17 January, 2016

Casualty Simulator Android App

A friend was discussing with me various prop idea which we could make with Arduino in particular, but there are "virtual props" that you can build in software. Virtual props are particularly well suited to logic driven props which are hard to build in the physical world.

As an example I built this Casualty Simulator for Android DEMO. This is a demo intended only as a proof of concept. It is not intended for use as is, although it should be usable with limitations.

It should run on fairly old Android devices, but may struggle if they are really underpowered.

Basically it is an Android app which is designed to be running on an Android device placed on a casualty which will be carried on a stretcher. The app detects if the casualty is pitched about dangerously and every time that happens, the app cries out in pain and the casualty loses health.

When the casualties health reaches zero the casualty is dead. The players can "Give Treatment" to the casualty a maximum of three times, which will add 20 health points back. This is to simulate bandaging, transfusion or adrenaline treatments.

Note that the players cannot give treatment to a dead casualty, nor can they heal a healthy casualty above 100 health.

There is an audio heartbeat monitor which slows down as the casualty gets closer to death. This gives the players some approximate feedback on the casualties status. To get an accurate status the players can click the "Check Health" button as often as they like.

If the casualty dies there is an audio feedback of a heartbeat monitor flat-lining, and on screen text to alert the players.

To prevent cheating the app displays a simple log of the starting and stopping of the app along with some other useful info.

To reuse again, simply quit and restart the app. Start/Stop acts like a play and pause function, not a restart.

Please note you need to long press the Start/Stop button to minimise accidental Start Stops.

Finally, this is a concept demo, if anybody wants me to develop it further, please contact me through the contact page. I guess if anybody wants to use it, they will want to be able to edit all the parameters, such as health, sensitivity, treatments.

Installation Instructions

Before you can click on the download link you must enable the ability to install software from "Unknown Sources" and you must manually un-install any earlier copies of the software.

"Android protects users from inadvertent download and install of apps from locations other than Google Play (which is trusted). It blocks such installs until the user opts-in Unknown sources in Settings > Security, where you will see an option similar to the option shown below. To allow the installation of applications from other sources, users need to enable the Unknown sources setting on their devices, and they need to make this configuration change before they download your application to their devices." 

The text may also say "Allow installation of apps from sources other than the Play Store."
Note: You would be wise to disable this option after you have successfully installed the software.

From your android device you can now access the download link and the software will be installed on your device. The download link is available after you accept the Warning and Liability Notice below.


Software downloaded from the CrapWorks web site or from other sources is provided 'as is' without warranty of any kind, either express or implied, including, but not limited to, the implied warranties of fitness for a purpose, or the warranty of non-infringement. Without limiting the foregoing, the CrapWorks makes no warranty that:

  • the software will meet your requirements
  • the software will be uninterrupted, timely, secure or error-free
  • the results that may be obtained from the use of the software will be effective, accurate or reliable
  • the quality of the software will meet your expectations
  • any errors in the software obtained from the CrapWorks web site will be corrected.
  • the software is complete and free of defects

Software and its documentation made available on the CrapWorks web site:

  • could include technical or other mistakes, inaccuracies or typographical errors. The CrapWorks may make changes to the software or documentation made available on its web site.
  • may be out of date, and the CrapWorks makes no commitment to update such materials.

The CrapWorks assumes no responsibility for errors or ommissions in the software or documentation available from its web site.

In no event shall the CrapWorks be liable to you or any third parties for any special, punitive, incidental, indirect or consequential damages of any kind, or any damages whatsoever, including, without limitation, those resulting from loss of use, data or profits, whether or not the CrapWorks has been advised of the possibility of such damages, and on any theory of liability, arising out of or in connection with the use of this software.

The use of the software downloaded through the CrapWorks site or other sources is done at your own discretion and risk and with agreement that you will be solely responsible for any damage to your computer system or loss of data that results from such activities. No advice or information, whether oral or written, obtained by you from the CrapWorks or from the CrapWorks web site shall create any warranty for the software.


07 April, 2015

M1911A1 Real Wood Grips Part 1

Over the Easter Holiday I decided to make a set of real wood grips for my M1911A1 to replace the nasty dark brown plastic grips which were on the pistol.

The M1911A1 is part of my Namsofting Loadout. Brown plastic grips are actually historically accurate on 1911s from WW2 onwards, but I like to imagine my 1911 was in fact an upgraded personal item rather than standard issue.

I could have bought some mass produced wooden grips cheaper, but the wood on those things is usually some nasty crap which was never on a real piece. I selected American Black Walnut, which is authentic for the M1911 and a premium quality woodworking timber.

This post is part one of a two part post. In this post I will cover how I made the grips and in the next post I will cover checkering. Checkering is the gunsmithing term for the diamond grip pattern. I think the smooth grips are very nice as they show the wood grain pattern to full effect due to their smoothness and uniformity. Much of the grain effect will be lost with the checkering.

As usual for my posts, here is a picture of the finished grips fitted to the M1911A1...

The CO2 mag is not exactly authentic! :-/
I started by finding somebody elses DXF files from a forum. I imported them into Solid Edge ST7, but ended up doing so much revision to them that I might as well have just drafted my own from scratch.

Revised DXF in Solid Edge ST7
I imported the revised DXF into CamBam and generated the toolpaths...

The most awesome CamBam
From there I generated G code which I fed into my CNC Router to cut the grips.,.

A clean workshop is a safe workshop! *cough*
This is how the grips come off the CNC Router...

As you can see there is still a lot of work to do on these grips to get them to a finished state. I finished cutting the grips out with a fret-saw and made this little jig to enable me to sand them on my belt sander without sanding my fingertips off (again!!!).

This little jig was made with 2 dowels and a board with similarly spaced holes. It enabled me to sand the grips while only sanding one knuckle bloody. Progress!!!

The sanding with a 400 grit belt really brings out the woodgrain.

I repeated the sanding on the other grip and test fit the grips to the pistol. They needed quite a bit of hand carving on the back face to make them fit the pistol correctly.

Two coats of Danish Oil really makes the wood-grain pop...

Before and After Danish Oil
The lustre turns much more matt and natural as the Danish Oil soaks into the wood.

Here are the wood grips side by side with the old plastic ones...

You can see that the lustre has gone.

Finally, here is another picture with the grips fitted to the pistol..

I am very happy with the finished result, so much that I am really reluctant to checker them now. I think I will make a second set and keep whichever ones I like best.

Thanks for reading and lookout for part two, coming as soon as my checkering tools arrive. :)

Update: The checkering tools have still not arrived so I made these grips from a very nice piece of Burr Elm.

Scottish Burr Elm Grips

The figuring on this wood is very nice

These were also popular.

06 April, 2015

Plywood Monitor Project aka Upcycling an old laptop display to a new monitor

It is surprisingly easy to build your own monitor for a desktop computer by recycling the flat panel display from an old laptop.

I had an obsolete HP laptop with a nice 17-inch display which was about four years old. It had long since been replaced by something a lot more capable.

From that old laptop I built this monitor..

The monitor I built is on the left, my existing monitor is on the right.
This blog post is how I got from old laptop to new monitor. It was not terribly challenging and I figure most people have an old laptop somewhere and could tackle this kind of project in some shape or form with a minimal set of tools and electronics experience. I do not want to mislead any reader into thinking that I came up with this method for recycling old laptop displays. I know for a fact that I did not, and there are many tutorials on YouTube, Instructables, etc, which I urge anybody thinking of following in my footsteps to view. This is just a record of my attempt at this kind of project.

The first step was to power on the old laptop, and actually check that the display functions and was not faulty. In particular I was looking for those annoying dead or stuck pixels...

image source: http://electronicrepairing.blogspot.co.uk/
I personally can't live with those and I would not put the effort into this project if the donor laptops display had any of these faults.

The next task was to carefully take apart the laptop. There was no point in using brute force here as flat panel displays are quite fragile and very easily damaged, so carefully with screwdrivers I unscrewed anything I thought may be holding the display in position. I carefully set the screws aside in the order in which they were removed in case I wanted to put the laptop back together again or in case I wanted to reuse the display casing for the new monitor as well as the flat panel display itself.

Taking apart the old laptop and display
After taking apart the old laptop and gently disconnecting everything connected to the flat panel display, I had to find out the exact model and who made the display. This step is essential to purchasing the correct electronics I needed to convert the display from a laptop display to a monitor.
The make and model is usually displayed on the back of the panel on a sticker...

Red arrows point to the make and model
It might surprise readers that even though this was an old HP (Hewlett Packard) laptop, the display was in fact made by LG. Just because a laptop is sold by a particular manufacturer you cannot assume that the display was also made by that same manufacturer.

Armed with the make and model I searched Google for lp171wp4 tl n2 controller...

Which returned a load of results. I bought my controller electronics from eBay seller njytouch for US$37.49 including delivery from China. The electronics arrived as promised a couple of weeks later.

The electronics are quite simple to assemble. The connectors only plug in one way, and as long as you do not force anything, it is very difficult to screw that up.

image source: njytouch. Left to right. Lamp board, Main board, Control panel
These new electronics replaced all the electronics from the old laptop. It is simply a case of swapping out the laptops electronics for these electronics. No tools required! The main board supplied by njytouch has a number of options for connecting to your desktop computer.VGA, DVI-I and HDMI. Of these three options the lesser is VGA which is an old school analogue signal. DVI-I is a better quality pure digital video signal and HDMI is digital video and sound combined. I opted to use the HDMI connector.

The black cable with the golden connector you can see attached to the main board plugs into the back of the flat panel display. The only other connection to be made is the tiny 'lamp' cable coming from the back of the flat panel which plugs into that orange/peach coloured connector on the lamp board. Two connections are all that are required to complete the electronics part of this project. It was now a question of connecting my desktop computer to the mainboard with a HDMI cable and powering the new monitor with a DC power adaptor and I had a working if not very pretty monitor.

Njytouch recommends powering the controller with a 12 volt, 4 amp DC adapter, and sells an adaptor to do this from his eBay page. I actually had a 12 volt 1 amp adapter in my spares box from an old Netgear router. Although this adaptor could supply less current than recommended, it worked and saved me having to buy another adaptor.

Now that I had a working and functional monitor, I had to decide what I was going to house the electronics in. 

My choices were:
  1. Do nothing and leave it all hanging out.
  2. Reassemble the display half of the laptop and cut a few holes for wires, etc,.
  3. Build a simple and functional case from plywood.
  4. Go all out and hand carve a case from hardwood.
As there was no need to make a rush decision, I actually opted for choice #1 for two weeks. As this would be a second display on my gaming battlestation, this enabled me to position the new monitor in various locations and orientations. For a week or so I had the new monitor in the "portrait" orientation instead of the traditional "landscape" orientation. This was not as useful as I hoped with software applications optimised for viewing in landscape. Those two weeks were useful in determining that the best location was at the same height as my existing display and the best orientation was landscape. 

After toying with the idea of building an elaborate and beautiful hand carved case, I decided to build one from some nice Baltic Birch furniture plywood I had in my workshop. Before I get into that the simplest choice would have been choice #2, to re-assemble the display half of the laptop, and this is in fact what most people who do not have access to a woodworking workshop actually do. This is illustrated quite well in this lifehacker post, where the original display case has been reused and augmented with a Mecanno stand. I have also seen Lego used like this to build a stand.

image source: lifehacker / gawker. Reusing the laptop display casing.
I decided to build a case with the 18mm thick plywood with very simple and clean lines. the look I was going for was "if Ikea built monitors". The main tool I used was my home built CNC Router Robot which I have described in an earlier post. I could have made this just as well on my bandsaw and router table.

After making detailed measurements of the parts, I designed the casing in Siemens Solid Edge ST7 and imported the DXF drawings into CamBam...

Display Surround, Back Panel and Control Panel

Tilt adjustable legs

Base plate

From there I exported the toolpaths to G-code and cut them on my CNC Router...

Cutting...dust everywhere!

Finished Cutting
I cut all the parts like this then finished them by hand with a Japanese pull saw, then 80, 180 and 400 grit sandpapers. All that was left to do was assemble the parts with wood glue, let that dry and then give the entire assembly a rub down with Danish Oil.

Starting the assembly of the plywood case
The base and case assembled, and clamped while the glue dries
The tilting mechanism is some washers, 6mm threaded wash and some nylon lock nuts
The electronics were stuck to the back of the monitor with double sides foam tape then screwed to the back panel for extra robustness.

The completed monitor in-situ
Here you can see the monitor as it is today, including the control panel that I also made from plywood attached to the bottom of the display.

This was quite a satisfying project, and while I appreciate that not everybody has access to these kind of tools, the actual process of converting a laptop display to a monitor is within most peoples abilities. Your choice of casing doesn't need to be as elaborate as mine. I hope you enjoyed reading about it as much as I enjoyed explaining it.

Thanks for reading. :)

You can download my DXF files here.

19 February, 2015

Vietnam Bug Juice

I recently found a single empty bottle in my camping gear and thought "That looks familiar", but I couldn't place where I had seen the bottle until I came across this image of proportedly real Vietnam issue bug juice from 1966.

image copyright sofmilitary.co.uk

So I decided to turn my almost identical bottle into a prop. This is my finished reproduction...

my reproduction prop
Which I think is close enough to pass the stand off scale test.

I used Inkscape to layout the text and printed on my thermal label printer onto white adhesive labels which I then cut down.

before I trimmed the label

This is how the bottle looks under my helmet band...

Thanks for reading this mini-post. :)

09 January, 2015

Rifle Rack Construction Method and Assembly

I have been asked for details on how I constructed my Easy Build Compact Rifle Rack. Here are some pictures that may help you make sense of the cutting process and the assembly.

A model of the finished rack

I started by cutting the basic parts from 20mm thick board. On the left you will see both sides cut from the same board. On the right you will see six parts all the same width. The top two are the top rail assembly, the bottom four make up the base assembly.

Note: For my American friends, I am sorry the measurements are metric, however most of them are actually multiples or fractions of an inch so it would not be too difficult to follow along.


Overall dimensions of the parts

 Here is a close up of the top rail assembly and the layout of the rail.

Marking out the top rail

 After cutting it looks like this.

The top rail after it has been cut with a jigsaw
 Next I cut the oval holes in the base plate. These holes must align with the top rail and be equally spaced.

Each hole is two 60mm diameter circles

After cutting it looked like this.

I cut the holes with a 60mm holesaw and a jigsaw

 The sides are cut from the same board.

Layout of the sides
After they are cut they look like this.

I cut the sides with a jigsaw.

With all the parts cut out they should look like this.

I also rounded over the edges with a round-over bit on my router table

In the next images I will show the basic assembly. So that you can follow along I have coloured each part.

If Skittles made rifle racks

I first assembled the base and the top rail. I used a biscuit jointer and glue. These could simply have been glued with the parts butted up against each other or possibly with dowels or even screws.

The base and top rail assembly

I then joined the base and top rail assembles to on of the sides, checking for square.

It is critical to check for square
Then the other side is joined, again checking for square. After it was all solid, I trimmed the front of the top-rail assembly flush with the sides. This could have been avoided by better planning at the design stage of these drawings.

Measure twice cut once applies even in the virtual domain

This is the actual finished piece. You can see it differs only slightly from the drawing.

My original rack dry fit (not yet glued)
I hope this short pictorial explanation will help you understand the construction of the rack.

Please be aware like all my blog these drawings are protected by the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

Thanks for reading! :)