SARPi Project - Slacking on a Raspberry Pi

Raspberry Pi Model A Review

The Raspberry Pi Model A is the lower-spec variant of the current RPi family, with 256 MB of RAM, one USB port and no Ethernet port. Due to it missing a couple of ports and an Ethernet chip, the Model A consumes less power than the Model B or Model B+ and weighs slightly less.

It might seem odd that Raspberry Pi Ltd. would create a computer with only one USB port and no network (Ethernet) port. However, the Model A still has the S5 camera connector for the camera board, and the S2 display connector for a LCD screen. So there's much you can do with the Raspberry Pi Model A. Being lighter in weight, and using less power, means the device is better suited for weather balloonists who send them up into the high atmosphere, with a camera connected, to take pictures. The Model A with camera board is also favoured by those using it for time-lapse purposes because the lower power consumption offers an extended battery life for mobile applications. Raspberry Pi Ltd. have described the Model A and camera board as being 'natural bedfellows'.

You are still able to run Slackware Linux on the Model A, but you'll need to connect it to a USB hub to connect multiple USB devices. If you're planning on using it on the Internet you'll need a USB wireless dongle. With only having one USB port on the Model A and needing to use a USB hub to add more than one device, it can get a little untidy and you need a little more space in which to set it up. The Model A conveniently fits into the same case/enclosure as a Model B, being the same size and having the same form-factor.

If you're in need of a suitable Model A case/enclosure then look no further than Cyntech's range of Raspberry Pi Cases. They are ideal for housing (and protecting) your Pi, very robust, intuitively designed, extremely affordable, and look great!

You are able to purchase a Raspberry Pi Model A for around US $25 / GBP ~£16 / Euro ~€22 (ex tax).
NB: The Model A was supplanted by the Raspberry Pi Model A+ on 10 November 2014. (see this link)

Raspberry Pi top view
A Raspberry Pi Model A (top view - SD card slot is underneath)

Raspberry Pi Model A Hardware Revisions

There have been a few revisions of the Raspberry Pi Model A and the device can be any one of these variants. Depending on the hardware revision of the device, these subtle distinctions can include; different manufacturer and place of origin, and different manufacturer of RAM chip.

To find out the hardware revision of your Raspberry Pi(s), use this command, as 'root' user, at the command prompt:

root@slackware:~# cat /proc/cpuinfo | grep Revision

The currently available Raspberry Pi Model A revisions are:

HW Revision	RAM	PCB Rev	Release Date	Manufacturer
0007	256 MB	2.0	Q1 2013	Egoman
0008	256 MB	2.0	Q3 2013	Sony (UK)
0009	256 MB	2.0	Q3 2013	Qisda

Raspberry Pi Model A Spec's

Features:
• System-on-a-chip (SoC): Broadcom BCM2835 (CPU + GPU. SDRAM is a separate chip stacked on top)
• CPU: Broadcom BCM2708 700MHz ARM11 ARM1176JZF-S core (ARMv6)
• GPU: Broadcom VideoCore IV,OpenGL ES 2.0,OpenVG 1080p30 H.264 high-profile encode/decode
• RAM: 256MB LPDDR2 SDRAM @ 400MHz
• Secure Digital|SD / MMC / SDIO card socket
• Size: 86mm x 54mm x 15mm
• Power source: 5 V (DC) via Micro-B USB socket or GPIO header
• Power consumption: 300 mA, (1.5 W)

Connections:
• HDMI socket
• 1x USB 2.0 socket (provided by the BCM2835)
• RCA video socket
• Friction-fit SD card socket
• 3.5mm audio out jack
• Micro USB type B (power) socket
• General Purpose Input/Output (GPIO) 26 pin, Serial Peripheral Interface Bus (SPI), I²C, I²S[2], Universal asynchronous receiver/transmitter (UART)

For those interested further in the hardware side of the Raspberry Pi, see the RPi Hardware and RaspberryPi Boards webpages on eLinux.org.