Hacked Gadgets Forum

September 4, 2014

HLK-RM04 Serial to WiFi Module

at 10:45 pm. Filed under Educational, Electronic Hacks

HLK-RM04 Serial to WiFi Module


If you are looking to add some WiFi connectivity to your next project the HLK-RM04 Serial to WiFi Module might be just the thing if you want to go wireless. The $10 HLK-RM04  module handles all of the WiFi overhead so your microcontroller project can simply send serial data to it using the TX and RX pins. RAYSHOBBY.NET has a great tutorial including code to get you started with this module.

Via: Dangerous Prototypes

“The chip (RT5350F) is a 360MHz MIPS core with built-in WiFi support. The module is quite powerful — at factory default settings it functions as a normal WiFi router. Now, in order to get it to talk to a microcontroller like Arduino, I need to use its Serial-to-WiFi capability. What is that? Well it means using the serial (TX/RX) interface to send and receive Ethernet buffers, and similarly using serial to send commands to the module and query or change its current status. This is quite convenient because first, it only takes two wires (TX/RX) of the microcontroller to talk to the module, second, it moves WiFI-related tasks to the module allowing the Arduino code to be very much light-weighted. “


July 28, 2014

Portable Device for Measuring Hydration and Body Fat

at 9:38 am. Filed under Cool Gadgets, DIY Hacks, Educational, Electronic Hacks



Cornell ECE 5030 students Uma Mohan, Sarvesh Sukhatme and Priyanka Venkatesh have designed a Portable Device for Measuring Hydration and Body Fat. The project passes a small current through the body to measure the amount of hydration in the person. A 940 nm LED is used to detect the amount of fat the person has by shining it through a part of the body, the amount of light that passes through allows them to calculate the body fat of the person.

“We used a LM358 Opamp to make a voltage dependent constant current source. Setting the resistor connected to pin2 as 200 ohms sets the current as the (voltage magnitude/200) A.  The voltage source used was a square wave with magnitude 0.2V and frequency 2Hz.”


June 26, 2014


at 11:30 pm. Filed under Educational


Pyroelectro has just started a course to teach you how to use FPGA and CPLD devices. If you are currently using microcontrollers this course will give you the skills to move to the next level. There are 10 lessons in the course which will start you at hello world and quickly progress into some very usable topics. The video above is from the first of 10 course videos, the other 9 courses will be released one per week.

If FPGA and CPLD devices are a bit over you head you can start with basic electronics and digital electronics first.

Thanks for the tip Chris.

“Here’s a short overview of the course:

This course is meant to create a pathway into learning about FPGA and CPLD electronics, for people who are scared of the code, tools and general trickery that usually comes with it. A hands-on approach is taken in this course through a combination of lecture and experimentation to teach you about the different features of both the development tools and languages used in the world of FPGA.

Additionally, visuals are used throughout lectures like step-by-step schematic building and line-by-line code explanations so that everything gets explained.

Signups @ Ureddit: http://ureddit.com/class/106959/ Course Page: http://www.pyroelectro.com/edu/fpga/



June 4, 2014

Submersible Thruster

at 8:55 pm. Filed under DIY Hacks, Educational, Electronic Hacks

Submersible Thruster


If you are looking to design some underwater propulsion Dane from Transistor Man has completed a well documented Submersible Thruster build to get some pointers from.

The goal here is to design a submersible motor assembly that is able to accomplish the following:

  • Able to operate, submersed, up to 1 meter underwater while not transfering more than 10ml of coolant into the surrounding water per hour (not leaky)
  • Capable of delivering >5kw of motive thrust, when driven at 40v from a sensorless 3 phase motor drive.
  • Utilize a clear housing assembly to allow for easy-to-observe internal failures or leaks
  • Actively aid in cooling the motor assembly, using condutive heat transfer
  • Maintain a rotating shaft seal while operating up to 2k RPM. 
  • Design using easy to assemble, easy to reproduce components (ex: off the shelf bearing & shaft seal assemblies, waterjet aluminum)
  • Utilize a propeller designed to operate at 2k RPM without significant cavitation effects at speed*


Submersible Thruster Static Test 2 from Dane Kouttron on Vimeo.

March 17, 2014

Bypass Capacitor Tutorial

at 11:12 pm. Filed under Educational

bypass capacitor


We all use Bypass Capacitors in our designs but what size do you normally pick and why? Does location of the bypass capacitor matter? Should you use multiple values of capacitors? Chances are some of these questions are not obvious and might enhance your future designs if you know the answers. Electro Labs has a great article that solves of these questions in their Bypass Capacitor Tutorial.


January 15, 2014

How a 4 Layer PCB is Made

at 6:19 am. Filed under Complex Hacks, Educational


When you send off your Gerber files to have your latest board made you will be shipped some shiny new board in a few weeks. The process of creating the boards is very time consuming, the video above goes through the many steps of how a 4 layer PCB is created. Most boards are 2 layer but it is interesting to see how the inner layers of the 4 layer boards are created. It is hard to believe that our boards can be processed through this many steps and be flawless when they are completed since a small mistake on any of these steps would have a good change of damaging the entire thing.

January 3, 2014

Gesture Based Security Lock Project

at 4:54 am. Filed under DIY Hacks, Educational, Electronic Hacks

Gesture Based Security Lock Project


Instead of using keys and codes for security this device that Ankur Thakkar, Darshan Shah and Saisrinivasan Mohankumar built as part of their ece4760 Final Project uses gestures to grant access. The system uses IR sensors to determine the movement of a persons hand within the detection area, after you train the unlock pattern you can simply repeat the pattern to activate the device. I think a small miniature version of this that can detect a finger instead of a full hand would be a great replacement of a typical keypad and would probably be able to retain a similar form factor. Nice thing about this technology is that it is contact free, these days no one likes touching things like keypads that thousands of others have potentially used before them.

“The IR proximity sensors gave us an analog voltage proportional to the distance of the sensor from a flat object placed in the user’s hand for drawing the patterns. The analog voltage from each of the sensor is given to the ATMega1284P, which utilizes the internal Analog to Digital Converter, to convert this analog voltage to digital signal which can be utilized by the microcontroller for further processing.”


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