Building a living photo frame with a Raspberry Pi and a motion detector | Hacker News Reader

Building a living photo frame with a Raspberry Pi and a motion detector

ofbrooklyn.com

58 pointsconesus16 comments

Nice project!

One tip for keeping the cost down - small LCD screens with composite inputs are available very cheaply on ebay (and elsewhere) if you search for rear view camera screens.

I got one for about half the price of similar units on adafruit. The viewing angle is terrible (as is the case on most really cheap screens) but the colour and brightness are great.

Somewhat related: where can I buy laptop-sized (13 inches and up) LCD screens that I can connect to a Raspberry Pi? I looked at eBay a while ago, and all I found was replacement screens for laptops, which neither have connectors that work with the RPi or backlight.

Edit: Of course I could just buy an ordinary LCD desktop monitor, but those are big and bulky. I'd rather have something slim and compact like a laptop screen, but without the laptop...

Most of the bulk in desktop LCD monitors is the power supply. Either find one that has an external supply or just rip that part out and use your own.

Great idea. Aside from the viewing angle are there any other differences?

The viewing angle is terrible

That's annoying but could be useful to get the viewer to stand in an intended path or spot to participate in some reactive art.

Great idea on the motion sensor, it would be cool to use HDMI-CEC to do something similar with a TV.

If anyone is interested I put together software[1] to do the slideshow piece on large format displays using a pi taped to the back. (I use my TV when it's not being used for actual TV).

[1] https://github.com/marwatk/pisaver

I have access to another Raspberry Pi that is used for a Gecko Board (fancy business status dashboard, with graphs and big numbers). I attached a motion detector (PIR sensor) to it and it runs the same commands to turn the HDMI monitor on and off.

The difference is that the HDMI monitor will turn itself off after 5 minutes when the HDMI port is turned off. That's why I also mentioned that you can just blank out the screen instead of turning of the `tvservice`, which will leave the HDMI monitor turned on but entirely blank.

    chvt 2

    tvservice -o

Has anyone found anywhere to buy enclosures for different RPi projects similar to this one? I have an RPi, a screen, and a project idea, but am struggling to come up with a way to make an enclosure for it that is at least passable.

Would the best way to just find a freelance 3d designer, and come up with specs?

There's a bunch of files on Thingyverse for 3d printed and lasercut acrylic/wood Raspberyi cases, most of which are quite readily opened and modified for custom projects. (I've got a file somewhere for a common 3d printed 'pi case which has been modified/extended to include a 4-ish inch lcd screen - intended eventually for a offline bitcoin safe…)

This sort of highlights a problem I've been running into. I have a prototype of a device I'm looking to build running with a Raspberry Pi, but I would love to use a BeagleBone Black for the advanced chipset features and greater power efficiency. However, I can't find any low-cost small screens to use with the BeagleBone. With the RPi, as mentioned by samworm, you can get cheap rear-view camera screens and they work just fine. With the BBB, you either need HDMI (and big and bulky cables) or find a screen that somehow plugs into the GPIO ports. These don't exist.

For the record, cheap and small is <$50 and <4" (>2.5"). Never been able to find one. It's a shame the RPi is so terrible, technically speaking.

http://hipstercircuits.com/finally-a-working-4-3-hdmi-compat...

0.3" larger than you're looking for but that isn't much.

I've actually got that link bookmarked, but I'm really looking for something I can buy and not have to build. I've tried "build it from a blog post" for something as cryptic as an HDMI display before, and it was a big waste of time and money when a critical step was left out.

Yeah you have to have a lot of engineering savvy to build stuff off blog articles and work out the missing bits.

I've built a few things this way including a complicated 20m transceiver and there are many pitfalls. Many a project ended up in the trash.

Aside from the hacking aspect, why would you build one using RPi and a small screen, when you could use a $50 tablet: http://tinyurl.com/atablets

Even motion detection is possible using the tablet's camera, no?

A PIR is a lot more energy efficient than continually doing motion detection. It's also a lot more accurate - it looks at Infrared rather than just movement (which can be caused by a moving curtain or flashing light, say)

But, yeah, why learn how to build something when you can just consume...

> But, yeah, why learn how to build something when you can just consume...

Let's not be so condescending. The tablet won't be an out-of-the-box solution; you'll still have to (a) either hack something out on Android, or (b) use a JS+HTML5-based solution. So you are building something, just not in the way the OP did.

Because you have a Pi available. Maybe you've moved onto other tiny computers (like Beagle Bone) or you just have one spare.

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