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Andrius Kulikauskas Self Learners Network. Think Through Art with Andrius Kulikauskas. Directory of ways of figuring things out. Chicago Street Artist Blog. Video summary of knowledge of everything. Notes on Gamestorming. Living by Truth working group. Twitter: @selflearners Email: ms @ ms.lt
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AndriusKulikauskas January 2, 2008 15:11 CET I will be making some purchases for the Includer which I want to discuss with Ricardo and others who might have thoughts. My interest is that we be able to demonstrate the value of the concept and to experiment with optimal combinations. At this point I think price is a secondary consideration.
Money for purchasesI'm keen to get the Includer up and running, so I'm prepared to finance the initial purchases. I know you want to try the Gumstix. I'd like someone to try the Atmel AT91SAM9261 Microcontroller Evaluation Board and we could try other processors later as well.
Please let me know whether you want to buy several possible processors right at the start or buy and evaluate one at a time, to save money in case the first one is okay and we don't need an alternative.
A sensible way to proceed might be :-
Phase 1 - Gumstix, which has pre-loaded Linux (easier than a DIY approach).
a) Get Linux loaded.
c) Get a Java Virtual Machine, acquired, installed and working.
Phase 4 - Get a small number of prototype boards made, with components installed for us.
The short version... Just buy the LCD Pack [KIT0019], for $412...
It includes a ($60) netmicroSD-vx interface card that we don't really need, but it doesn't matter. It has Ethernet and MicroSD Memory Card connectors.
The longer explanation...
Please take a look at the summary of the Gumstix processors in Wikipedia...
They offer 3 different motherboards; Verdex, Connex and Basix.
Only the Verdex motherboard offers USB Host capability, the Connex and Basix don't have it and you can't add it via an expansion board.
Without USB Host capability, it's a show-stopper. We wouldn't be able to use a USB Keyboard and Mouse or control USB Slave peripherals, such as printers, modems, etc. Hence, we need a system with a Verdex motherboard. Neither of the pre-built computers (Waysmall and Netstix)) have these.
Plastic Case - The only case that Gumstix offers doesn't fit the boards supplied with the LCD Pack. See the case on the accessories page...
Hence, we will have to buy our own plastic case. Any online electronic component store will have one.
Spacers, screws and cables - These are supplied with the LCD Pack...
Interface to the Samsung LCD Panel - The LCD Panel just plugs onto a connector on the supplied consoleLCD-vx expansion board (some other boards make you solder the individual wires from the LCD cable to the LCD Controller expansion board).
Linux page, including Software Development KitThis page talks about using pre-built Linux images on the Gumstix, and lists the types of devices for which there are drivers.
Atmel AT91SAM9261 Microcontroller ready-built Evaluation Board
http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3820 Evaluation Kit.
Click the 'check distributor inventory' link for 'where to buy' and prices. Currently about $910 from...
http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3820 also has links to .pdf files for documentation, user guide, pcb details, etc. It's worth reading the user guide even before buying the kit. It has some good info.
The documentation even includes PCB layouts and Orcad computer-aided-design files, which may interest us later when we design our own small board.
See Mendenyo messages 823 and 824.Hub (for about $6) to expand the number of USB Devices. The evaluation kit has 2 USB Ports, but we need 3 to support a USB Keyboard, USB Mouse and USB Flash Drive.
A 256MB or better flash drive, perhaps a 1GB for $10.
Any standard USB Mouse, , from $6 upwards and a mouse-mat $1.
Display for developmentThe Atmel AT91SAM9261 evaluation kit already has a display (320 x 240 TFT), but we may want to try some others. See sections below.
Display directly controlled by AT91SAM9261 parallel outputs
See the info and link to a Sharp LCD Display in...
Here are some options...
1. Use a TV.
2. Any digital photo frame that takes composite video in via it's AV-In input.
3. A Portable DVD Player with AV In.
4. A computer with an AV In graphics card, to display TV programs. Many graphics cards have this now, just so they match their rivals cards.Includer in the final design, for maximum flexibility, and so we aren't dependent on a particular display being available.
Software to create an Includer on the Development KitIf we try out the AT91SAM9261 Evaluation Board, then we will need an operating system, such as the Linux that Atmel can supply, plus an application, such as an open-source text-editor. If we get the C source-code, we can compile it using the C compiler provided by Atmel for the AT91SAM9261. Linux, since it isn't a standard 80x86 processor, are we going to have to compile all applications for it from source and publish them on the net or flash-drive for people to use? It means people can't just browse the web for free applications, games, etc.
We want a very low-cost, very low power machine, so we can't really afford to blow the budget by using a 80x86 processor.
Java Virtual Machine' layer in softwareOne way out of the 'having to compile every app' problem is to provide a 'Java Virtual Machine' layer in software, allowing people to use any Java Application from the internet, without any extra compilation step. This could include the basic text-editor, email-editor and Wiki-editor applications. We can find some standard apps and write more suitable ones in Java if necessary, or get someone else to write them for us.
A 'Java Virtual Machine' layer makes a wide variety of hardware platforms appear like a standard hardware platform. This includes set-top boxes, mobile-phones, etc.
Wikipedia says "Java applications are typically compiled to bytecode which can run on any Java virtual machine (JVM) regardless of computer architecture". Hence, we or the users don't need to compile each application for the Includer processor.
It's probably best to try out the development kit or Gumstix etc first of all, then we can decide what else to buy and experiment with, such as things to make our own processor board - AT91SAM9261 or some other Microcontroller, a case, connectors, real-time battery-backed clock chip, etc. Atmel AT91SAM9261 Microcontroller has over 200 pins, so we would need the board professionally made and the processor mounted. I have a Bookmark to a UK firm that can do both (make the board and install components). There is a one-time setup cost, plus a cost per board. They can do small batches (1, 10, 100, etc), we don't have to order thousands.
PCB Train (UK)
http://www.pcbtrain.co.uk/ - Home Page.
http://www.pcbtrain.co.uk/onestepquote.php - One Stop Quote (online calculator)
I tried a quote for a board with the cheapest options (£1 = $2):
Type: 2 layer Plated Through Holes, 1.6mm thick.
Size: 125mm x 100mm (5 x 4 inches)
Delivery: 15 days
Cost per board: £4.00 without electrical test, £4.60 with test.
Assembly of components:
Circuit quantity: 100
Number of components per circuit: 20
Number of unique components or line items per item: 10
No. of BGAs (and QFNs) per circuit: 1 (BGA = Ball Grid Array, on processor)
Assembly unit cost per circuit: £17.24
Total for PCB + Assembly: £21.24
Possible cost reduction methods:
Higher quantities, shop around different firms, reduce component-count, reduce number of unique components.
At the moment, the Gumstix LCD Pack is out-of-stock and on back order. I think it said 'up to 15 business days'. When ordering, you need the European 240V AC to 5V DC power supply from the 'Accessories' page.
The Chumby looks an interesting Gizmo and a good example of open-source design. Were you thinking of using it as an Includer at all? I see that it's quite small in the photo next to a coffee mug. It's 5.5 inches wide, with a 3.5 inch TFT display. Also, are the USB ports USB Hosts? Without that, it can't read/write flash drives or control peripherals. If it does have USB Host capability then it looks an interesting device to play around with.
Things to do with the Atmel Evaluation Kit
1. Get a Hello World program working with the Atmel Linux and boot-loader.
2. Try some other displays, such as a simple 16 x 2 character display, via the 2-wire serial SPI interface, or an intelligent graphic display, controlled via a 2-wire SPI interface.
3. Get a USB to VGA adaptor box to use a VGA Monitor as a display. This would show the Includer could form the heart of a desktop PC-like system. The chosen box must have a Linux driver available for it.
You mentioned buying a digital photo frame. If this is to be used as a display-device for the Includer, please ensure it has AV-IN. Some also have AV-Out, so they can display things on a TV. One with AV-IN and AV-OUT could be used in place of buying a USB-to-VGA box at about the same price.
With a photo frame, you might like to try displaying some eBooks converted to JPEG pages. Some can display .TXT files. One expensive one I saw recently can display .PDFs. For JPEG eBooks and creating them using Primo PDF, see...
DVD Player - some have Video-Input that we might use somehow, perhaps to convert from one video-standard to another, such as composite video to SCART or something.
1. Please see my new Community Web TV page. It's a way to broadcast a 1-way rolling-carousel of useful web-pages and locally produced info, adverts, news, etc to people's TVs at home, via cable or TV. It's a cheap way to expose 100s of people to computers and web-info.
2. See the attached 'Data broadcasting by FM radio' document. I'm not too sure of the copyright of the photos, so please don't post it on the net.
Both projects are things that you and the chaps can do fairly easily. They are at the 'plugging boxes and cables together' level of electronics, plus some fairly straightforward bits of software that may interest you. They are things that can start simply in the Lab, but with a lot of growth potential. They may have some uses in Lithuania, not just in Africa.