Comments for Brains in Jars

Comment on Build Log: Shaken Granular Laser by Geodesic Dome Studded With Cameras to 3D-Scan Anything Inside | MAKE

Geodesic Dome Studded With Cameras to 3D-Scan Anything Inside | MAKE — Thu, 24 Apr 2014 01:01:14 +0000

[…] DIY “shaken granular laser” in action. He now believes the consumer-grade laser used to excite the medium here is too […]

Comment on Selecting Random Items in Amazon SimpleDB by Zack

Zack — Thu, 23 Jan 2014 20:51:33 +0000

Ah, I get it now. Very clever. Thanks for answering this, I know it’s been a while since it was posted.

Comment on Selecting Random Items in Amazon SimpleDB by Kevin Loney

Kevin Loney — Thu, 23 Jan 2014 19:42:36 +0000

Hey Zack,

Normally you would be correct, however after selecting an item you assign it a new randomizer so even if there are duplicates they aren’t around for long. Since everything has the same probability of having a duplicate at any given time it does not skew the uniform distribution either.

It also depends on how long you make your randomizer string. If it is to short (e.g. There are more rows in your table then unique randomizers) then you will constantly have duplicates and some items will never be selected.

My personal preference for the randomizer string is to generate 128-bits of random entropy and then encode it in base64.

Comment on Selecting Random Items in Amazon SimpleDB by Zack

Zack — Thu, 23 Jan 2014 15:30:48 +0000

Hi! Thanks for this article, I believe it will come in handy in the project I’m currently working on. Question though: How are you generating the random string that you keep in your db so that you have no duplicates? Or do you have duplicates? I was thinking that if you had duplicates then there would be some items that would never get selected.

Comment on Linear Motion from a Rotary Actuator by Albert La

Albert La — Wed, 09 Oct 2013 17:04:47 +0000

Hi, this is Albert from Saskatoon Techworks. We met at Calgary Maker Faire 2013. I was wondering if you could send me the cut files for the lockbox mechanism and the coin sorter thing I saw at the space. Thanks

Comment on Linear Motion from a Rotary Actuator by Hackaday Links: Sunday, June 16th, 2013 | Make, Electronics projects, electronic Circuits, DIY projects, Microcontroller Projects - makeelectronic.com

Mon, 17 Jun 2013 16:55:58 +0000

[…] [Kevin] is trying to build a better reverse geocache box. It’s not the GPS that he’s improving, it’s the latching mechanism. He’s got four linear latches actuated by a single servo. […]

Comment on Linear Motion from a Rotary Actuator by Hackaday Links: Sunday, June 16th, 2013 | { Codeholics }

Hackaday Links: Sunday, June 16th, 2013 | { Codeholics } — Mon, 17 Jun 2013 05:02:20 +0000

Comment on Linear Motion from a Rotary Actuator by Hackaday Links: Sunday, June 16th, 2013 | Orange Claymore Red Slime

Hackaday Links: Sunday, June 16th, 2013 | Orange Claymore Red Slime — Mon, 17 Jun 2013 03:06:51 +0000

Comment on Linear Motion from a Rotary Actuator by Hackaday Links: Sunday, June 16th, 2013 | OPPATEC

Hackaday Links: Sunday, June 16th, 2013 | OPPATEC — Mon, 17 Jun 2013 02:01:06 +0000

Comment on Linear Motion from a Rotary Actuator by Hackaday Links: Sunday, June 16th, 2013 | Blog of MPRosa

Hackaday Links: Sunday, June 16th, 2013 | Blog of MPRosa — Sun, 16 Jun 2013 21:20:19 +0000