Quick Review: Raspberry Pi Model A+ & Official Raspberry Pi Case

A while back, I wrote a post for element14, and they offered to send me some goodies in return. At long last, they have arrived, so lets take a quick look at them.

Raspberry Pi Model A+

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When it comes to Raspberry Pis, most people end up buying Model B, B+ or Pi 2 B’s. It’s just natural that people want the 2 or 4 USB ports, Ethernet (or in the case of Pi 2, more cores and RAM).

However, if you’ve come towards the logical end of a project, sometimes what you want is lower cost, and lower power consumption – something that can just get the job done at a minimum. Often, these projects won’t even have a graphical desktop or unnecessary services running. Efficiency is the key, especially if you’re looking to go “battery powered”.

The original Model A wasn’t particularly exciting – it featured the same PCB as the B, just with some components unpopulated. When the Model B+ came out, I noted its lower power consumption as one of its key benefits, due to an upgrade to switching power converter components. The B+ was then overtaken by the Pi 2 B, which meant that the B+ wasn’t available for purchase anymore – and the old A consumed around the same power but without any Ethernet or USB.

Luckily, the Raspberry Pi foundation foresaw the demand for a lower powered, more efficient model, and thus introduced the Model A+. This is a new design based on “trimming down” the B+ board, and so is now physically smaller as a bonus. It is the lowest power consuming consumer-oriented Raspberry Pi model – and now I have my hands on one.

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A look at the packaging shows a fresh design with a different, rounded font. The side is coloured green to distinguish from the Model B’s which all have raspberry coloured spines. Despite the fact that this is still running the original BCM2835, this board seems to be here to stay, which is great news. This unit is made in the PRC, rather than UK, despite being shipped directly from the UK. I suspect this means the A+’s are mainly made in PRC.

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The box is a “thin box” and included is a thin quick-start guide and a safety instruction leaflet. The board is nestled in an anti-static bag.

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The board itself has the same height and common mount holes/port locations with the B+ and Pi 2 B, but is trimmed short. This makes it favourable for where space may be at a premium. It retains the efficient switching converter design introduced in the B+, as well as the 40-pin “hat-compatible” expanded GPIO. There are no loss of interfaces, be it audio, composite video, HDMI, CSI or DSI.

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The underside is nice and neat, with the microSD card slot being positioned where you would expect it to be.

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A quick tour of the board from all sides shows nothing out of the ordinary. If you’ve used a B+, or Pi 2 B, everything is where it should be, but you do only get one USB port rather than the 4 otherwise offered. This port is directly connected to the SoC’s USB port – but you are of course free to use a hub if you wish. Otherwise, maybe your project only needs Wi-Fi, in which case, you can probably pre-configure a card with a B+ and migrate that over, or you can interactively set it up first using a hub.

When I mentioned power efficiency as a key point, the numbers bear it out. With a not-so-accurate charger doctor, running the A+ registered about 150mA current consumption with a minimal set of background tasks. For comparison, a regular B consumed about 420mA, the B+ about 260mA, and the Pi 2 B about 280mA.

This represents a power consumption of just 36% of the regular B, 57% of a B+ and 54% of a Pi 2 B. Or in real terms, running from a power bank, you might be able to run your project from about 75% to 177% longer, although any peripherals attached will skew the figures and becomes a larger percentage of the A+’s consumption.

This is definitely good to know, and will help battery powered projects go that extra mile, and is precisely the reason I was looking for them.

Official Raspberry Pi Case

20151001-2132-5656Mid this year, the Raspberry Pi Foundation got their hands dirty in entering the accessories market for the Raspberry Pi by introducing an official case. All efforts to date have been third party jobs, so what does this new product bring to the end user?

For one, the Raspberry Pi Foundation seems to claim that the case is a work of beauty and functionality, so lets start by taking the plastic off and seeing just how it all “fits together”.

 

 

 

20151001-2134-5657Once you take the plastic off and turn it over, it looks pretty cool. It has a textured matte white top, with a curve to it. The Raspberry logo is clearly seen at the bottom, but looking at it from the top makes it look like a high-class wall-mounted thermostat (well, that’s what came to mind anyway).

But the case does have a few tricks up its sleeve. Like a nice white egg-shell, we must look inside to find the gold.

 

 

 

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Taking off the top layer, we find that there is a “raspberry” coloured jam layer in the middle. The cut-out over the board looks very much suitably apt for an LCD to show through, and the curved design almost seems reminiscent of a tamagotchi. Again, the Raspberry logo is in plain view. If anything, the contrasting colours kind of remind of strawberries and cream? Bread and jam? There’s more …

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… as that layer comes off too, to let us install the board itself. Wait a minute … just like a puzzle, this thing has even more pieces.

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Yes, the sides come off too! By now, you might be thinking, what’s the whole point of all this modularity with pieces everywhere? I mean, there’s nothing really special so far when it comes to mounting peripherals or making way for certain boards aside from the large top cut-out. Well, I have a theory – by making pieces interchangeable, part developers can probably bundle new panels for whatever “hats” or peripherals they want to incorporate. It also makes it easy for hobbyists to obtain the access they need to route cables and connectors, as they can simply remove the one piece and drill the necessary holes, and replace it – whereas a fixed case with moulded sides is more difficult to work precisely with. I think the design is definitely stylish, and the “puzzle” like nature actually does have benefits – it also means there’s no collection of haphazard cut-outs and slots for peripherals you’re not actually using.

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The underside comes with mounting points for adhesive feet, included, but strangely, there is no screw mounts or vent-holes, which might not please everyone.

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From the outside, we have light-pipe connected power and microSD activity LED holes, and microSD card access.

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The side panel does have some strange logos, for example, the power-on-off logo for the microUSB power port (I think a wall plug, or a lightning bolt of some sort is a better fit), and a camera logo for the composite video (a TV might make better sense).

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Cut-outs for Ethernet and USB are provided.

20151001-2137-5665And a blank plate for the GPIO connector side, which can be removed entirely for free access, or reworked to your desire. One thing this case will do is satisfy all those people who were angry that the new style third party cases were not available in raspberry colour.

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Installing the board should be a simple matter of sliding it in under the retention tang and setting it down. But unfortunately, my board didn’t fit! The reason became obvious on closer inspection – the light pipe for the LEDs was not correctly installed at the factory. As this part fits very snugly, I had to use a pair of pliers to ease it into position so that the pipe’s front edge sits flush with the body of the case, and the board would hence sit happily.

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No screws are used to secure the board, and instead, two raised standoffs protrude through the board’s mounting holes on the USB connector side to provide lateral support.

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In the end, this case does cost a little more than some of the other options, but it is definitely visually striking, somewhat elegant and appealing, and seems versatile and amenable to easier customization. Those who love the colour of raspberry need not look any further.

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Thanks element14!

About lui_gough

I'm a bit of a nut for electronics, computing, photography, radio, satellite and other technical hobbies. Click for more about me!
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5 Responses to Quick Review: Raspberry Pi Model A+ & Official Raspberry Pi Case

  1. mikiya says:

    I love your detailed reviews – including the Pi2 comparison from UK vs PRC (similarly, Pi3s are also quite different between E14 & RS). As parts change over time, I noticed the audio jack is different from your Pi2 vs Pi-A+ (also used on RS Pi3)…are there any audio performance differences? Also, is the ENIG solder finishing under the Pi-A+ (and RS Pi3) vs HASL tin finish under the Pi2 (and E14 Pi3) an improvement?

    • lui_gough says:

      Thanks for the comment – and oh I wished I had a reason to grab a Pi3 and a PiZero for that matter, but sadly, I don’t quite have the time or need for it just yet.

      I wouldn’t be surprised at parts changes over time – they may have had issues with one supplier or another, but more likely, they are trying to more aggressively source components, and whichever is cheaper probably means a little more return for the Raspberry Pi Foundation for them to put towards development. Technically speaking, connectors are connectors, and audio signals are pretty undemanding. The composite video signal is probably the one that’s more likely to have any negative impact due to impedance issues, but as few people use composite video, it’s a moot point. Audio-wise, the onboard audio is based off a pin which is PWM’d anyway, so audio quality was never too high to begin with. Just as some people will swear that pure silver or gold connectors “sound better”, the truth is that the undemanding audio signal really doesn’t care. The currents that pass are miniscule, the frequencies are not high like RF to require very specialized connectors with strict dimensioning – so as long as the plug is snug, and the contact is good, then it’s probably just as good. I haven’t had a chance to see nor test the plugs, but I can’t imagine they’d be too far off the mark.

      ENIG finish is normally considered more pricey, but ultimately, mostly equivalent for our purposes. Gold is nice because it doesn’t tarnish, is easy to solder to, and is relatively inert. This is good if you have unpopulated headers you might want to solder later, or you’re using some pads on a PCB as contacts, switches etc. because it is highly flat and regular. Tinned finish is not bad – it’s one of the most common depending on what type of soldering process is used, but can have some oxidation on the surface and in the case of older boards, can also contain lead which makes it less “friendly” to touch, although because of RoHS laws, modern boards are less dangerous. Functionally, they’re equivalent for most purposes, so I wouldn’t sweat the differences.

      – Gough

  2. mikiya says:

    Oops, got them reversed:
    RS Pi3 & Pi2 (UK): “open-top” audio jack, Tin HASL finish
    E14 Pi3 & Pi-A+ (PRC): “covered-top” audio jack, Gold ENIG finish
    Just wondering, as the audio jack was always a bit lacking (requiring products like hifiberry)
    If you ever do a Pi3 board comparison, it would be an interesting follow up trilogy
    Keep up the great work!

    • lui_gough says:

      The audio capability was lacking – that’s not to say the plug itself is the problem! The problem actually lies in the fact that the SoC has no dedicated sound-hardware at all – so instead, they made a “crude” but effective audio output by using a GPIO digital pin and “toggling” it between 0 and 1 very quickly (much faster than audio frequency) and then “filtering” that through some capacitors/resistors/etc to form a lower frequency “smoothed” output with limited resolution (to avoid consuming too much CPU resources, and within the limitations of the SoC itself).

      Add-ons such as the Cirrus/Wolfson audio card, Hi-Fi-berry utilize a dedicated digital serial bus (I2S) to transport digital samples to a dedicated analog to digital converter to produce a higher quality output, much more alike that of quality sound-cards and personal music players. The quality of the plug is not the difference – but a difference in the actual IC that’s generating the audio signal.

      – Gough

  3. mikiya says:

    Thanks for your informative reply! In recognition of your hard work, hope RPI foundation sends you a Pi3 & Zero in the near future 😉

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