Arduino Power-down Mode With Accelerometer, Compass and Pressure Sensor

Arduino Power-down Mode With Accelerometer, Compass and Pressure Sensor

Introduction

Last article, I wrote about how to use our own homemade Arduino Pro Mini bare bones along with an OLED display and how to make both of them consume as little power as possible. In fact, we managed to achieve a small 1.1 uA current with both of them sleeping. Also in our circuit there were a PCF8563 real-time clock module and one AT24C64 EEPROM memory. Now, to proceed with our smartwatch project we need to add sensors, such as an accelerometer, compass and pressure sensor. This article is about how to add them, read the variables and keep saving power.

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OLED Display and Arduino With Power-Save Mode

OLED Display and Arduino With Power-Save Mode

On the previous article I wrote about how to use the real-time clock module with the EEPROM non-volatile memory. Now it is time to get something working that resembles a watch. Make something that matters. How about adding a display? Last post it was possible to achieve a power consumption of only 16 uA (improved) 0.7uA on the smartwatch prototype. Now we can see how much power the watch will consume. In this case, it is an application that needs to consume the smallest current possible but also needs a display, then one can use a OLED display, which is the abbreviation of “Organic Light-Emitting Diode”, which is a much more economic display in terms of current than the regular LED displays. An overview about OLEDs, first.

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GSM Shield Home Alarm

arduino gsm shield alarm movement pir sensor keypadThe other day my father and I were discussing about the problems of living in a third world country. Because of the social inequality, there is little security on the streets. Also one major problem is that no one is secure, even the 1% richer, because there are know cases of robbers getting inside homes even on private neighbourhoods. We ended up thinking about putting a home security system  in our house. The problem is those are very expensive and, in general, they just ring an alarm to scare potential thieves, but they don’t actually warn you in real-time that your house is being invaded. A complete system would be even more expensive. So I got the idea to make my own Arduino based home alarm. I just had to buy a GSM shield for the Arduino Uno, because all other parts I already had.

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