Hello

[robertvi]

Hi all,

Great forum! I don't have any workshop machines. I'm just starting to learn about this fascinating world, and maybe I will get myself set up with a mini-lathe and -mill one day This could easily become a lifetime hobby! So far I'm building a Stirling engine using tin cans and hand tools. About me:

A biologist by training (neuroscience, animal navigation, evolution, neural networks) I've mainly worked using computer simulations with Linux/C++ and Matlab, studying invertebrates. I also know some PHP, SQL and python, and started to learn AVR microcontrollers at some point.

Other current interests:
motorcycling, renewable energy (hence the Stirling engine)

Previous things I've built:
plastic bottle water rocket launch system, analog phototaxis robot (not my design), geodesic dome tent
- can you spot the common theme? me neither hehe

All the best,
Rob

PS: Brit currently living in New Zealand

 

[Tin Falcon]

Welcome . thanks for the into . These do help us help you.
Tin

 

[zeeprogrammer]

Welcome to the forum Rob.
I'd like to see pics of your tin-can engine.

 

[Maryak]

Rob,

Welcome to our forum. wEc1

Best Regards
Bob

 

[GordTopps]

Welcome wEc1 to the forum Rob

Best Regards from Sunny Spain

Gordy

 

[rake60]

Welcome to HMEM Rob.

Rick

 

[rudydubya]

Welcome Rob. wEc1 This is a great place to be inspired and learn about the hobby.

Regards,
Rudy

 

[itowbig]

welcome to the great place

 

[robertvi]

Thanks for such a warm welcome everyone. I will post pics of the tin can engine if it becomes a reality. Otherwise I will mostly be looking over the shoulders of the master craftsmen at work here!

 

[b.lindsey]

Welcome Rob,

I have seen some very nice runners made from nothing but cans and other simple material and they can be just a fun to build and run.

Bill

 

[mklotz]

Some examples...

http://www.boydhouse.com/stirling/

http://www.physics.sfasu.edu/astro/courses/egr112/StirlingEngine/stirling.html

http://www.modelengineeringsoc.com/Docs/TinCan.pdf

There are lots more. Just Google "tin can stirling" (note spelling of Stirling).

 

[wm460]

G'Day Rob,
Welcome to the forum from the centre of Australia.
Cheers,
Mark.

 

[student123]

Rob,

If I may add to the heat of the warm welcome - hello from the old country.
I studied genetic algorithms/neural nets/C++ also.
wouldn't mind a pic of the analog phototaxis robot - so I'll know what they are in case I meet one on a dark night!

Mike

 

[Brian Rupnow]

Hi Rob---Welcome. A few years ago I spent a day playing with plastic soft drink bottle rockets. It was a fun day. I found that #1---A 2 litre coke bottle will hold 100 PSI of air and not explode.----#2---with only air in the bottle, the bottle would expell all the air in one furious blast and only "lift" about twenty foot before falling back to earth.---#3 --with the bottle 3/4 full of water to act as reaction mass and 1/4 full of compressed air, I could achieve well over 130 foot of vertical travel. #4--an empty cole bottle falling from 130 feet will put a Hell of a dent in the hood of my wifes new Toyota.---#5 ---It is possible to have to lie to ones wife about things other than booze, money, or other women!!! ;D ;D ;D

 

[robertvi]

Here are photos of the (actually two different) robots. I think they're in a box somewhere at my parent's house in the UK right now, but were still working last time I checked.

I built these at a two day course organised by my friend Bill Bigge from Sussex University, using his designs. The whiskerbot is the most interesting:

It has six whiskers (just wire soldered straight onto the main board, with touch contacts either side of the central resting position to detect objects) and two light sensors. It's default mode is to 'waddle' forwards, alternately driving the left then right motor, but with a bias towards the side with the most light. Contact with the front whiskers causes it to reverse and turn. I think contact with the rear whiskers while reversing made it do something else too, like cancel the reversing. The overall impression was of a very fast but simple form of 'intelligence', a lot like an insect.

Natural selection very nearly eliminated this design the minute I had completed it - some guy arrived at the course with his child and asked me if my robot was 'ready to be born' - meaning could I please do something to keep his child occupied for a few minutes. The guy was actually only interested in talking to someone else in the room at the time, and nearly stepped on the robot (he was a 'larger gentleman') when I placed it on the floor and turned it on! It obviously needs some upward pointing whiskers connected to a fast forward response!

The second robot has a kind of general purpose analog brain, made up of several oscillator circuits which could be hooked up anyway you wanted with wire and resistors etc, and plugged into motors or sensors. I found that sometimes the oscillators seemed to be influencing each other even in the absence of wiring! (Bill thought they might have been coupled via emitting radio waves).

My robot built using the analog brain had the robot just move forwards with various 'gait patterns' depending on which resistors were connected if I remember correctly - it was impossible to predict what a given wiring arrangement would do.

 

[robertvi]

Brian, wow, hitting your wife's car

Those bottles are great little pressure vessels - I 'only' took mine up to 80psi. I pressure tested the bottle and launcher in my bedroom first - bad idea! I should have used the (much safer) method of filling it with water then adding a tiny bit of air to pressurise. The bottle, filled completely with 80 psi air, pushed itself off the top of the launcher and embedded itself in the ceiling with a loud bang :big: It punched a neat bottle-top sized circle though the plaster board. (The rocket had the top of a second bottle stuck on the front to house some weighting coins, to move the centre of gravity forwards.)

I don't have any pictures of this one. I remember the first successful launch (1/2 water filled) it went off so fast it left its rocket fins behind. After a vertical launch in light winds it landed 83 paces down wind - not bad!

 

[student123]

>and asked me if my robot was 'ready to be born'
Nothing like a technical question eh?!

Thanks for the pics. Looks like a couple of fun days - Well done with the robots.