LAN-party in a box part 2

Part 2 - A new case

• Part 1

When thinking of a new case for the LAN box, I wanted to ensure it was easy to setup, and as portable as possible. As portable typically means 'small', it was necessary to consider the heat that would be generated by the computer when it was in use.

I purchased this ammo box from the local army surplus years ago, and it's only been used for storage, but it fits the bill nicely, it's fairly small in relation to the flight case I'd used before, has a handle for portability, and being metal should help dissipate the servers heat during use.

On top of all that, being an ammo tin, it fits the military/industrial aesthetic of Unreal well, but I wanted to do something to set it apart.

While I was planning this project, we were joking during our weekly games that we needed some kind of trophy that each weeks winner could keep on their desk, so I was looking at options for that, and I was toying with the idea of creating the iconic Unreal logo in brass, to create a shield-type trophy.

Then I figured we could combine the two ideas.


To start with I printed the logo to fit the 20x20cm brass that I ordered, and stuck the logo to the sheet to use as a template.

My original intent was to cut the brass on the bandsaw, but after a bit of testing, it was incredibly slow, and I found it easier to start by drilling around the logo, and then use a Dremel to cut out the shape by joining the holes together. From there it was just a case of grinding and filing down the edges.

The same process was used to cut a hole in the side of the ammo box for the window to be mounted, though as the metal was quite a bit thicker, I used an angle grinder for grinding down the edges.

The brass was glued and sandwiched between two sheets of clear acrylic, and mounted into the hole.

A post shared by Anthony (@darkmidnight_diy) on Jun 27, 2017 at 5:39am PDT

The original netbook that I used was too wide to fit the box, but I found another that just about fit - although I had to remove the screen, the battery, and pretty much anything else I could get away with ditching.

The next step was to add a band of WS2812 LEDs on the inside of the case, around the window, so that the logo could be backlit. To control them I used an Arduino Pro Micro, which I can in turn from the netbooks serial port. All the code will be covered in part 3.

A post shared by Anthony (@darkmidnight_diy) on Jul 24, 2017 at 7:55am PDT

Update: Part 3 available here

LAN-party in a box, part 1

Part 1 - The Story So Far
 
The title’s pretty much self-explanatory. My colleague, Ray, and I were talking about “The good old days” of online gaming – before Call of Duty, when the dominant games were Unreal Tournament, Quake 3, Counterstrike and the like.

We were toying with the idea of trying to run a LAN game over the work network, but figured the bureaucratic headache that would cause wasn’t worth it.

Then I got to thinking about how to cram everything we’d need for a LAN game into a single portable box, and could easily be set-up, used and torn down again within a lunch hour.

The great thing about returning to older games is that the system requirements, that once required hi-end PCs will now run on pretty much any old commodity hardware. What once meant lugging around heavy, bulky desktops, separate monitors and keyboards, could be replaced with a modern, lightweight laptop.

Ray was bringing in his laptop, and I setup an old laptop for me to use.

I installed Fedora 25 from a live CD (no particular reason for this distro, other than I had a live CD for it to hand – I’m sure others will work fine) Installed WINE, and the game.

We also wanted to use a dedicated server, so I dug through my stack of old hardware to find something to use - and I setup the server using an old netbook.

The networking was provided by an old home router of mine, which supplied DHCP configuration, making the network a straightforward plug and play.

This whole setup was stuffed into a metal flight-case for taking into work, and worked well for a spot of lunchtime multi-player, but there were a few downsides:

• Cabling – lots of mains plugs and network cables.
• Size - it's quite a substantial amount of gear to lug around - the flight case measures 33x46x15 cm and is packed pretty full.
• Although UT runs quite well in WINE, there is definitely some latency. The server seems fine, but graphically on the client machine, it's noticeable
  

The original setup - the netbook in the background is the current server.

Obviously something needs to be done to address the shortcomings, so this will form the basis of my next project - it should be a nice mix of DIY (for the case) and tech (hardware, software config, networking etc).

Update: Part 2 is now here

Remastering Tiny Core Linux

Tiny Core Linux is a lightweight Linux distribution designed for Live CD usage. Its low system requirements and small footprint also make it a good candidate for reviving older computers or as a base for building virtual machine appliances.

Unfortunately the remaster tool it includes, which is meant to allow for custom Live CDs to be created with chosen software pre-installed, seems to be buggy, and continually failed when I tried using it, so this is the alternative way I found to remaster TCL.

Step 1
Create a basic virtual machine and boot with the TCL Live CD. I used the CorePlus-current.iso, which has some extra software on there, but is still sub 100MB.






Once it's booted to the desktop select TC Install.

Select USB-HDD, whole disk and 'sda' options on the first screen.

Click through the next two screens (formatting options and boot options)

On the install type I checked the Installer Application option as I might need it in my intended application later, but it's optional.

Click through to the next screen where you're selected options will be repeated back to you, and select Proceed.

When it's done installing, shutdown the VM, remove the Live CD image and restart, so that it boots from the HD.

Step 2
Go to apps, and install the software that you require. In my case I installed Open JDK and Filezilla. (Filezilla also requires libiconv to be installed)

Reboot using the TC Exit options (from the menu go to Logout). The backup options there will essentially create a blank mydata.tgz file structure for you to use later.

Once rebooted, copy the /mnt/sda/tce1 folder off the VM to the host system/memory stick whatever (As I installed filezilla I FTP'd it to another server on my network.)

Step 3 (Optional)
On the host system, edit the mydata.tgz that you copied over, and add in any necessary files that you want on the Live CD. Thanks to the reboot that you did in step 2, mydata.tgz will have a basic file structure in place, that maps to the home and opt directories of the live CD. Also it puts in a couple of SH scripts, bootlocal.sh and shutdown.sh - these handle things that you want to execute on boot and shutdown respectively, edit those if you need to.

Step 4
Use an ISO editor (I used ISO Master).
Open the LiveCD, and navigate to it's 'cde' directory
Copy your mydata.tgz to the ISO, and replace its onboot.lst, and 'optional' directory with your own.

Navigate back to the ISOs /boot/isolinux directory and edit the isolinux.cfg file.
Find the line

TIMEOUT 600

This line causes it to sit on the bootloader screen for 60 seconds, unless the user selects and option.
I want my live CD to boot without user interaction, and that delay is redundant, so I edited it to

TIMEOUT 10

which allows a 1 second delay before continuing to boot the default option.


Save the edited ISO. To test, setup a blank VM like you did in step 1, and select the edited ISO as the boot medium. TCL should load, with your apps and files already there.

Dog-controlled treat dispenser part 2

This is the second part of my project to create a dog treat dispenser that my dog, Jack, can operate on his own. For the first part, click here.

Building an enclosure
I thought about 3d-printing an enclosure for the control box, but before I commit the time and effort to designing and printing one, I want to make sure that the project works - and that Jack actually uses it.
So for now, I've managed to fit the electronics into an old business card box, with basic cut outs for the buttons and wiring. It's not pretty, but it works.

The enclosure (the croc clips are for power - final version recycled a charger from a Playstation portable)

The floor switch is connected to the control box by a length of old VGA cable - it's nice and sturdy, and has more than enough wires for this project.

The components for the floor switch

In use
I finally managed to get a short video clip of Jack using it

Future improvements 

The floor switch is too light, as you can see in the video, when Jack uses it, he knocks it across the floor, so I've since mounted it to a bit of wood which helps hold it in place.

The small metal tin that I used to make the contact area larger & easier for Jack to use, ended up making the capacitive switch too sensitive - it basically became like a motion sensor - so I removed that, and used the original metal disc (about 15mm diameter) instead. Although the disc itself is smaller, it still manages to detect capacitance from contact anywhere on the switch, so it works just fine.

The floor switch - unfortunately the hot glue made a bit of a mess, but it's all contained on the underside of the switch, and actually helps diffuse the light a bit.

Source Code (Arduino cores for ATTiny2313

int latchPin = 8;
int clockPin = 12;
int dataPin = 11;
int capBtn = 7;

int plusBtn = 3;
int minBtn = 4;

int enabledLight = 5;

int motorPin = 6;

int treatCount = 0;
int valToDisplay = 0;
int timerBypassPin = 9;
long myTime;
boolean treatEnabled = false;

void setup() {
  //set pins to output so you can control the shift register
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  pinMode(capBtn, INPUT);
  pinMode(enabledLight, OUTPUT);
  pinMode(motorPin, OUTPUT);
  pinMode(plusBtn, INPUT);
  pinMode(minBtn, INPUT);
  pinMode(timerBypassPin, INPUT);
  digitalWrite(motorPin, LOW);
  digitalWrite(enabledLight, LOW);
  treatCount = 3;
}

void loop() {
  if (digitalRead(plusBtn) == HIGH) {
    treatCount++;
    if (treatCount > 8) { treatCount = 8; }
    delay(500);
  }
  
  if (digitalRead(minBtn) == HIGH) {
    treatCount--;
    if (treatCount < 0) { treatCount = 0; }
      delay(500);
  }
  
  if (digitalRead(timerBypassPin) == HIGH) {
    treatEnabled = true;
  }
  
  if (
      ((millis() - myTime) < 0) ||
      ((millis()-myTime) >= 3600000)
     ) {
    myTime = millis();
    treatEnabled = true;
  }
  digitalWrite(enabledLight, treatEnabled);

  if (digitalRead(capBtn) == HIGH) {
    if (treatEnabled) {
        digitalWrite(enabledLight, LOW);
        treatEnabled = false;
        treatCount--;
        digitalWrite(motorPin, HIGH);
        delay(3000);
        digitalWrite(motorPin, LOW);
    }
  }
  

  switch (treatCount) {
    case 0: valToDisplay = 0; break;
    case 1: valToDisplay = 1; break;
    case 2: valToDisplay = 3; break;
    case 3: valToDisplay = 7; break;
    case 4: valToDisplay = 15; break;
    case 5: valToDisplay = 31; break;
    case 6: valToDisplay = 63; break;
    case 7: valToDisplay = 127; break;
    case 8: valToDisplay = 255; break;
  }


  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, valToDisplay);
  digitalWrite(latchPin, HIGH);
  
}

Dog-controlled treat dispenser

I picked up one of these treat dispensers from Maplins on a whim - one of those "I'm-sure-I'll-find-a-use-for-this-someday" things. Subsequently I started wondering if I could train my dog, Jack, to use it (with some modifications, obviously)

An initial attempt involved simply wiring a switch to a footpedal for Jack to step on. That lasted all of 10 seconds as the plastic lid I'd repurposed as a pedal cracked under his weight.

One of the things that attracted me to the gadget in the first place was the capacitive button that it used. A quick test with my phone screen showed that dog's paws can operate capacitive switches.

Simply extending the leads alone wouldn't be enough. Although I want to give Jack the freedom to get his own treats, I still want to keep control over how many!

The touch sensors board has simple connections - just power, and leads out to the motor. I didn't really want to waste time modifying the board, as it's all small surface-mount components. Since I know the motor was only driven one direction by the board, I simply connected an optocoupler to the motor outputs. A couple of pull-up resistors later and the switch was done.

The finished capacitive button PCB with optocoupler

I connected a metal lid in place of the small capacitive disc to make it more dog-friendly.

Now onto the human's control system..

My original plan was to use something web connected such as an old android device, so that I could give Jack treats whilst out at work, but in practice, it was totally overkill, so I opted for a microcontroller based system instead.

The only controls I really need are to limit the number of available treats, set a time limit so he doesn't eat them all at once, and a way to see how many were available.

I found an old PCB with two buttons on it in my junk box. One button to add a treat, one to remove.

 

The salvaged button PCB (I believe it once belonged to a toaster...)

For a display I went with a 10-segment LED, controlled by a shift register. Due to the limitations of the shift register, the maximum treats available at any one time is 8 - which is more than enough anyway. The remaining 2 LEDs are left unused.

The 10 segment display (3 treats available) - the bottom 2 LEDs are not used.

The time limit I chose to fix at 1 hour in the microcontroller. As it's impossible to precisely measure the amount of treats that will be dispensed, the motor was set to a 3 second interval.

Finally I added a small LED module to the pedal, that lights when the timer ticks down and a treat is available, so that Jack could see when he can get a treat. According to the Pavlovian theory, he should soon learn that light=treat.

The LED module (it's just from one of those battery operated 'cupboard lights' you see in nearly every pound shop) - for this project I just connected a jumper over the button.

As with other projects I opted for using an Attiny (in this case the 2313) with the Attiny arduino cores, as they make it nice and easy to prototype with Arduino and switch to a regular AVR for the end product.

Stay tuned for part 2 - building an enclosure for it, some pictures of the completed project, source code, and hopefully some pictures/video of Jack using it.

UPDATE - Part 2 is now available here.