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Robots & Dinosaurs is located in 10/27 Bank st, Meadowbank . We’re open Saturdays from about 11am and some weeknights, but you should check by asking on our mailing list.

Beco Blocks, the 3d printable, snap together, ball and socket based building blocks.

Initially created as a prototype for another ball and socket based project, these blocks functioned so well I decided to make a number of variations to allow the creation of more complex objects.

Beco blocks are great as toys and i suspect might also find practical applications for things like:

  • Light duty hinges.
  • Printable helping hands
  • Internal skeletons for soft toys.
  • Snap together bracelets.
  • Mini pose-able art mannequin

Beco blocks thus far have been printed on our Makerbot using ABS plastic. The first Beco block printed was very lonely, being the only Beco block in existence with no friends to snap together with. Some time later when I finally learnt how to use the Makerbot myself I started printing more, and was surprised to discover how effectively they clicked together. There were practically no design iterations in making the original male-female Beco block, i was just very lucky with a ball and socket size ratio which seems ideal. The 3d models for Beco blocks include struts which allow the printing of the ball in a horizontal orientation. The struts can quickly and easily be clipped off using light wire cutters. There is plenty of room for improvement in the design and additional brick variations. I have only designed enough types of bricks to build a basic figure so i hope others add to the collection. The STL files are available at Thingiverse here: http://www.thingiverse.com/thing:1983

Tinkering — November 14th

More tinkering again this Saturday.

  • We built a hot-wire foam cutter for the space, which should come in handy with our upcoming drumkit workshop.
  • Playing around with the BlueBoards we got. Congrats to Kean for solving the downloading problem.
Congrats to everyone for pledging for our new CNC Machine! We’ve reached our target in under 24 hours! I’ll put in the order tonight, and we’ll get this beast to us ASAP.

Geigerduino (part 1)

Over the last couple of months, Gav and R3becca have been discussing a new project idea - the Geigerduino. The idea being to be able to build an simple device that can detect cosmic rays or other radiation using a Geiger-Müller tube and an Arduino, and then publish the details so others could do the same. In late August, whilst having an R&D group dinner at Rockdale McDonalds, Gav quizzed me about generating high voltages, and I drew a rough schematic of a DC/DC boost converter (on a napkin of course). He told me the goal was to generate a PWM controlled voltage of up to 1000 V, using USB as a power supply. Having planted the seed, over the next two weeks I did some additional research and realised we should try a DC/DC converter using an isolated transformer with a voltage multiplier to get this kind of output. So, two weeks ago, we began prototyping this at the space. I built up a simple circuit on a breadboard, using a small transformer, some high voltage diodes and capacitors, and a MCP14E5 mosfet H-bridge driver chip. I had acquired a small batch of these transformers from a surplus electronics place a few years ago, and they seemed appropriate with a DC resistance of 11.5 ohms on the primary, and 2,300 ohms on the secondary. I had no other specs, but I think they were intended for generating HV to drive EL or CCFL lighting. The MCP14E5 is actually intended to drive the gate of power MOSFETs, but I had it handy, it is fast and can supply significant current, and it seems to do the job. I also needed a signal source to drive the transformer, and seeing as R&D had recently done a group purchase of Bus Pirates (preorder 2), I decided to use one of those. The Bus Pirate has a PWM generator mode that can generate 1 kHz to 4000 kHz signals with varying duty cycles.

gd1

So, what was the result - first we tried 1 low frequency, possibly 10 kHz, and got almost 500 V DC out.

gd2

A bit of tweaking, and we found that these transformers work best at around 50 kHz. This picture was taken when we were using about 8 V at 200 mA to drive the transformer.

gd3

Yes, we are generating nearly 800 V DC using USB and a simple breadboard circuit! Gavin and I then made up these circuits on some prototype PCB’s, and found we could generate 600 V DC quite nicely from USB power. Gavin even incorporated his Arduino DangerShield for PWM control.

gd4

There is a 10 M ohm load resistor on the output of the circuit. This provides some load (50 uA at 500 V), and helps to discharge the capacitors when the PWM is disabled. Be aware that many cheap multi-meters have an input impedence of only about 1 M ohm, and the load will drag the output voltage down below those shown above. Also, many meters and probes are not rated for use above 600 V (including the scope meter used in the photos!) Warning: Experimenting with high voltage is dangerous - both in terms of electric shock, and damage to your equipment. You have been warned. More to come… - Kean Reference material: http://en.wikipedia.org/wiki/High_voltage http://en.wikipedia.org/wiki/Boost_converter http://en.wikipedia.org/wiki/DC_to_DC_converter http://en.wikipedia.org/wiki/Voltage_multiplier http://en.wikipedia.org/wiki/H-bridge http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en531148 http://dangerousprototypes.com/bus-pirate-manual/

MakerBot Assembly Day! 5th September

The MakerBot Assembly Day was a rip-roaring success! Thanks to all those who attended and helped our bot crawl into life. It took us quite a few hours, and a little cursing, but eventually we’ve got the 3D printer moving and extruding to our hearts content. There’s a lingering bug with build ‘burping’s, but we do have to same something to work on for next weekend. Some higlights:

  • Max gave a demo of his quad-copter
  • Phi started work on a furnace
  • Adrian demod his ServoShield units
  • Jeremy gave a demonstration on how spontaneous symmetry breaking is done

Tinkering — August 29th

More tinkering this Saturday.

Thanks to Jason for kindly setting up the Wifi & Router for the space. That should come in very handy for getting data sheets at 3am.

Adrian was testing out his project, the Servo Shield for the arduino, which will be capable of driving 16 simultaneously.

In other news the MakerBot printer has arrived! Next weekend we’ll be assembling it together.

Tinkering — August 22nd

At it again with tinkering on the weekend. Some highlights:

  • We made some ferrofluid demonstration cells and gave them away
  • Set up a MythTV box, which will come in handy for our movie nights.
  • Bec’s project of welding up some brackets for a planter
  • Troubleshooting a Behemoth of an  Oscilloscope, kindly donated by Kean

Tinkering — August 8th

Another get together this Saturday. Some highlights

  • Chris gave his buffer overflow presentation, with demonstration code
  • Max did some experiments in underwater propulsion
  • Some tinkering with the R&D Robotic Jugband, the bellls work now!
  • Playing with high voltage Nixie bargraphs
  • 3D printing again
[gallery]

Tinkering — August 1st

We just had another Saturday get together in the space. Loads of people arrived and participated. It’s starting to get crowded in there! The R&D High Voltage Logo Some things which were playing around with include:

  • MakerBot 3D printing
  • The Robots and Dinosaurs Jugband
  • Tinkering with some servers and Xboxes
  • High voltage photography
  • Space maintenance
  • and a few other things
Tinkering with the Robots and Dinosaurs Jugband Status: This was a triumph!

Tinkering — July 25h

We had our usual tinkering get together on Saturday. Here are some of the things that happened:

* Chris & Anna decorated the walls with cool space invaders stickers!

Chris and Anna prepare the invasion

*Added a spiffy new doorbell to the space.

R&D Doorbell

* We got the 3pi robot working and layed out a quick course for it. It can follow lines and solve mazes. Surprisingly quick for such a little thing…

Robot Racecourse3Pi in action

* Gav & Ev got started with an optical theremin project. We’re using optical distance sensors to detect the location of the hand, then feeding the data to the PC as MIDI information

Rocking out the optical theremin

Plus a bunch of other stuff that didn’t get captured by my camera.