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Tiny Raspberry Pi A+ SBC goes for $20

Nov 10, 2014 — by Eric Brown 3,510 views

The Raspberry Pi Foundation launched a Model A+ with a $20 price, and a tiny 65 x 56mm footprint, 23g weight, and compact 40-pin expansion header.

Despite its lower, $25 price, the Raspberry Pi Model A has never come close to the popularity of its newer, more feature rich sibling, the Model B. This summer, the B was upgraded to the Model B+, which kept the Model B’s $35 price, while adding several new features, some of which have been passed on to the now $20 Model A+.

Raspberry Pi Model A+
(click images to enlarge)

The Raspberry Pi Model A+ has joined the B+ in advancing from a 26-pin GPIO expansion connector to a 40-pin interface. As with the B+, the A+ GPIO array is backward compatible with previous add-ons, and supports the Pi Foundation’s optional HAT (Hardware Attached on Top) add-on board standard. HAT enables the Pi to automatically configure its GPIO signals and drivers for the board for a more plug-and-play experience.

Raspberry Pi Model A+ (left) compared to the original Model A
(click images to enlarge)

As with the B+, the A+ replaces the friction-fit SD slot with a microSD slot, and offers an improved audio circuit with a dedicated low-noise power supply. Like the B+, the A+ now has four mounting holes and rounded edges, and the new layout similarly aligns all ports on only two sides of the board.

Raspberry Pi Model A+ (left) compared to the Model B+
(click images to enlarge)

Almost as important for many hardware hackers is the reduction in size to 65 x 56mm, compared to the 85 x 56mm dimensions of the Model A and Model B+. The A+ is also lighter, weighing in at 23 grams — almost half the Model B+’s 45 grams.

Like the B+, the A+ offers lower, 600mA power consumption, down from 750mA, according to the Raspberry Pi Foundation. Along with the more extensive GPIOs, these improvements further the SBC’s usefulness in robotics, UAVs, and other space- and weight-constrained, motor-driven gizmos.


Like the other Pi models, the Model A runs Linux on the 700MHz, ARM11-based Broadcom BCM2835 CPU with VideoCore IV GPU. However, it stays with its modest allotment of 256MB RAM, half that of the Model B+. As before, it matches the B+’s HDMI, audio-out, micro-USB, and CSI camera ports, but it has no Ethernet port, and instead of having four USB host ports, it has one. As with the B+, the composite video port as been combined with the audio output.

Comparison of the four Raspberry Pi models

Model A Model A+ Model B Model B+
Processor Broadcom BCM2835 SoC with 700MHz ARM11 CPU and VideoCore IV GPU
RAM 256MB 256MB 512MB 512MB
Storage SD Card Micro SD SD Card Micro SD
A/V interfaces HDMI, composite video out, stereo audio out, CSI camera interface
USB 2.0 ports 1 1 2 4
Network port none 10/100 Ethernet
Expansion header 26-pin 40-pin (“HAT” compatible) 26-pin 40-pin (“HAT” compatible)
Dimensions 85 x 56mm 65 x 56mm 85 x 56mm 85 x 56mm

The smaller size and weight help the Model A differentiate itself from the B+. In the past, the $10 savings wasn’t enough for many to choose Model A, except for those working with certain embedded applications, especially cluster projects. Many of those applications are now better served with the $30, 67.6 x 30mm Raspberry Pi Compute Module. However, the Model A+ is now more relevant to hobbyist hardware hacking projects, especially in robotics, where real-world ports can still come in handy.

Summary of Raspberry Pi Model A+ specs

The following specifications are listed for the Raspberry Pi Model A+:

  • CPU — Broadcom BCM2835 SoC:
    • 1x 700MHz ARM11 CPU core
    • VideoCore IV GPU
  • RAM — 256MB SDRAM
  • Storage — Micro SD slot, for OS loading and data storage
  • A/V interfaces:
    • Full-size HDMI port
    • Composite video plus stereo outputs on 4-pole 3.5mm jack
    • DSI display port — compatible with the Raspberry Pi touchscreen display
    • CSI camera port — compatible with the Raspberry Pi camera
  • Other I/O — 1x USB 2 port
  • Expansion connector — 40-pin extended GPIO; “HAT” compatible
  • Power — +5V DC input @ 600mA, via Micro USB connector
  • Dimensions — 65 x 56mm
  • Weight — 23 grams debuts bigger, faster hacker SBC

While the Pi Foundation went small for its latest open spec SBC, its friendly rival went big. This weekend, tipped its largest, fastest hacker SBC yet in a 4.2 x 4.0-inch BeagleBoard-X15 that runs Linux on a new dual-core, 1.5GHz Cortex-A15 system-on-chip from Texas Instruments called the Sitara AM5728. No pricing was available for the board, which is expected to ship in February.

Further information

The Raspberry Pi Model A+ is available now, at $20 a shot, although in lower volumes than the B+. Sales are available at at MCM in the U.S. and Farnell in Europe. More information may be found at the Raspberry Pi blog.

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