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
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
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.
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