Housekeeping

We’ve been doing a bit of work on the maker space lately, and this website too!

For the last several years, our website has been hosted on a VPS provided by Blair (thanks so much!) Now that we’ve got a reliable Internet connection at the makerspace though, we’re able to host the site from an on-site computer that’s already hosting the Valley Workspace, Dunedin Electric Bikes, and Quarantine Island sites, and some makerspace affiliated projects like Dunedin food truck tracker foodoo.nz. If you’re interested in how the Internet works, want to host a site, or have fun ideas for things to connect to the machine, just say the word!

As part of the website move, I’ve upgraded the WordPress install, and am planning to embark on a clean out of the Users (we’ve apparently got ~45k) and Comments databases. I’ll try to keep from deleting legitimate accounts, but if your dspace account disappears, just let me know and I can restore it.

Finally, some donated lights were installed last weekend, in the room adjoining the bike workshop, to light up that web server!

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3D printing in commercial products

I was recently tinkering with a thing at work, and was surprised to find that a couple internal parts of this thing are 3D printed using a printer of the same type we’ve got at the makerspace!

This is a Thinklabs One digital stethoscope, available for sale online through mainstream retailers for about $500USD. Check out the grey plastic ring around the blue part.

3d-printed-part

Using the inductor tester

inductor tester
The inductor tester, and inductors used for examples below

A few weeks back, we had a talk on KiCad (presentation available at http://ianrrees.github.io/KiCad_talk/ ) where we ordered some PCBs to make an inductor tester (Henryometer?) from dirty PCBs. Those boards came in this week, and a few folks have already put theirs together. This post aims to be a quick guide to the usage of the tester; if you’d like to build one yourself just let Ian know, parts cost is $15. You’ll need an oscilloscope and a current-limited DC power supply to make use of it.

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Debugging AVRs (without Atmel Studio)

This post is somewhere between a guide and a collection of notes, aimed at debugging programs for AVR microcontrollers (like the ones in most Arduinos) “on target”. We’ll be using an AVR Dragon connected to the target micro via the normal 6-pin programming header, with a Mac or Linux PC as the host.

Although this is a bit more advanced than most of our other projects, it’s really quite approachable and is a very powerful technique for fixing AVR software problems.

From a high level; we’ll use a debugging program on a Mac (or Linux, Windows, etc) “host” computer, which communicates with a Dragon “In Circuit Emulator” (ICE) via USB to debug a buggy program running on the “target” AVR, which is presumably running in some circuit we’re interested in. Small variations might apply for Windows hosts, using JTAG instead of DebugWIRE, other debugger tools (Atmel JTAGICE mkII for example), etc.

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Arduinos and Macs

arduino

This evening, I finally got around to unwrapping the Arduino clone that came with my DSpace membership. Starting a project for the board couldn’t be easier, using the nice Arduino IDE from https://www.arduino.cc, but I ran into a little snag when it was time to upload the program onto the board. It turns out that these clone Arduinos use a newish low-cost USB to serial converter chip called a CH340G, rather than the FTDI brand chips used in the genuine Arduino boards. The CH340G that isn’t supported by MacOS by default, and I use MacOS, so the board didn’t show up in the Arduino application’s list of serial ports…

Fortunately, other folks have run into the same problem and have written up some nice blog posts on how to solve exactly this issue!

Moving

As you may have heard, the Dunedin Maker Space is getting ready to move to a new location in the Northeast Valley. The Allen St Workshop provides exciting new opportunities for the maker space including a concrete floor, collaboration with other like-minded folks, and there’s a fibre optic box out front!

We’ll continue to meet in the current King Edward College location as usual until 8 August when the move to the Allen St Workshop will commence. Stay tuned!

Sourcing RepRap parts around Dunedin

Things to note

  • Don’t get too hung up on bolt length. Get something longer than required and cut it down with a dremal or hacksaw.
  • Some reprap parts lists don’t include the extruder parts, so make sure you read what you need for those as well.
  • Please add comments for other places you have bought stuff or for things I need to fix.

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Electronics 101

I’ve included here the electronics1 talk I gave this week as a PDF

Remember the simple takeaways from this talk:

– the relationship between voltage, current and resistance – in particular bigger resistors mean less current

– capacitors pass AC and block DC

– inductors block AC and pass DC

– bipolar tranistors control a large amount of current with a small amount of current

– FET transistors control a large amount of current with a voltage

Please go and play with the excellent circuit simulator at:

http://www.falstad.com/circuit/e-index.html

try playing with resistors, current and voltage – and of course grab some and a meter at Makerspace and have a play

Week 2 talk electronics2 is also here as a PDF – transformers, diodes, power supplies, op amps and timers

 

Using solder stencils

I talked last week (April 18th) and gave a demo of using solder stencils to  make surface mount PCBs  and promised to post useful links.

I had my stencil made by Smart Prototyping ( http://smart-prototyping.com) – they offer stencils starting at $20 when boards are made (http://smart-prototyping.com/index.php?route=product/product&product_id=142)

Seeed (http://www.seeedstudio.com) also offer stencils for $70 (http://www.seeedstudio.com/depot/pcb-stencil-service-p-1391.html?cPath=185)

I ordered the stencil jig from AliExpress from: http://www.aliexpress.com/wholesaleproduct/wholesaleProductDetail.htm?productId=671199709&productSubject=NEW-stencil-printing-machine-24-30cm-Stencil-Printers-SMT-Stencil-Printers-manual-stencil-printer-with-solder – they come in a bunch of different sizes

I ordered my cheap reflow oven also on Aliexpress  from: http://www.aliexpress.com/wholesale?SearchText=t962&CatId=0&catId=

Stencils can also me made on a stencil cutter (http://blog.makezine.com/2011/11/01/solder-stencils-via-electronic-craft-cutter/ – google around there are lots of articles)