Posts archived in Hardware

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May 20, 2013

Cheap DIY Kwik-Cast

rg

I find WPI’s Kwik-Cast handy for some things around the lab. When we were modest users, the price didn’t bother me too much. However, when we started going through so much of it, I wondered if there was a way to buy it that fit our consumption level a bit better.

Both of those pots together were about $50. (Body Double Fast Set – Trial Size, Reynolds Advanced Materials)

rg2

These are the double-barreled syringes and mixing tips I bought. They’re from this company.
2mm x 8 Element, Needle Tip
qty. 1-99 – $0.91 each (WPI charges about $2.90 per tip, about 318% more)
qty. 100+ – $0.637 each (Buy 100 for $63.70. From WPI, 30 tips cost $87.00, 455% more)

4B19 Double barreled syringe
qty. 1-99 – $1.953 each
qty. 100+ – $1.367 each

Here, you can see below that the WPI Kwik-Cast kit uses the same syringes and mixing tips, at least as far as I can tell.

kwik-cast, click for source

From WPI, each of these syringes (with contents) is $85.

So you can buy the DIY stuff above ($50), 50 tips ($9.10 * 5 = $45.50), and 10 syringes ($19.53) for a grand total of $115.03. This would cost $850 + ($29 * 5 = $145) = $995.00 from WPI.

Plus, with the DIY way, you’ll still have the vast majority of your silicone elastomer left over from the $50 kit. I’m not sure I’ll ever run out.

The drawback of the DIY way is that you have to fill your own syringes, or have an undergrad do it for you. I used a couple of 5 mL syringes, and it took maybe a minute or two to do one syringe.

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February 11, 2013

Going back to Cali

calicode

No. I don’t think so.
Anyways, CaliCode is a resource for population calcium imaging. It covers topics from inferring action potential trains from imaging data (hat tip to JV), to image processing and topical papers.

P.S. If you get the reference, check out Game Rebellion’s version.

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January 16, 2013

EMCCD Specs

Editorial preface: Labrigger takes submissions from anyone. We post them if they’re potentially useful. In this case, we received some material from a commercial source. Labrigger is not endorsing their products. But we recognize that the people who are trying to sell cutting edge technology know a lot about it, and have some expertise to share. In this spirit, in the past Labrigger has suggested using catalogs as textbooks. This post is in the same vein.

Low light imaging with EMCCDs: what you should look for in technical specs

Written by Félicien Legrand and Sam Osseiran, Application scientists with Nüvü Cameras Inc

Compared to other low light imaging technologies, EMCCDs have the upper hand on several key detection parameters. They combine the high quantum efficiency (QE) and low dark current of traditional CCDs to the low readout noise of ICCDs to provide the best sensitivity in low light detection. However, in the harshest of lighting conditions, EMCCD performance becomes limited by a noise source referred to as clock-induced charges (CIC), which can contaminate images up to 200 times more than dark current in photon counting applications. Combine this with the excess noise factor (ENF), a coefficient related to the random nature of electron multiplication that effectively reduces signal-to-noise ratio (SNR), and you’ve quickly become limited in your photon counting abilities.

The good news in all this? Modern developments in EMCCD technology have allowed an appreciable reduction in all of the above noise sources including methods to eliminate the ENF and dropping CIC, leading to a great SNR – even in the darkest imaging conditions. Aside from the shot noise which is inherent to the nature of light itself, these modern commercial devices are getting closer and closer to what may be the perfect imaging device.

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November 21, 2012

50% off at Edmund Optics

If you’re like most people, you can get the vast majority of your holiday shopping done at Edmund Optics. They’re having a Cyber Monday sale this Monday, November 26th. Use code Cyber12 at checkout.

Here’s the deal, they’re offering 50% off of these product families: Clearance, Recertified, Anchor

The first two categories are self explanatory, but the third is an interesting product group so it’s worth a post to highlight it.

The anchor products (optics, mostly) come in different grades.
Commercial grade = meets stated spec
Experimental grade = up to 10% off stated spec

Grade 1: Normal, high quality product. Edged.
Grade 2: Chipped, stained, or otherwise slightly messed up. Not edged.

They’re already pretty cheap, so you can pick up a lot of optical elements for not much cash all in one go (e.g., protected gold 1″ diameter mirrors, $17.50 at Edmund’s Anchor section (and just $8.75 after the 50% discount), or $55.00 at Thorlabs). They’re not the highest spec stuff, but they’re not bad, and often the performance will be limited elsewhere in the system anyways. Grab some cheap items and mock something new up.

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November 6, 2012

Inventables: raw materials source

Inventables is a web retailer with a decent site that makes it easy to find raw materials and interesting components. E.g., stretch-sensing rubber and conductive velcro.

Inventables is to McMaster-Carr as SparkFun is to Mouser.

It’s run out of Chicago. Haven’t tried them, but probably will.

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October 5, 2012

Use 50 ohm BNCs, not 75 ohm

Coax BNC cables come in two flavors, 50 ohm and 75 ohm. For experimental rigs (PMTs, DAQs, amplifiers), always buy 50 ohm cables. The 75 ohm versions are for video applications, so they’re what you’ll typically find in consumer electronics stores.

The connectors are interoperable, so it can be difficult to tell what you have. The picture above should help.

In most applications, you won’t see much of a difference if you use a 75 ohm cable where a 50 ohm cable is supposed to be. But it is an impedance mismatch, and in some cases there will be a degradation of the signal. Just buy 50 ohm cables unless you’re doing something in video with instrumentation built to take 75 ohm cables.

When ordering: “RG58″ is a common type of 50 ohm connectors, and “RG59″ is a common type of 75 ohm connectors.

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September 28, 2012

Superbright LED spot

Lukas Fisher’s got a new post up covering the build of a super bright LED spotlight, including details on his experience with hotplate-based reflow soldering. (link)

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September 20, 2012

Scientifica’s 2p scope

With its newly introduced scan head, Scientifica’s 2p scope is finally a complete package. They’re happy to sell their modular design in pieces, so this fills the void between fully custom rigs and turnkey systems.

The scan head uses a relay lens system (a.k.a., a 1:1 telescope) between the x- and y- galvo mirrors. Most scopes opt to simply put the x- and y- galvo mirrors as close to each other as possible. The inclusion of a relay system is an interesting choice. Although not unheard of in 2p scopes or laser scanning scopes in general, I suspect they might become very popular for some fields of research. Here’s why…

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September 19, 2012

Nice enclosures

Most project enclosures are cheap and ugly. I challenge anyone to find something from PacTec that Dieter Rams would want in his house.

The following suggestions might not be Rams-worthy either, but they’re a step in the right direction.

Metcase
This company makes some decent enclosures (e.g., rackmount cases, nice knobs too)

PC cases
Recently I used some PC cases as project enclosures and was pleased with the results. For example, these fanless mini-ITX cases (pictured above) don’t have any drive bays, include some LEDs you can use to indicate anything, and aren’t terribly expensive.

HD enclosures
For something smaller, external HD enclosures aren’t a bad bet.

Previously on Labrigger…
Beautiful enclosure
Project enclosures

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September 11, 2012

A custom two photon scope on a wall

This isn’t an overhead view of the table, they just built the whole thing on a vertically-mounted breadboard. Cool. (link)

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