I'm building a thermostat system for our turtle's breeding terrarium.
Basicaly, it'll control the temperatures in two zones of the terrarium, giving me the ability to set up the temperature I want for each zone per time period (e.g. 26°c from 10:00 to 18:30 and at least 20°c the rest of the time in Zone1 and 31°c from 11:00 to 17h30 and at least 21°c the rest of the time in Zone2)

I'm using an atmega168 (not an atmega8 like the schematics says, but it's pin compatible), a 32.768khz xtal for the time, two 5v relays, and two p-channel mosfets to drive those relays, and an 2×16 LCD.

Here's what i think the board will look like (design not tested yet)

the code is still work in progress, but i'll post it later

Edit: February 18th 2010
Still no update on the code, but here are some pics of the actual board :


yeah, the DIP IC socket should be reversed, I saw that too late, but no big deal, cause i know that ;)

Ladies and gentlemen, let me introduce you the DIY servo tester I made:

So first of all how do servos work? it's simple, really, most of them have 3 pins: VCC, GND, and PWM Hook the VCC pin to 5v, the GND one to 0v, and the PWM pin to a device that generates a 50hz pwm signal (a square signal with a variable duty cycle) with the smallest duty cycle handled by the servo the angular position is at its maximum position clockwise, and with the highest duty cycle handled by the servo the angular position is at its maximum counterclockwise.

My problem was to find those values!

As you can see on the picture the length of the pulse was 1.82ms which is 9.13% (duty cycle) of a 50 Hz period (20ms). Since I use the built-in pwm function provided by the atmega168 (the microcontroller I use) the OCR1A value and the top value associated (ICR1) I can generate an accurate square signal. Some internal counter starts at 0 with the output at 5v, when it reaches ORC1A the output goes to 0v, and when it reaches ICR1, the counter resets, and the output goes to 5v again and so on…

Anyway, there are to buttons, one to make it go CW, decreasing the OCR1A value, one to make it go CCW, increasing the OCR1A values… now all I have to do is read the values when it won't go any further in both directions…

I'm going to post the source code and the schematics as soon as possible !

Since a picture is worth a thousand words, lets start with them:

What I think is pretty simple (maybe too simple): the distance between the y axis and the edge of the object where the laser is beaming on, can be calculated using the delta value and some sines and cosines!

I'm not much of a math guy, but this sounds really easy!

x=delta/sin 60

Waaaaait… this may actually work!!!!

Oh and i've made some huge progress with my realtime webcam tracking program!

here's an example tracking my external harddrive blue led:

click to view the whole layout

Since I can't etch something >300mm, I have to split each board in two parts.

So we have the logic boards (74×4094, and uln2803) on the top, and the "matrices" boards (with the led matrices) on the bottom.

The power board (with the mosfets), and the controller board (with the µC) are still in dev.

Once again i've been very busy lately…

Here's a preview of my new project… meet the 640-led-display(-to-be)!

Ok for now only 2 matrices (=128 leds), but there are way to much wire on that breadboard… even with only two of them!



Project Pictures




Project parts (estimated):

Todo list:

The hardware/software may not be very optimised, but the clock is quite accurate! :p

1. The timer

How does it work?

the timer is increased by one every P clock ticks (P is the prescaler, its value can be 1,8,64,256,1024), and it generate an interrupt each time it overflows (255 to 0)
Now we have timer_interrupt_frequency = F_CPU/(P*256)
thus with a 11,0592Mhz crystal, and P=64, the timer interrupt frequency is: 11059200/(64*256) = 675Hz (yeah exactly 675, not 675,00000000001 nor 674.9999999999999999999999, … 675!)

That means that 1 second = 675 interrupts
we just need to increase the seconds every 675 interrupts, the minutes every 60 seconds, the hours every 60 minutes, …

2. the 7 segment displays

how to drive 7*4= 28 leds ?
remember, we do not have 28 i/o pins! the solution? Charlieplexing!
the 4 cathods (one per display) of each segments are linked together to 7i/o pins and the 4 common anodes are linked to 4 i/o pins
and we make the whole thing go so fast that human eye sees the four displays on at the same time(remember pov "article")

3. the electronical part
schematic

4. the source code

Download this code: avrclock.c

5. the final result

both of them use an atmega8 avr microcontroller (which is very easy, cheap, and a lot better than mid-range pic)

Since i'm new to avrs my first project will be something easy :p

He's using a Parallax HomeWork Board (I don't know the price but i think it's quite expensive) thus I've decided to do the same thing with low cost equipement (16F84)

1) the electronical part

why do I use a 16F84:

The board:

as you can see, you do not need to have a lot of stuff on the board

The pin diagram

The schematic diagram

R=120 ohm
C=15pF
X=4Mhz

2) The assembly code part

Download this code: pov.asm

because i'm very lazy, i do not have typed all that byte sequence myself…
i wrote a tiny perl script who analyses a small picture (8px * 60px) and generate the byte sequence for me

picture:

source code:

[The requested file http://dev.pulsed.net/wp/code/pov%20bsg.pl could not be found]

3)And now the result:
Poor quality (extracted from a video i took with my cellphone…) [i do not have a digital camera]

this one is flipped (nice frame at return)

1337 ^^

the whole 1337 thing is just a joke

1) smokewhat?

Smokeping(link) is a nice latency measurement tool, unfortunately it WAS only available for linux/unix…but after the jump, you'll find how to make it work under Microsoft Windows!

SmokePing is a deluxe latency measurement tool. It can measure, store and display latency, latency distribution and packet loss. SmokePing uses RRDtool to maintain a longterm data-store and to draw pretty graphs, giving up to the minute information on the state of each network connection.

2) What you need

- Perl (choose Perl 5.8.xxx MSI package for Windows)
Yeah Perl is cool and you can have a lot of fun using it

- RRDs module for Perl
This version works for sure, but feel free to download the latest

- fping for windows (thanks to Michael Parson)

- Smokeping
This version works for sure, but feel free to download the latest

- a text editor
There's a lot of text editors out there… personally, I like pspad

- a web server
Feel free to download, install, configure apache with cgi yourself, or use WAMP (the one I use), or whatever bundled apache/cgi/php/mysql version you want

3) What you do not need

- Money
all listed softwares are (at least) freeware

- A (linux/unix)-running computer
yeah dude, windows rulez da w0rld

4) "Installation"

- Install Activestate Perl
- Install RRDtool for windows (unzip, and launch install.cmd)
- Unzip smokeping to C:\smokeping-2.0.8
- Unzip fping for windows (make sure cygwin1.dll is in the same folder) to C:\smokeping-2.0.8\fping
- Install WAMP to C:\wamp

5) Modifications

a) rename
- C:\smokeping-2.0.8\bin\smokeping.dist into smokeping.pl
- C:\smokeping-2.0.8\bin\tSmoke.dist into tSmoke.pl

b) edit
- C:\smokeping- 2.0.8\bin\smokeping.pl
add (after line 5): use lib qw(C:\smokeping-2.0.8\lib);
change (line 9): Smokeping::main("etc/config.dist"); into Smokeping::main("C:/smokeping-2.0.8/etc/config.dist");

- C:\smokeping-2.0.8\bin\tSmoke.pl
change (line 63): my $cfgfile = "etc/config.dist"; into my $cfgfile = "C:\smokeping-2.0.8\etc\config.dist";

- C:\smokeping- 2.0.8\lib\Smokeping.pm
change (line 14): use Sys::Syslog qw(:DEFAULT setlogsock); into #use Sys::Syslog qw(:DEFAULT setlogsock);
change (line 21): $ENV{LC_NUMERIC}='C'; into #$ENV{LC_NUMERIC}='C';
change (line 22): POSIX::setlocale(&POSIX::LC_NUMERIC,""); into #POSIX::setlocale(&POSIX::LC_NUMERIC,"");
change (line 2984): daemonize_me $cfg->{General}{piddir}."/smokeping.pid"; into #daemonize_me $cfg->{General}{piddir}."/smokeping.pid";

- C:\wamp\Apache2\conf\httpd.conf
change (line 515): ScriptAlias /cgi-bin/ "C:/wamp/Apache2/cgi-bin/" into ScriptAlias /cgi-bin/ "c:/wamp/cgi/"
change (line 521): <Directory "C:/wamp/Apache2/cgi-bin/"> into <Directory "c:/wamp/cgi">

c) move and rename
- Create folder c:\wamp\cgi
- C:\smokeping-2.0.8\htdocs\smokeping.cgi.dist to c:\wamp\cgi\smokeping.pl

d) edit
- c:\wamp\cgi\smokeping.pl
change (line 1): #!/usr/sepp/bin/speedy -w into #!C:/Perl/bin/perl.exe -w
change (line 5): use lib qw(/home/oetiker/data/projects/AADJ-smokeping/dist/lib); into use lib qw(C:\smokeping-2.0.8\lib);
change (line 10): Smokeping::cgi("/home/oetiker/data/projects/AADJ-smokeping/dist/etc/config"); into Smokeping::cgi("C:/smokeping-2.0.8/etc/config.dist");

6) Configuration

- Create folders:
C:\wamp\www\simg
C:\smokeping- 2.0.8\var

- edit configuration file ( C:\smokeping- 2.0.8\etc\config.dist ) no line number here use search function instead :p

owner =
contact =
mailhost =
#sendmail = /usr/lib/sendmail < == Comment this line
imgcache = C:/wamp/www/simg
imgurl = ../simg
datadir = \smokeping-2.0.8/var # designate implicitly c:\smokeping-2.0.8\var
piddir = C:/smokeping-2.0.8/var
cgiurl = http://127.0.0.1/cgi-bin/smokeping.pl
smokemail = C:/smokeping-2.0.8/etc/smokemail.dist
tmail = C:/smokeping-2.0.8/etc/tmail.dist

# syslogfacility = local0 < = Comment this line!!!!

*** Alerts ***
to =
from =

template = C:/smokeping-2.0.8/etc/basepage.html.dist

+ FPing
binary = C:/smokeping-2.0.8/fping/fping.exe

title =
remark =

# google is for demonstrational purpose only; please refer to smokeping help to set your own targets

+ Google

menu = Google
title =Google Connectivity
alerts = bigloss,someloss,startloss
host = google.fr

7) Test it!

- open a cmd.exe window, and type C:\smokeping-2.0.8\bin\smokeping.pl

Ok, no weird error messages (if not, please check 5-a, 5-b and 6 again)

- let it run for 10-15 min and try to open http://127.0.0.1/cgi-bin/smokeping.pl

Ok, no error messages again (if not: for cgi error check 5-b, 5-c, 5-d and 6 again and 5-d and 6 for RRD errors)
(note the 2 buggy images bottom left, we will fix this later)

Now close the cmd.exe windows (a little bit rebel)

8) Autostart under NT AUTHORITY\SYSTEM

- open Control Panel > Scheduled tasks and then click add scheduled task
since I'm french, my Windows version is french too

add scheduled task

Next

C:\smokeping-2.0.8\bin\smokeping.pl

When my computer starts

system

After that, click "Open advanced properties for this task when i click finish"

Check that "run as" is "NT AUTHORITY\SYSTEM"

Uncheck everything in parameters, and click OK

right click on the task, and Start, check if it doesn't stop immediatly.

9) The two buggy png pics

Download them, and overwrite those in C:\wamp\www\simg

10) And you're done

I'm not a native English speaker, so if you find some orthographical or grammatical mistakes, please report it!