nine years ago I build the first version of my wtf-counter - a huge emergency button connected to an arduino and a linux box that later got replaced with a raspberry pi. The button can be hit whenever a WTF! situation is happening in the office and the current count is displayed on a monitor. The installation is still in place and used quite a lot - but since I'm currently working at a customers site, I've build a second version. But since the toolstack I used for v1 is a bit dated by todays standards I decided to modernize it a bit.
The new version of the WTF-Counter uses a raspberry pi zero and the emergency button is directly connected to one of the gpio pins of the raspberry using only a resitor and a ts-jack. The pi writes an entry to a log file whenever the button is hit and uses a small monitor to display the current count using a small pygame programm. I didn't install an X-Server but draw the graphics directly on the framebuffer of my pi.
Reacting to a io-pin change is pretty easy - I registered a call back function that gets triggered whenever the pi recognizes a state change on the pin. The callback function then writes a line to a backup file with the current timestamp and increases the counter.
import RPi.GPIO as GPIO import time; import datetime; count = 0; def button_callback(channel): global count t = datetime.datetime.fromtimestamp(time.time()).strftime('%Y-%m-%d %H:%M:%S') f = open('wtf.txt', 'a+'); f.write("%s WTF!\n" %t); f.close(); print("WTF! %d" %count); count += 1 buttonPin = 10 GPIO.setmode(GPIO.BOARD) GPIO.setup(buttonPin, GPIO.IN, pull_up_down=GPIO.PUD_DOWN) GPIO.add_event_detect(buttonPin,GPIO.FALLING,callback=button_callback, bouncetime=200)
I also printed a small enclosure for my WTF-Counter on my 3D Printer and added a small text logo on the lid of the enclosing box by cutting out the letters from the lid and embossing them on a small plane so I could then glue them together.
The result looks way more polished than v1 and I'm quite pleased with the result.
grease pencil experiment 6 - grid
grease pencil experiment 4 - filled shapes
grease pencil experiment 4 - depth of field
grease pencil experiment 3 - animated circles