Posts from the ‘Electronics’ Category
I recently ordered an Amazon Kindle 3G as I wanted an ebook reader to read papers and some of CommonsWare’s great android books and the kindle seemed like excellent value for money. It arrived today so here is a quick review along with some pictures:
Advantages
- Cost – Only ~£150
- 3G – Free browsing web over 3G (worldwide!)
- Wifi – For quicker browsing / downloading, works well no hitches.
- MP3 Player – With speakers or headphone socket
- Text to speech – So you don’t even have to read your ebooks any more, it even turns the page for you! The voice is quite good sounding only partially robotic; It manages pauses well with brackets, commas, etc. but sometimes doesn’t pause properly between paragraphs. Also some obscure words are mispronounced. I don’t know how good this would be for reading fiction as an audio book but this isn’t likely a feature I will be using much.
- Viewing angle – due to the technology of the screen (E ink), you can still see the screen irrespective of angle (unless view is physically obscured obviously…)
- – Screen is visible in direct sunlight unlike AMOLED phone screens
- Supported formats – Supports MOBI (kindle), PDF, EPUB
- Fits in my pocket – Just about fits in my pocket, with only a bit sticking out, this would obviously not be suited for long distance but as temporary holding place it is just fine.
Disadvantages
- White is grey – Okay so the background is not completely white, more greyish, but I don’t really care it is still very book-like.
- Scientific papers – Two column journal papers are a bit awkward to read or navigate using the current zoom settings
Neutral
- You could fit about 26,000 into a olymic sized swimming pool
Photos
Amazon kindle 3G reading a nice android pdf with images
Amazon kindle 3G (Experimental settings; Web browsing, mp3 player, and text to speech)
Newspapers
There is a choice of which country you’d like to view newspapers from and in the UK there is a choice of 5 (Telegraph, daily mail, independent, financial times, and London evening standard notably the Times is missing… what are they playing at?) all of which offer a 2 week free trial of the newspaper or the purchasing of single issues or a monthly subscription (prices vary).
Newspaper subscription on kindle (free 14 day trial on most subscriptions)
Daily Mail viewed on the kindle, no crossword or puzzle page though 
Microscope images
And as usual when I buy something new and exciting I have to look at it under a microscope 
Amazon Kindle 3G display (No mag)
Amazon Kindle 3G display under microscope (Low mag)
Amazon Kindle 3G display under microscope (High mag)
Fun with LED’s and liquid nitrogen
Working in a physics department has it’s perks. Below shows an orange LED changing colour as it is submerged into liquid nitrogen.
Many thanks to my house-mate for letting me play with liquid nitrogen and try this out.
I have been quite pleased with my previous microscope but I decided to buy a slightly better one from dealextreme as double the magnification was available for only a slightly higher cost.
product link) It only cost $48.20 USD (about £31.27 GBP) only $8 than my previous microscope that could only achieve 200x!
20X-400X 1.3MP Digital Microscope
20X-400X 1.3MP Digital Microscope with nice markings of the magnification
Quick Review
Advantages
- Large dynamic zoom range (labelled 20x – 400x)
- Easy to setup (plug and play)
- Can take some awesome photos, see below
- Variable illumination settings (using a wheel at top)
- Rubberised casing gives better grip and good overall feel
- Much improved build quality over the digimicro
- Stand is sturdy and can hold camera still in place
Comparison to the digimicro
Digimicro vs New Microscope
Comparison of microscopes at minimum zoom level
Comparison of microscopes at maximum zoom level
Magnification measurement
The images are taken with the edge of the camera case pressed right up against the ruler. You could probably remove casing to increase zoom slightly, or create a slot to slide a microscope slide into it. The camera has two focuses the first:
First focal point of microscope
And the second (maximum zoom):
Second focal point of microscope (0.5mm spacing between lines)
6mm displayed over 170mm: zoom ~ 30x
0.5mm displayed over 180mm: zoom ~ 360x
This isn’t far off the specified 20x – 400x so I am happy! (Note: Measuring magnification level is rubbish as it depends on screen the image is viewed on, so viewing it on a projector would make the statistics seem more impressive.)
The minimum zoom is less than this as we can move the camera further from the object
Setup in Linux
The beauty of this webcam is that it requires no installation with ubuntu 10.04 you simply need to run the software and the camera works! woo! The output of `lsusb` shows the device as:
Bus 001 Device 004: ID 0ac8:3610 Z-Star Microelectronics Corp.
Software
Most video programs will pick up the device, I am opting to use a program called cheese which is awesome not only because of the name but also because of its simplicity.
sudo apt-get install cheese
Bonus Picture
This is a photo of the pixels on a nexus one phone to show the pentile pixel layout
Nexus One Screen Under the Microscope
As before any requests for microscope images (within reason) will be considered
Whilst working on this post I managed to get some sexy shots of pixels in focus from my TFT screen under the microscope.
Regular pixels from a TFT screen
Cool Focusing on pixels from a TFT High magnification
More Cool Focusing on pixels from a TFT High magnification
After casually browsing this wikipedia article on google’s Nexus One (or HTC’s) I became interested in the AMOLED (Active-matrix OLED (Organic Light Emitting Device) screen due to its interesting pixel structure. Quote from wikipedia:
The Nexus One has a 3.7 inch AMOLED screen with PenTile matrix pixel arrangement. The raster resolution is 800×480 pixels, however each pixel in the PenTile RGBG display has only two subpixels (red and green, or blue and green alternately), rather than the three found in most displays. This gives it a total effective subpixel resolution of a 392×653 RBG display.[40]
So I decided to have a look under the microscope to see what I could find with my nexus one. Enjoy the following images:
Low Zoom
Nexus One's AMOLED screen under the microscope (Low magnification)
High zoom
Nexus One's AMOLED screen under the microscope (High magnification)
Nexus One's AMOLED screen under the microscope (High magnification)
Regular Pixel
Regular pixels from a TFT screen
**Update: New images from better microscope**
Nexus One Screen Under the Microscope
Short story: I received a free Nexus One (HTC) from Google for having an application on the android market with over 5000 downloads and a rating above 3.5 (For Counter-Strike 1.6 soundboard)
Nexus One unpacked, note the awesome android logo on the pouch
Back Story
Got a questionable email from Google (02/03/2010 23:47):
Subject: Device Seeding Program for Top Android Market Developers
From: android-market-seeding@google.comDue to your contribution to the success of Android Market, we would like to present you with a brand new Android device as part of our developer device seeding program. You are receiving this message because you’re one of the top developers in Android Market with one or more of your applications having a 3.5 star or higher rating and more than 5,000 unique downloads.
In order to receive this device, you must click through to this site, read the terms and conditions of the offer and fill out the registration form to give us your current mailing address so that we can ship your device.
You will receive either a Verizon Droid by Motorola or a Nexus One. Developers with mailing addresses in the US will receive either a Droid or Nexus one, based on random distribution. Developers from Canada, EU, and the EEA states (Norway, Lichtenstein), Switzerland, Hong Kong, Taiwan, and Singapore will receive a Nexus One. Developers with mailing addresses in countries not listed above will not receive a phone since these phones are not certified to be used in other countries.
We hope that you will enjoy your new device and continue to build more insanely popular apps for Android!
Thanks,
Eric Chu
Android Mobile PlatformGoogle, Inc.
1600 Amphitheater Parkway
Mountain View, CA 94043NOTE: You have received this mandatory email to notify you about an important update to the status of your Android account.
Initially I thought this was a scam, and searched the internet to check. Thankfully I came across a thread in Google forums of other people also sceptical about this email however it turned out to be legitimate (also confirmed by romainguy and others on twitter)
I then got a confirmation (06/03/2010):
Subject:Android Market Device Seeding Program Confirmation
From: Android Market Device Seeding ProgramDear Matthew,
We’ve received your information for the Android Market Device Seeding Program and have successfully validated the Google Order Number from your developer account.
Your information will now be sent to our shipping partner for order processing. Just to confirm, the information we received from you was:
Matthew RollingsIf you need to make any changes to your information above, please contact us at android-market-seeding@google.com as soon as possible. Otherwise, you should receive your phone in 2-4 weeks!
On behalf of the Android team,
Thanks, and happy coding!
Google, Inc.
1600 Amphitheater Parkway
Mountain View, CA 94043
I then received phone the phone on 29/04/2010 ~11:10. This is a lot later (3 weeks and 6 days) than the 2-4 weeks estimated for delivery, however this is believed to have been the fault of the shipping company Google were using.
Photos
Google device seeding nexus one letter
Nexus One box
Nexus One box with lid off
Nexus One, appologies for terrible photography skills
Nexus One handsfree earphones with logo
Note: I will probably update this post with better photos and photos of the phone in action, or possibly even give a review of how awesome the phone is (and also how to get the internet working on o2 UK).
As you may or may not be aware some printers add extra information in order for the printer to be identified (primarily for counterfeiting case I believe). With colour laser printers this can be in the form of a small array of yellow dots printed onto you paper. Yellow dots are hardly visible to the naked eye, however if you are close enough and get the light at the right angle you can see them. If you have some blue leds or a blue light available this can make it much easier to see the dots (as the yellow dots will absorb the blue and look black).
CUPS test paper with non-visible yellow dots
CUPS test paper with non-visible yellow dots (closer)
Now much clearer under blue led illumination:
Yellow dots very clear under blue illumination on the dell 1320c colour laser printer
Yellow dots very clear under blue illumination (zoomed in)
Unfortunately I my camera isn’t good enough quality and it doesn’t have a macro lens or feature so I can only show images at both extremes. Below are images captured with my microscope, you don’t have to look very far around the page, as the clusters are littered all over the page.
Microscope image of a few yellow dots on paper printed with dell 1320c
Microscope image of a two yellow dots (max zoom)
The Electronic frontier foundation have more information about the dots and have setup an address you can send a print test page to in order for them to build up a public defence case. Perhaps criminals will end up printing with yellow backgrounds to combat this method?
This is a nice colour laser printer that I managed to pick up quite cheaply with 2 sets of toner.
Problem
On my system (kubuntu 9.10 x86_64) it did not appear in lsusb and dmesg showed the following:
[15208.550014] usb 1-6: new high speed USB device using ehci_hcd and address 10
[15208.701200] usb 1-6: configuration #1 chosen from 1 choice
[15208.741575] usblp0: USB Bidirectional printer dev 10 if 0 alt 0 proto 2 vid 0x413C pid 0×5516
[15208.741596] usbcore: registered new interface driver usblp
[15209.747326] usb 1-6: usbfs: interface 0 claimed by usblp while ‘usb’ sets config #1
Funnily enough it did appear in the list of devices in virtualbox, however I had no luck trying (and didn’t really want to) to install it virtually. So I decided I’d make use of the built in network abilities of the printer and plug it directly into the router (I didn’t do this initially as I wanted the printer in a different room to the router).
Solution
After setting the printer up on the network, I ensure logged into the web interface and changed the password from the default. I then followed this thread on the ubuntuforums which refers to this text for installing the “Fuji Xerox DocuPrint C525A” driver which is compatible with the dell 1320c.
The driver is an 32bit rpm by default (which is fine for redhat based os’s), you can use alien to convert the rpm to an deb, or you can just download a prebuilt deb from zoffix.com (Direct link. This is a 32 bit package still so we need to install it using “–force-architecture”
sudo dpkg -i fuji-xerox-docuprint-c525-a-ap_1.0-2_i386.deb –force-architecture
Once this driver is installed you can login to cups and configure your printer as you would normally (instructions below). However when you are required to select the printer you need to provide the ppd file manually if you have installed the driver
1 – Open a webbrowser and goto http://localhost:631/admin
2 – Click add printer
3 – Enter a name for the printer eg: dell1320c (spaces are not allowed)
4 – Enter the printer address. This is the ip address of your printer prefixed with “lpd://”. eg: lpd://192.168.1.121
5 – Either locate Fuji Xerox DocuPrint C525A or select the ppd directly which is located at /usr/share/cups/model/FujiXerox/en/FX_DocuPrint_C525_A_AP.ppd
6 – Memory Capacity should be 64MB, and Optional Tray Module should be 250 Sheet Feeder
7 – finish.
Bypass tray problem
You should now print a test page, however if you get the problem like me that the printer always attempts to load paper from the manual paper feed, you will need to change the paper source from bypass tray to tray 1 in each program you need to print with (hopefully there will be a fix for this, but in this cups there seems no option to set it)
Select tray 1 to avoid using bypass paper with dell 1320c in ubuntu
Additional
I also noticed that this printer was covering each printed page with tiny yellow dots, which can be used to identify a printer (most likely for criminal matters).
DIY soil moisture sensors
I’ve been looking into creating an automated herbarium of some sort for a while, and I came across the brilliant post about creating some DIY soil moisture sensors using nails and plaster of paris. cheapvegetablegardener from hackaday.
Plaster of paris humidity sensor
Plaster of paris humidity sensor with wires attached
Both of the sensors
I wont explain all of the theory or background as it is already explained on cheapvegetablegardener.
Resistance experiment on moisture sensor
I measured the resistance of the sensor in air to be 12Kohms, I then placed the sensor into water (keeping the nail heads above the surface). The resistance dropped to 4Kohms whilst in the water, and then over 20 mins of back in air the resistance rose to 5.6Kohms. The sample still looks and feels quite wet, so I imagine it is going to take some time to dry, but from these prelimary results we can see it appears to work.
Soldering the wires to the nails before creating the plaster of paris along with covering the end sensor with hot glue would improve its longevity. I will post again once I find a better mould to make the plaster in as it was quite difficult to get them out of the cuvettes (I had about a 50% success rate).
Here is a microscope image of the surface of the plaster:
Microscope image of the surface of the plaster of paris
Measurement of microscope capabilities.
As requested (by uplink) here are some images and calculations of the microscopes maximum zoom.
The images are taken with the edge of the camera case pressed right up against the ruler. You could probably remove casing to increase zoom slightly, or create a slot to slide a microscope slide into it. The camera has two focuses the first:
Usb digital microscope's first zoom level of a ruler (markings at 0.5mm)
And the second (maximum zoom):
Usb digital microscope's full zoom level of a ruler (markings at 0.5mm)
I am using my laptop screen as a typical screen and viewing the image at 100%. Poor mans calculations give you the following for the first focus and second focus:
1mm displayed over 40mm: zoom ~ 40x
1mm displayed over 150mm: zoom ~ 150x
(Note: Measuring magnification level is rubbish as it depends on screen the image is viewed on, so viewing it on a projector would make the statistics seem more impressive.)
The minimum zoom is less than this as we can move the camera further from the object:
Usb digital microscope's minimum zoom level of a ruler (markings at 0.5mm)
Which is about 15x zoom. The microscope box states the zoom is between 10x and 200x, which from these tests seems a little over-exaggerated but not by much.
