Introduction

A friend said that with all the things I get up to, I should create a blog, so here goes.

Intro:
2 years ago I had a lot of time on my hands, so I built a Reprap Metric Prusa 3D Printer.
For details of Reprap, see here:
http://www.reprap.org/wiki/RepRap

My past work life includes: Electronics Assembly, Electronics Technician etc. So I can create circuits, Printed Circuit Boards and assemble them.

I have a pretty decent garage with a good tool set, pillar drill and lathe.

So, basically I have the tools and knowledge to pretty much build anything.
Above all else, I am a Biker in the old sense of the word: Try anything once. Never admit defeat. If it can be done then I can do it.
I'm also a great believer in the "F**k it attitude" and "If you can't fix it, f**k it, if you can't f**k it, use a bigger hammer". I do believe that when a project goes well, it can be "sexy", and things can be "perfect, but it will have to do".

Recent (completed) projects:
I have a daughter and 2 young grand children. Daughter says "Can you make a night light?", "Can you make a moon shaped night light?", 2 days later we have a moon shaped night light. Now I get "Can you make a Mickey Mouse shaped night light?" (for other grand child), 1 day later we now have moon and MM night lights, next I get "Can you make 2 more for when they stay at yours?", and "instead of moon, can we have Shooting Star?", you know it got done.
For these designs see here:
http://www.thingiverse.com/thing:267662

I am TrevM on thingiverse, you can get to all my published designs from the night light link.
These days I am a software engineer, my past life was all practical, build a PCB, wire up an electronic unit, all nice things you can hold in your hands, things you can look at and say "I built that", nice feeling. Software is different, you can't hold it, you can't point out the 'nice' design points etc., that part is missing.
Reprap introduced me to OpenSCAD, a neat application, basically, I write software to describe an object, then press a button and see that object, move it around, look at it from any angle on screen, with Reprap, I can then go further, a few button pushes later, I can hold that object in my hand. I confess to getting pretty addicted to it, just 'cos it was soooo much fun.
Making the printer cost £250 and took over a month to knock up. To keep 'her indoors' happy, I promised to create a new winch for her washing line. I soon discovered that I needed extra stuff to build a winch that were not available in OpenSCAD, that included threads and bearings.
So, my first ever OpenSCAD design was to create a system for ISO metric threads. Kind of as an after thought, I bunged it on thingiverse and was more than shocked at the fuss it caused.
The metric threads are here:
http://www.thingiverse.com/thing:27183
The finished Winch is here:
http://www.thingiverse.com/thing:28066
There are a few other quickie projects in Thingiverse.
I mention the threads because it was my first and still most popular, I mention the winch because it is big and strong (unusual in 3D printing) and it allowed me to build the printer in peace, I mention the night lights because it's my latest completed.

Current 'In Progress' projects:
Previous are all really quickie projects, these have taken a little longer and are a little more complex.

Jack Door
I have a little scamp 5 year old Jack Russel called Jack. Always well behaved, small dog, big personality. More of a teddy than a dog at home, turns into a wild creature on walks (doesn't want to be touched, examines everything with gusto) on walks.
We have 3 doors in our house. Front door he never leaves unless on lead. Kitchen side door and back patio doors lead to garden, he doesn't like using kitchen door, prefers patio door. Letting him out manually is a pain and leaving patio door open in bad weather is pretty dire. Cats use a cat flap, so I wanted a dog flap.
You can't buy a dog flap to go into a 6 foot (2 metre) square double glazed patio door. Or rather, you can, but it costs an arm and a leg.
So, I made one. it's basically a wood frame (same height as the aluminium door frame), painted similar colour to patio door and double glazed with perspex. Slide the patio door open, put the Jack Door section into the opening, latch it to the wall, the patio door closes and latches to the Jack door.
Here's a photo of the Jack Door in place:

Of course, life is never quite that simple. The perspex required grooves in the frame, the frame required shaping at the sides to mate with the frame and the patio door. I was thinking that maybe I had to shell out for a router, but my Dad had a 'plough plane', fabulous piece of kit, over a hundred years old, but did the job a treat.

Of course, 'her indoors' is concerned, wants it to ONLY work for our Jack. Jack is already chipped. Now most chip readers need to be in close contact with the dog. I think I have a design to produce a reader that will read his tag from up to 1 metre away. Idea being that I create some kind of controller, create some kind of electronic latch (I can't seem to buy one) and link it all to the reader.

But 1st job first, did the basic frame and fitted as above.

Now we find another snag. Cat's push open the cat flap with their heads, Jack simply won't!!!

So, the door is installed and instead of opening the main door, we can open the much smaller (much less draft) dog door, but increased thought needed.

I have an Arduino Leonardo Pro Micro ATmega32U4 controller (£3.32 off Ebay), fabulous bit of kit. I have that connected up to a self made driver PCB. Biggest headache was how the dickens do you open and close a dog flap under motor control? I now have a small 30 mm diameter, 40 mm long, 8 volt motor (£2 off Ebay), it connects to a printed PLA gear box (worm drive and other gears) mounted to the frame, that drives a large gear mounted to the flap. The interface board is connected to a remote control module and contains red, yellow and green LEDS and 1 button and all control housed in a printed PLA box. The flap now includes a printed PLA couner weight:

The counter weight is on the left, it is attached to the flap and hinges down with it. It is actually filled with 2 pence pieces. Ignore the wire wrapped around the bolt, that is the current way of latching the door open. The large half internal drive gear is attached to the right of the door.

This is the drive mechanism, the control box to the left, the motor and gear box to the right. In the middle are the 'open' and 'closed' limit switches. I still need to figure out how to mount the switches and create one or more suitable housings. But the box, remote control and motor all work when temporarily attaced to the door.

If door is open then press button and door closes, during close, red and yellow LEDs light on control box.

If door is closed the press button and door opens, during open, green and yellow LEDs light.

That all works, pressing any button on remote does same as pressing button on box.

The worm drive means that flap stays in end position, no electronic latches needed.

Motor and gear box are not over powered, the flap opens / closes in about 1.5 seconds, but can be easily stopped by hand (or paw or tail), so it is intrinsically safe (something that did worry me).

A more detailed picture of the gear box, motor attached to a small gear which drives small gear on end of worm, worm drives large gear, large gear is on same axle as door driving gear. Lid left off on purpose. It will also have a cover over motor, but that is finishing touch (later).

More detailed picture of control box and remote. Remote and receiver are RF, both purchased together off Ebay for £2.50. Button and LEDs are on other side of PCB.

This is the RF ID reader (to read Jack's chip), the big square is the aerial wound onto printed corners, it should fit nicely inside the double glazed flap, the small circuit board also gets mounted within the glazed section with 5 wires joining to main controller.

RF ID reader is normally not powered, once per second, controller powers it up and tries to read a chip. If it reads a chip and if it is Jack's chip then it will be considered a good read.

When closed then a good read acts like a button press.

When open then 3 bad reads act like a button press.

I have so far not tested this part, on paper it looks good, but I don't want to test on Jack, I have bought another chip from our vet, but I have misplaced it!

Besides, all the other jobs above have got in the way of completing this project, but it WILL get done.

Water proof box:

I recently changed my bike, old one was a Honda Shadow VT600C, it had a sissy bar (back rest) and mini rack, my water proof gear was bungied to it, ready to go, had the bike for 15 years, it rusted out. My new bike is a Honda Shadow VT750B, oddly, though same make a model, Honda in their wisdom have changed the style, the 600 was a cruiser, the new one is now called 'naked', it has no place to bungy anything to and I'm getting pretty bored with carrying water proofs inside a shoulder bag or even inside my jacket.

There are racks available, but pricing starts around £300 and they can go whistle.

So, I've printed a box, it's about a foot long, cylindrical, roughly 150 mm diameter. The box is here:

http://www.thingiverse.com/thing:27181

I'd like to spray paint it to match the bike, I'd originally planned to fix it above rear plate with tie-raps and rubber sheet, but I have so far not got around to spraying and I am now thinking that attaching behind seat may be a better option.

Still in progress.