raspberry picture

The Cost of Ownership

Part of the Raspberry Pi collection
by Douglas W. Jones
THE UNIVERSITY OF IOWA Department of Computer Science

A computer system typically includes a disk drive, a keyboard, a motherboard, a case, and the bits and pieces required to connect them all together. The advertised cost of a Raspberry Pi just covers the motherboard. Here is what I actually spent to get my Raspberry Pi system working:

Cost  Item  Source
$35.00 Raspberry PiModel B Allied Electronics
$ ?.00 Shipping USPS
$9.95 Kingston 8GB Micro SD HD Class 4 with adapter Retail over the counter
$12.50 Raspberry Pi Enclosure Kit Built-to-spec
$43.00 AT&T Laptop Dock for Motorola ATRIX 4G (used) Amazon
$6.99 Shipping USPS
$1.99 new memory card reader USB 2.0 adapter for sdhc sd mmc dailyappliance2010 (eBay)
$2.49 USB A male left angle to Mini 5 pin right angle adapter dailyappliance2010 (eBay)
$1.99 Micro USB B Male Female M/F Extension Charging Cable dailyappliance2010 (eBay)
$11.49 30cm HDMI 1.4 D type Micro HDMI Male to Female M/F
Cable for Motorola PHOTON 4G
daydaytrade (eBay)
$4.99 New Micro HDMI Female to HDMI Male Gold Plated
Adapter converter Connector
citycase (eBay)
$1.92 Angle Micro-B USB Host OTG Adapter Cable For
Sony Xperia S / LT26i
acj2103 (eBay)
$4.95 Shipping USPS
$4.99 Koolance 8x self-adhesive aluminum Video Card RAM
Heat Sinks - HTS-GP001P
Hellfire Toyz (eBay)
$142.25 Grand total

In general, shipping costs are listed immediately after the indicated item. The eBay purchases listed above are mostly cables and adapters needed to interface the Raspberry Pi to the Atrix Lapdock. I shopped carefully for all but one of these, they came with free express shipping from China. The exception was the Angle Micro-B adapter, where I discovered that I could not use the angle connector salvaged from one of the other cables so I needed another. Since I already had my Pi in hand at that time, I ordered for fast delivery of that cable instead of low price.

The heat sinks come in sets of 8, of which I need at most a few, and many would argue that I need none. For that matter, the enclosure I ordered is a luxury; I could have made one from Lego or printed one on a laser printer. The SD card reader is clearly optional if you already have one, but I did not. The used Atrix Lapdock was advertised as being in "as good as new" condition, and it was. I suppose I could have used the Pi with an old Mac keyboard and mouse, but as I have no HDMI or composite video monitor at work (where I would like to be able to use my Raspberry), or at home, where I could have used the composite input on a TV, I opted to buy the Atrix Lapdock.

I did not include some costs in my accounting above. The cost of a few inches of solder and the bits of heat-shrink tubing to create the Y connector needed to mate a Lapdock with a Raspberry Pi was excluded, and I did not count the labor to find the bits and pieces listed above. Actual assembly took 3 evenings, one to peel all the protective paper off the enclosure and then carefully wipe correction fluid into the lettering so it was readable, a second evening to make the Y-shaped cable, and a third to download Rasbian and figuring out how to copy it to an SD card. The machine booted flawlessly when it was all assembled.

I should note that I had no difficulty with the suppliers I ordered from through Amazon and eBay. Everything I ordered was delivered promptly on or before the date promised, and I got exactly what I ordered. When dealing with small fiddly connectors (micro USB), it is difficult to see that you're ordering the right connector -- and I made one mistake that cost me a week's delay and $5, discussed above.

Note that the new Raspberry Pi model B revision 2.0 board will not need the Y-cable for docking with an Atrix Lapdock; it can safely draw its power directly through the USB data cable. This is the same way that the Atrix cellphone that the Lapdock was designed for is powered. This will cut the effort needed for this kind of system configuration, and it will cut a few dollars from the price given above.

Posted Sept 5, 2012, last modified Sept 6, 2012.