger to perform this task was pretty obvious.

And I don’t have to tell you, how easy it is these days, to build simple datalogger with platform like Arduino.

Earlier, I have built Xbee based simple wireless node for similar applications. But I wanted to do more than that, I wanted to challenge myself.

[I just love to discover new things... Going in to Unknown]

I decided to build WiFi datalogger which will log the data to cloud platform like Thingspeak, Temboo.

I am impressed by its intuitive graphing, simplicity and readiness to export the data and further perform data analysis using MATLAB.

Another reason to choose WiFi, I wanted to try it and ESP8266 was affordable & easy to interface.

I shared this with my research-mates and apparently they were also looking for something like this for monitoring solar panel voltages.

Why?

The main reason to design the WiFio-Mini was 3V3 powered, WiFi-enabled board integrated with low cost and easy to read sensors.

Another reason was to simplify the realization of IoT application and speed-up the prototyping process. I just wanted to remove the complexity and errors involved due to in-compatible Logic levels [3V/5V] with sensors and RF modules. And no need to mention wiring, I have spent hours debugging them.

Why Atmega328P-DIP [With Arduino Core]: Arduino, SIMPLE yet Powerful programming language.

Why ESP-01: One of the widely used and accepted by electronics-enthu community. Simple Serial interface with AT commands. Readily available and low cost.

Why MCP9700: Temperature sensor with 10mV/˚C output. Instantly start monitoring temperature in the surrounding. Industry standard.

Why LDR: Get you started in measuring light intensity in the area. Low cost and easily available.

Why FTDI Header: Most trusted interface for Powering, Flashing sketches and Serial comm./debugging using USB-to-TTL 6-Pin module.

Why GPIO: Inspired by "Real Barebones Arduino" made by Paul Badger over at Modern Device.

Why +3V3: Now a days, Most of the Sensors and Wireless modules support/need 3V operations. Again we need to take care of Logic Level conversion otherwise we end up burning the module.

Technical Details:

MCU: Atmega328P-DIP With Arduino Core.
Wireless Module: ESP-01 [ESP8266].
Sensors: MCP9700 and LDR.
Programming Interface: FTDI Header for Powering, Flashing sketches and Serial communication.
GPIO: Arduino Compatible Digital and Analog I/O.
Power: +3V3 Powered[LM1117 REG.] and Power Jack for External Source[7-12V].
Clock Speed: 8MHz Crystal.

Project Logs

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HW: Done Routing... Now Production
Amar Potdar • 02/01/2017 at 12:07 • 0 comments

Hi Hackers.. It's been long, since the last update. Well, done with routing in last week but could not find time to post project log.. Here it is.
Ok ! There are few little changes.
Ohhh.. Wow.. Look at these 3D shots of WiFio.. Looks cool..
Do let me know your feedback... Thanks All..
Keep Hacking,,, Keep Innovating...
HW : Placement
Amar Potdar • 01/18/2017 at 14:06 • 0 comments
Ok Placement Done..
- Trying to Keep it as simple as I can.
- Paid attention to GPIO for easy access and interface for external peripherals.
- Form Factor as small as possible. Most of them are SMD.
- I guess need to update footprint for DC Barrel Jack, the one I have doesn't matches.
- Also I have noticed that Atmega328P-PU footprint from Atmel EAGLE Library, does not match with the device itself. It's quit ironic. Updated that too with couple of Trial & Error.
HW: Drafting Schema.
Amar Potdar • 01/10/2017 at 09:37 • 0 comments

Block diagram itself is pretty much self explanatory. Drafting schema is not a tough job but, You need to simultaneously take care of the part that you are selecting for - footprint, availability and Pricing.
Undoubtedly, EAGLE is superior CAD tool, no matter How small or Big is your project. I have been using EAGLE for past 2 Years, And I still discover NEW things everyday.
MCU +3V3 Powerd | 8MHz Clocked:
28-PinDIP, for easy Plug-Play and Programming, In case You end-up burning one.
POWER:
LM1117 LDO for +3V3 Regulation and DC Power Jack which allows you to power the board over 9V/12V Power adapter.
GPIO:
As stated in details related board, Inspired from Real Bare Bones.
FTDI Header:
Simple and Easy USB-to-TTL interface for Burning sketches, Serial debugging.
ESP8266[ESP-01]:
+3V3 Powered Low Cost ESP-01 module. Easily available in electronics market or Online ebay/Amazon etc.
MCP9700:
Widely used in industry for Cold Junction compensation and other applications. Output in 10mV/DegC.
LDR:
Light Dependent resistor, See how easy it is to interface. On the next second you can start playing with it, building cool applications.