Hacking a bathroom weighscale for cloud connectivity

Hardware hacker Darrel Tan has a great write-up about his experience with hacking a Chinese-made bathroom scale for cloud connectivity using a Raspberry Pi. His bathroom weighscale has a separate display part that receves the weight measurements from the scale through an infrared link. Darrel hooked up an 38kHz IR receiver to the logic analyzer and placed it near the scale as he was standing on it, so that he could decode the IR bursts. He found that the device used pulse distance coding to encode the data with ~75ms spacing between the consecutive bursts. With further analysis, he was able to figure out how ones and zeros are transmitted and how the weight data is represented in the transmitted stream between the scale and display. After the most difficult part of the hack done, he then hooked up a Vishay TSOP4138 IR receiver to one of the Raspberry Pi’s I/O pins to send the data to the Google Spreadsheet for recording and future plotting.


Hacking a bathroom weighing scale for cloud connectivity

ATtiny85 based mini weather station

This Instructable describes a mini weather station using ATtiny85 and DHT11 sensor. It consists of TX and RX units with a 433MHz RF link to connect them. The TX unit sends temperature and humidity measurements to RF module, which then displays the data on an LCD.

Mini weather station

Mini weather station

In a recent instructable Indigod0g described a mini weather station that works pretty well, using two Arduinos. Maybe not everyone wants to sacrifice 2 Arduinos to get humidity and temperature readings and I commented that it should be possible to do a similar function with two Attiny85′s. I guess talk is easy, so I better put my money where my mouth is.

In fact, if I combine two earlier instructables I wrote:

2-Wire LCD interface for Arduino or Attiny
Receiving and sending data between Attiny85 (Arduino IDE 1.06)
then most of the work is already done. Only need to adapt the software a bit.

I chose for a two wire lcd solution with a shift register, rather than an I2C LCD because on the Attiny the shift register is easier to implement than the I2C bus.

An open source chocometer to measure blood glucose level using IR light

marcelclaro’s entry to HAD Prize 2015 is an open source Chocometer that can measure the glucose level in blood by shining an infrared light source.

Diabetes mellitus is a global problem, in 2013, 382 million people have diabetes worldwide, most with more than 45 years, and global economic cost in 2014 was estimated to be $612 billion USD.The future projections are not encouraging.All forms of diabetes increase the risk of long-term complications (cardiovascular disease, blindness, chronic kidney desease, etc.), however, the complications of diabetes are far less common and less severe in people who have well-managed blood sugar levels.

Today, the diary glucose level check can be done at home, nervertheless, its need a little drop of blood and a chemical reaction strip. So, this check becomes painful and expensive (each strip could cost 0.33 USD). These drawbacks decrease the patient adhesion to treatment.

I propose a glucose meter design based on light absorbance of glucose that already been extensively studied and sucessful applied in laboratory scale.


Open source chocometer

Open source chocometer

Low cost game console using PIC32

Alexander Shabarshin’s XORYA is a low-cost game console using PIC32MX170F256B microcontroller.
XORYA extremely low cost game console that consists of just 1 chip (in its base configuration) – DIP28 integrated circuit PIC32MX170F256B (32-bit MIPS core, 256K flash, 64K data memory) with cost below $5 and a few capacitors and resistors. XORYA is connected to NTSC TV through composite video input and it’s running applications created with help of open source XORLib game library ( http://xorlib.org ) specifically developed for this platform. XORYA may produce a number of black and white video modes (with 640×200 maximum resolution) and (potentially) stereo audio with 15734 Hz sample rate (through PWM). Also with external crystal 14.31818 MHz and 2 more capacitors it may produce color NTSC signal similar to “composite” mode CGA with 16 colors (actually 15, because 2 gray colors look the same) and resolution 160×200. Finally XORYA may receive inputs from up to 10 push buttons (12 if you count RESET and PAUSE). Goal is to get cheap software/hardware platform for “old school” gamedev.

Arduino measures heart beat rate from fingertip

The PIC16F628A based heart rate meter is one of the most popular projects published on Embedded Lab. In this article, I am going to show how to replicate the same project using a simpler platform like Arduino. The Arduino heart rate meter will use Arduino Uno, Easy Pulse Plugin, and 4-digit SPI seven segment LED display module. It computes the heart beat rate by processing the analog pulse signal output from the Easy Pulse Plugin sensor and displays it on the seven segment display module. The heart beat rate is refreshed every ~3 sec.


Heart beat rate meter using Arduino and Easy Pulse Plugin

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