Category Archives: relaxing

Combining RRDtool with jpGraph for Heatmaps

Yes it works. Story below. Results:



How did he do it?

Simple. This is a combination of RRD Tool, jpGraph and PHP. RRD provides the database with measurements, jpGraph provides heat map graphs and PHP glues it all together. (colors are taken from exploded creepers from minecraft).

What am i seeing anyway?

It looks cool, but you’re looking at a heat map of the open/closed state of our hackerspace. For the last year, we’ve measured if the hackerspace was opened or closed. We measured about every five minutes.

The average of the past three months is displayed in a granularity of hours. This roughly means 2000 measures for a single graph. It renders nearly instant.

Step by step

Export measured values

rrdtool xport --start $e-$timespan --end $e --step 3600 --maxrows 4242 --enumds 


Spread the measured values by hours

foreach($measurements["data"]["row"] as $row) {
       switch ($row["t"] % 86400) {
           case 82800: $hourOpen[0] += $row["v0"]; break;
           case 0: $hourOpen[1] += $row["v0"]; break;


Shift is six hours, so primetime is clearly visible

       $element = array_shift($array);
       $array[] = $element;


Feed the data to jpgraph

$mp->SetSize(0.75, 0.7);


Other uses:

The same type of graph can also be used to visualize the temperature in a day. To see how the temperature rises over time. I don’t think there will be a rewrite though, definition of done.

Note: the graph is supposed to give an estimate if Hack42 is open or not.

See also

Eth0 Golden Ticket

In 2010, on 16/17 January, there will be the Eth0:2010 Winter edition. Eth0 is a socially oriented gathering of friendly geeks, girls and technology in the outer regions of the Netherlands. See link at the bottom for more info.

I just purchased a ticket. Due to some awesomeness in my head, i’ve got Eric Cartman screaming around with the text “i’ve got a golden ticket, i’ve got a golden ticket”. So I decided to pimp up the ticket; with a subtle gold touch. In the end everything was gold-plated to give it that extra feel. Shoop da woop.





Unfortunately the qcode doesn’t work anymore.

See also

Spel zonder regels

De volgende blogpost is geschreven volgens de hyper-japanse-chaos-stijl, letterlijk vertaald naar het engels. Sterkte, het is de moeite waard. (comments disabled… due to spam)

Presenting to you! All new ACTION GAME!


Contains 4 AMAZING level star you: WHITE SPRITE CAT (red: affiliate of CAT GOD) will have to cross and face. No better game has ever made, you will be challange! No rules, only game. Game you will be ever happy with. Watch SCREEN SHOTS, WALLPAPER, YOUTUBE and PLAY GAME NOW!

Find resources:

Promotion wallpapers! DOWNLOAD! Syobon action wallpaper & Syobon action wallpaper soft

See for IN-GAME HIGH resoultion screenshots action!!


MUSHROOM: mushroom makes you heavy!

WARP ZONE: warpu zpne!

POWER BLOCK: powerup will make you fail!

LIVE: minus lives!

See level 1! Makes you win! Makes YOU feel STRONG!

Fast DOWNLOAD GAME! FREE No Spyspyware! No lookylookyware! FREE GAME!

No resembaling to mario! ORIGINAL GAME! play now!

De pinautomaat

Datum: 27 September 2003

Locatie: Venlo

Hamvraag: Kan ik een filmpje maken met 27 foto’s?


Met dank aan: MrGr33n & Mol (zie high-res film voor de 1 frame credits). Gemaakt met iMovie, een digitale camera en amadeus II (iets wat lijkt op cooledit).

Download de high-res quicktime (m4v) versie van 14 meg.