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My daughter would like to get involved with computers. I have heard that a Raspberry Pi is a good place to start. Her mother and I think that she would like to create a motion sensor camera so she can put it outside of the bird house she made. I found a couple of kits online, but since I don't have any idea what I am doing I thought I would give it a shot and ask for some help.

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    To be honest, if she wants to get into computing you don't need a raspberry pi (which is over hyped and the ARM hardware induces additional complexity). Just pick up an old computer and let her install Linux and play around with it. – user48917 Jul 3 '16 at 14:27
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    Completely agree with @AndréBorie. There's this bizarre notion lately that people can't get started programming with normal computers. Just get an old laptop or something - comes with everything you need and is portable too. – Matti Virkkunen Jul 3 '16 at 14:57
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    AFAIK you can make snapshots with motion detection with the standard raspberry pi camera tool. So you will just need the pi with the basics (PSU, maybe a case, maybe wlan adapter) and the camera. – allo Jul 3 '16 at 16:00
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    @AndréBorie I was a little torn about answering this because, as I say at the end, I think things may get a little frustrating for a ten year (there are certainly plenty of adults that show up here expressing such). But OTOH, learning via a Pi may grab a kid's interest more than simply plunking down a laptop with a bash and python tutorial. It's a gamble. If the parents are not already linux users, then they will probably have to be prepared to sit up a few nights, lol. – goldilocks Jul 3 '16 at 17:06
  • Thanks everyone for the help. This is a lot to think about. My wife and I will discuss where to go from here. We appreciate all the time and effort everyone put it. – njterps Jul 4 '16 at 21:06
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There are a few things in addition to the pi itself that are required, and if you do not already have them, you would want a kit that includes them. Generally these are appropriately priced, but depending on what is available to you it may also be easier to buy them separately:

  • Micro SD card. You can get these with an operating system pre-burned, but do not pay substantially more for the convenience. The OS is free anyway, and it is not difficult to copy an image onto a card -- also, this is probably something you should get comfortable doing as sometimes the quickest solution after having screwed something substantial up is to just start again from scratch.

    You want at least a 4 GB card and preferably 8 or 16, especially if you intend to take a lot of photographs or video on the card.

  • Power supply. 5V, 2-2.5A DC with a microUSB connector. Many devices (e.g., Android tablets) come with these, and supplies with slightly higher voltage are becoming increasing commonplace; this is probably a good thing but do not exceed 5.25V. Not all power supplies are created equal, and ones that are intended for charging may be marginal in the sense of not living up to their ratings; another culprit here are substandard cables, but this is not a difficult problem to solve.

    If you can't run an extension cord to the birdhouse, the pi can be run from a 5V power bank, but it is not as efficient as (e.g.) smartphones. A 10,000 mAh battery should be good for at least 4-6 hours (depending on the quality of the battery, it may last much more1), but beware in this scenario that letting the pi die from lack of power is not a good habit to get into. It will not cause physical damage, but it can cause filesystem corruption (a potential "start again from scratch" scenario).

    A 15-20W+ solar panel with 5V, 2A output is also a feasible power supply if you can be certain it is going to receive a good dose of sunlight, otherwise it will cut out on you.

  • Case. This can be improvised, and the board does have mounting holes, but considering there are many cases around for $5 or less, it is a good idea to get one built for the purpose. If you are going to use the CSI camera connector (e.g., the official Pi camera), make sure the case has a slot on top for the cable.

  • Wifi Adapter. The Pi 3 is the only model that has built in wifi, so if you are going to communicate using a different model in a birdhouse you'll probably want one (also, it is more generally convenient than an ethernet cable). Most cheap ($10-20), widely available adapters should be fine, but beware that manufacturers do not produce drivers for the pi, so this is dependent on one having been created by a third party. The linux kernel, which you will most likely be using, has this reasonably well covered, but there are still plenty of adapters around that can be troublesome. If you buy one as part of a kit, it is (hopefully) a safe bet. Otherwise I recommend getting one from a local store where it is easy to return something undamaged within a short period if it turns out not to work for your purposes.

I think you are best off with a quad core model (i.e., the Pi 2 or 3, aka. "2 B" and "3 B" but there are no other 2/3 versions so the "B" is superfluous). Other basic accessories useful in setting up and working with the pi are a USB keyboard, mouse, and HDMI cable for attachment to a monitor or TV.

With regard to the camera, you can use commonplace USB webcams but these can also be a gamble with regard to driver support; the official pi cameras (5 or 8 MP; beware there is a "no-ir" version which you do not want) are the best bet. The down side to these are 1) They require a special cable; generally they are sold with one 6-8" long but they are available in lengths up to 24", and 2) They are very small, delicate, and like the pi do not include an enclosure. There are cases available for them and they also have (very small) mounting holes. It is not particularly difficult to attach the camera inside a tupperware container with room for the pi itself, although you will want to drill a small (~1/4") hole for the lens.

I've done the above and covered the hole with a very thin layer of clear plastic (e.g, from some kind of packaging) epoxied onto the outside of the tupperware; this is fine since the camera does not autofocus, and if you compartmentalize the container with some bits of cardboard, styrofoam, etc., and use decent quality locking style tupperware, you can squeeze a pi with camera and powerbank into a fairly weatherproof, 10" x 6" x 2" box. If you are using this outside in the heat be sure to monitor the CPU temperature (there is a built-in sensor) via wifi; it is unlikely to be a problem, but the power banks generate additional heat and combining that with direct summer sun and no ventilation may not be a good idea.

Something else to consider...

My 10 yr old daughter.

I think this is a very minimal age for a project like this, depending of course on how tech savvy her parents are ;) I did teach myself BASIC on a VIC 20 at only a year or so older than that, but beware this is something that will take a lot of patience and probably involve a lot of frustration. A pi is substantially more complicated to use than a VIC 20.

In case my point isn't clear, beware you will not have a birdhouse cam at the end of the weekend kind of thing.

Of course, sometimes you don't need to actually catch the carrot on a stick in order to have fun and learn some things. I would emphasize the journey and not the goal.


1. The reason I've used 10 Ah as an example here is in general, if you want to do things this way and are shopping for a new battery, I do not think it is worthwhile buying anything smaller although in theory such a battery could last 20-40 hours (see discussion in comments below). I have not done a lot of research and experimentation this way, but I suspect a problem with many/most power banks is that as they run out of power, their voltage starts to fluctuate; this is fine if they are used for what they are mostly advertised for use as -- charging. However, with a pi, if the voltage dips below a certain point, it will stop working, and this may happen long before the battery is actually dry. Put another way: "Your mileage may vary".

  • Very well put, Goldilocks, as always – recantha Jul 3 '16 at 5:07
  • I agree this is a good answer, but a 10000mAh will last days. The 2A spec for the Pi refers to the peak consumption, an headless application with no mouse or keyboard requires less than a tenth of that. – Vladimir Cravero Jul 3 '16 at 15:31
  • @VladimirCravero You're right, it might, and that is a very conservative estimate (I'll add a reference to these comments). However, keep in mind that not all power banks are created equal -- I think they are notorious for using idealized ratings. The tupperware box I used was a few years ago, with a model B and a (debatable quality) 8000 mAh battery; that would last 3-4 hours (probably voltage drop as it ran out of juice) but of course, it also depends much on what you are doing. I did not have a USB ammeter then, but now I do I'll add a few observations: – goldilocks Jul 3 '16 at 16:53
  • That same B idling uses about the same current as my Pi 2 does while streaming half size, 30 fps video (~8 MB/s) -- 3-400 mA. However, that's over ethernet. Add a wifi adapter and I think you will be up over 500 mA. So a very liberal estimate would be 20 hours. Of course, if you are using motion or something, you won't need to be streaming video constantly, etc. – goldilocks Jul 3 '16 at 16:53
  • Anyway, the reason I said that about the battery is I do not think it is worthwhile trying this with anything smaller (unless you already own one, in which case you might as well); i.e., I did not want to recommend someone buy a 4000 mAh battery on the premise that it will last all afternoon because I am not so sure that will be true, and you might as well err on the conservative side WRT to this choice. – goldilocks Jul 3 '16 at 16:53

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