After putting together the rotary phone beaglebone machine, I decided that I still needed to do something with the extra pinouts on the beaglebone. Since I had recently started using MyTinyTodo to keep track of my todo list, I thought it would be nice to have a quick visual display of how many things are still on my todo list.

To Accomplish this my goal, I would need to add some LEDs to the beagle bone and then hack some code to do what needs doing. First thing first: add the idea to the todo list.

Gather Some Components

In order to get this project going, a trip to the nearby electronics store was in order. After returning home with 10 green LEDs ( the plan was to use 6, but I figured buying extra would let me fry a few), I realized that there was a lack of 100 Ohm resistors in my home.

Fortunately, I had some 50 Ohms that I soldered in series to handle the job.

This is a very boring pictures; don't look at it.

Solder 6 of These

This is the basic circuit that get's wired to the BeagleBone. The extra length of wire will get cut off and the entire thing will be wrapped in a bit of electrical tape.

While I was at the electronics store, I bought some fans to replace the fans in the clock server because I think it runs too hot.

The Finished Circuit

Well looky looky! The circuit is finished. Six LEDs with a common ground, with a 100 Ohms of resistance for each LED.

Time to wrap these babies up with electrical tape and hot glue them into the BeagleBone's case.

Glued in Place

On the third attempt, I managed to almost get the LEDs glued into place where I wanted them. Yea, it took me a few time of gluing, and then prying the LEDs from the case a regluing before things were working properly.

As it is, one of the LEDs still doesn't let the box close very easily. Terrible terrible design. That's it! I'm firing myself.

Oh hey! This is probably the best picture that shows off the flowers etched in the glass.

7 Things On The ToDo List

At the time this picture was taken, there were 7 things on my todo list. But there are only 3 LEDs lit up. That's right, the LEDs need to be counted in binary from left to right.

With this setup, using 6 LEDs, the ToDo List will max out at 63 items; and I if I have that many things to do, something is very wrong.

Every 5 minutes, the LEDs run a simple animation sequence, parse the ToDo List RSS feed and then turn on or turn off LEDs as necessary.

Since there is still plenty of room in the box, I'm thinking of adding another something-or-other that is controlled by the BeagleBone pins. I'm not sure what it will be, but I can guarantee I'll have fun making it.

Hack on!

PS. I really want to have 15 things on my ToDo list, just so I can say "THERE...ARE...FOUR...LIGHTS" Ha hahahaha, I crack me up.

Rocking the Rambler

Remember the dash of my buddy's 1966 Rambler from http://www.jezra.net/blog/The_Wrench? Well, that dash has a stock AM radio that looks really nice. Unfortunately, there aren't very many AM radio stations in the area that play music worthy of listening to in a 1966 Rambler. So, for my buddy's birthday, I decided to make an AM transmitter that would deliver music of his choosing to his radio in sweet sweet monophonic sound.

Schematic

A quick internet search for "simple AM transmitter" let me to http://justtechnika.com/articles/circuit-diagram-simple-digital-am-transmitter/, which seemed to be exactly what I needed. About $5 later, the components needed to make three of these things were on their way to my home from digikey

After a few minutes of figuring out where things needed to go, I had a working prototype on a development board. I accidentally left out the 1000 micro farad / 25 volt capacitor. Oh well, it still works.

Test the prototype

The first test of the prototype took place with my alarm clock AM radio and I really needed to test this on the real thing.

Hey Buddy, bring your car over here!

The transmitter worked like a charm as long as the transmitter antenna was touching the radio antenna. (this is a good thing)

The real deal

A month or so after I started this project, I had a finished circuit ready to deliver to my buddy and a small burn on my finger. Damn soldering iron. The finished product is about 5x3 centimeters in size and a power switch has been added.

Hopefully the circuit doesn't sit around his apartment gathering dust.
hint hint

Hey Buddy! We should hella install that transmitter this weekend

A bit of Computer Repair

My good buddy Constance has a rather old computer. Actually, it is an original ibook with a speedy 300Mhz processor and a whopping 192M of RAM.

OK, the RAM has obviously been updated, but other than that, the computer is still original.

One day, Constance told me a tale of tripping over her computer cord and then the adapter started sparking. Crap! The machine may be crap, but it is all she has and it has all of her writings on it.

Ah, the slow as dirt machine. See that "yo-yo" power adapter? Aside from always burning out, those things are $80 from Apple. I'll be damned if I let Apple get any of my poor writer friend's money. Let's fix that shit!

First thing first: find out where the cord is fried. Well, I'll be damned, it just happens to be fried where every other "yo-yo" adapter gets fried.
(That's me being sarcastic)

It went like this:
1. cut off part of the plastic housing
2. cut and strip wires
3. determine that the amount of exposed wire is to too short for my pathetic soldering skills
4. cut off all of the plastic housing
5. discard the metal housing under the plastic housing

Hit it with some magic!

After soldering the wires, I used hot glue to re-attach part of the plastic housing and then I wrapped the wires with electrical tape. Just to be save, I slather on a crapload of hot glue to keep everything together.

Solder, electrical tape, and hot glue. Shazaam! That's three adhesives in one project!

When the repair was completed, I put the machine in bag and pedaled over to Constance's house, where I was greeted ecstatically. It should be noted however, that there was a serious lack of cookies/coffee/beer/scotch waiting for me when I got there. cough cough, cough cough cough, hint hint.

Now quit reading, and go repair a crappy 11 year old laptop.

P.S. If anyone has an old laptop gathering dust, and the laptop isn't as crappy as Constance's current piece of shit, let me know. (Constance really needs an upgrade)

The tag on the phone said:
phone
as-is
$8.50

Perfect.
In various states of functionality, there are about 15 rotary phones in my home, this particular phone however, is destined for a different sort of communication.
Based upon the schematic that was used for the serial switch project I really wanted to make a multi-switch input device. It would be easy to simply solder on two more switches to the existing project and then run various commands when each switch is pressed, but that wouldn't be much fun. Fortunately, I know that a rotary phone has three switches inside. Let the fun begin.

The phone was light, too light. From experience, I had guessed that the ringer was gutted from this phone. Not only was the ringer gutted, but most of the internals where also removed. Oh well, it makes things easier for me. Here you can see the body, the internal cradle switch mechanism, and the back of the dialer.

Perhaps I should do this with every phone I have with a missing or broken ringer.

Step 1. Determine which of the wires coming from cradle switch from a closed circuit when the headset is placed on the cradle. There can't be more than 8 wires so it should be fairly easy to do.

Whoops. Wow, those things fall apart fairly easily and I was left with a pile of wires, switch contact points, spacers, and a sense of determination.

This is about 75% of the wires.

Hey, that wasn't too hard to put back together. Much like the toys I insisted on taking apart as a child, this switch was put back together with a few parts missing.

Actually, I only needed two contact point to make the switch work the way I want it to. The extra contact points were added to give pull on the slotted bar connected to the spring lever.

This is a close of up the back of the rotary. There are two switches here that I will refer to as the rotator and the dialer. If the rotary is moving then the rotator switch is making a closed circuit. The dialier on the other hand is normally closed, but when the rotary is swinging back to its default stationary position after a user has dialed a number, the dialer switch will break the circuit a number of times equal to the number that was selected. After the rotary has finally parked in the stationary position, the rotator switch opens and breaks the circuit.

Three switches means 6 connections: 3 grounds and 3 leads. Since the three grounds will be soldered to the same pin on the serial port, I only need a 4 wire cable. Fortunately I had a spare black USB cable( and USB cables only have four wires).

All soldered up and ready for electrical tape. OK, I used duct-tape.

All done with the hardware, now it is coding time!
Fast forward an hour
The code is done and everthing is working as expected. So how does it work?
1. pick headset off of cradle
2. dial a number that corresponds with a command in the configuration file
3. hang up the phone
4. the command is run on the computer

• dialing "1" will run the command "firefox http://www.linuxoutlaws.com " which will open the Linux Outlaws website in Firefox.
• dialing "2" will play the latest episode of my favorite audcast; It is time to remove the pod and put in some aud-io.
• dialing "22" will play the Conan Soundtrack
• dialing "23" will play compositions by Basil Poledouris (randomly)
• "3" will quit all audio players
• "01189998819991197253" will run "firefox http://www.youtube.com/watch?v=RK4Xye7AErE "

#!/usr/bin/env python
import serial
import gobject
import os
import sys
import subprocess

class serial_checker (gobject.GObject):
    def __init__(self):
        self.config = {"port":0,"carrier_detect_pressed":"echo carrier\ detect\ pressed\n"}
        #read the config file
        cfile = os.path.expanduser("~/.serial_switch" )
        file_lines = open(cfile)
        for line in file_lines:
            #trim the white spaces
            line = line.strip()
            #if the line has length and the first char isn't a hash
            if len(line) and line[0]!="#":
                #this is a parsible line
                (key,value) = line.split(":",1)
                self.config[key.strip()] = value.strip()
                
        self.cd_switch_down = False
        self.cd_switch_action_running = False
        gobject.GObject.__init__(self)
        self.switch_count = 0
        #define our serial
        self.ser = serial.Serial(self.config["port"])
        self.mainloop = gobject.MainLoop()
        gobject.timeout_add(150, self.check_switches )
    
    def cd_switch_action(self):
        #what is the user requested command?
        command = self.config["carrier_detect_pressed"]
        #print command
        #run the command, this should be in a thread or asynchronous
        subprocess.Popen(command,shell=True)
        
    def run(self):
        #run the main loop
            self.mainloop.run()
    
    #check the switches
    def check_switches(self):
        cdval = self.ser.getCD()
        if (cdval):
            if(self.cd_switch_down==False):
                self.cd_switch_down = True
                #try to run the cd switch action
                self.cd_switch_action()
        else:
            self.cd_switch_down = False

        return True
    
    #when the class is closed, clean up
    def __del__(self):
        self.ser.close()
        self.mainloop.quit()
        

if (__name__=="__main__"):
    ser_check = serial_checker()
    ser_check.run()

# this is a config file for serial_switch
# all configurations will be in key:value format

# serial port (default /dev/ttyS0 )
#port:/dev/ttyS0

#what happens when the carrier_detect switch is pressed
carrier_detect_pressed: gmrun