Hi, It has been so long I am not talking about arduino. I have a project with arduino and I will expose it yet. But, one part of the project (programmes) is to have a log file in SD card named by date. Something like YYYYMMDD.CSV file.

Basically, I used RTClib.h library because date/time syncronisiation is very simple. To create file name based on date, we need to put every digit in file name charactor from integer values. So, we need to know about % (modulo) and / (divider) algorithm. Some of us maybe not very familiar with modulo. You can read about module in here.

And also, we must understand SD.h is only allow 12 characters, something like 8 characters for file name, . , and 3 characters for the extention file name. (YYYYMMDD.CVS) Total 12. More than that is not acceptable.


I got a temperature sensor called LM35. The package similar to common transistor and slightly doubt on its look. I bought a few weeks ago from Ebay. Once i got it, it was hard to handle it. The pins were really fragile and thought it was better for me to buy the sensor that already soldered on a PCB. But, without the PCB, the cost is very cheap. Finally, I ended up to continue this lab with simple sensor connection and I think I never use the sensor in the next project after all.


WALL-E in development.

Few months back, in my mind, I needed to build up a cat/dog repellent based on Arduino circuit. But, at the same time, I needed a sensor to detect an object exists in front of the device. I bought an ultrasonic sensor suitable for arduino. There are two kind of ultrasonic sensor with different circuit pin. 3 pins or 4 pins. I got HC-SR04 which is having 4 pins, Vcc, Trig, Echo and GND.

And the most important thing was, I needed to learn how to write a program for the sensor. To learn how to write a testing program I found this site, http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1272177425


Dengan menggunakan Arduino + Ultrasonic module, mungkin kita boleh buat radar. Tetapi bagaimana untuk membuat 360 darjah pusingan?

Sebelum ini, saya ada menunjukan eksperimen pertama saya membuat LED berkelip menggunakan Arduino.