Soil moisture (humidity) measure system

   A nice and interesting gadget for Arduino board is soil moisture sensor, who can buy from Sparkfun,

ebay, aliexpress, banggood, etc.

   For last version schematic is:

   This version has 2 outputs, one analogical and one digial. If value of humidity is bigger than reference led D2 is on:

   I use a LCD1602 with i2c interface with a Arduino Mega (ADK) board and my test schematic is:

   I write a sketch named lcd1602_i2c_soilhumidity_ver0.ino put on my github channel:

   If sensor has probe in the air:

and if I put wet fingers:

  I made a small movie named soil humidity measure system on alphanumerical lcd display

and than I put a clone Arduino Uno board:

and made new movie, named soil humidity measure system on alphanumerical lcd display (2)

   Next step was to I use a Arduino Leonardo:

and a movie named soil humidity measure system on alphanumerical lcd display (3)

Arduino on VGA display

original article in Roumanian language

   I search for info about how can use Arduino as VGA tester or video card.
   First credible article is Simple VGA/Video adapter who can use 8-bit AVR MCU like ATmega8, 328, etc:

   Article is writted by Maxx Ibragmov and a their montage is:

   On TV, resolution is 20 rows with 38 character each:

and on VGA monotor, resolution is 20 rows with 20 characters each:

  I wanted fast result and try other adapter montage (without diodes):

   First test was with info from article Arduino generated VGA (color) signal - Complete!

who use this schematic:

   I use Arduino IDE 1.0.3 and my test image is:

NOTE (27.09.2017): Now site is "down", so you can download usefull files from https://github.com/LaboratorioDeGaragem/VGA-com-Arduino !

   I try to reproduce a more complex image like in article Arduino generated VGA (color) signal - Complete! (other site, same author):

but image is not clean.. and I jump to other material find in article Basic Arduino VGA:

   I use same Arduino IDE 1.0.3, but my test image is not same in original article:

   Next step was to reproduce expermiments from Nick Gammon with VGA

   First is a black/white VGA video card for 30 rows with 20 alphanumerical characters each. Schematic is simple:

   This VGA video card use i2c protocol for comunicate with other Arduino board, but results are very poor on transmision data (author say: unfortunately incoming data (can) make  the display "glitch"). I made a movie (explanations are in Romanian language, but you may can understund what I want to say):

   Next test was with moving colour test image on VGA display, using this schematic:

and a image is:

   I made a movie with image on VGA (saame, with explanations are in Romanian language):

   Next step was to test VGAX library writted by Sandro Maffioda after Nick Gammon info.. on display resolution is 120x60px with 4 colours.

   Schematic is simple:

   You can made some combination:

1) red & green made: black, red, green & yellow:

2) red & blue made: black, red, blue, purple:

3) green & blue made: black, green, blue, cyan:

4) red & cyan (green + blue) made: black, red, cyan, white:

5) blue & yellow (red + green) made: black, yellow, blue, white:

6) green & purple (red + blue) made: black, green, purple, white:

   I made some movies for understund more easy:

   

Arduino alarm system with delay (2)

original material

   In this article I put a keyboard for activate and deactivate a alarms system with Arduino board and PIR sensor.

   My schematic is:

and sketch is alarm_system_2a.ino !

   My alarm work in next steps:

- after power on, alarm is OFF, blue led is on

- after you introduce the code (1234* or better #1234* because # clear buffer for old activity) system go to stand-by state, green led is blinking;

- after 20 seconds, system is in waitting (watching) mode, green led is permanent on;

- if PIR sensor detect movement, system begin to countdown, red led flash;

- if you indroduce code, system will be off (blue led in on)

- after 10 seconds (if you not enter the code) buzzer is on (led onboard is on), red led is permanet on

- after 10 seconds, system go to waitting mode, if is movement again, countdown and after buzzer is on, etc;

   You can see 2 movies with states of this alarm system:

- Arduino system alarm with delay (2)

- Arduino system alarm with delay (3)

Arduino alarm system with delay

original material

   At polish site named http://majsterkowo.pl/ I found an article about alarm system using a Arduino board and PIR sensor.
   Base schematic is 

and sketch for alarm is at page 3 in article.

   After I translate name of variables and study original sketch, I made some changes:

Note: I use internal led from Arduino board instead buzzer.
   
   My sketch is alarm_system_1a.ino and I have next states:
- switch is open, blue led is on, alarm is deactivate;

- switch is close (D2 at GND), green led is blinking, alarm is in stand-by

- after 20 seconds, green led in on, alarm is waitting
- if PIR sensor detect a movement, red led is blinking, alarm countdown 

- after 10 seconds, if switch is still close, red led is on, buzzer is active

- after 10 seconds, alarm return to waitting, if is movement, alarm countdown and repeat the cycle
- if switch is open, system in off.
   You can see a movie named Arduino system alarm with delay with all states: