User avatar
mvnorwood
Raspberry Pi Certified Educator
Raspberry Pi Certified Educator
Posts: 73
Joined: Wed Dec 05, 2012 7:47 pm

Advice for a shower-proof time lapse wearable for Scouting!

Sun Mar 20, 2016 8:13 pm

Hi all,

I am planning on creating a project that will record hikes (I help with the Scout movement).

I want to attach a Pi Camera to the strap of a rucksack and get it to automatically take photos (say, once a minute) as I or a cub or a scout, take part in a hike. The idea would be to create a time lapse style film of the hike.

My plan would be to have a Pi attached to a battery pack (e.g the RAVpower portable charger) in a pocket of the rucksack. I would then have a long, long ribbon cable running down the shoulder strap attached to a forward facing Pi Camera board.

Obviously there are plenty of examples of how to code a project like this but I would like some hardware advice please.

These are the areas I would like your thoughts on:

- Which model of Pi would be best?
- What size of SDcard am I likely to need for a days hiking (if a photo a minute - or is that too many photos anyway?)
- What do I do about weatherproofing the camera board (the pi and battery will be straightforward and they'll be tucked away in the rucksack anyway)?
- I note that the Pi-Hut do a camera board mount for £3 can I adapt this to include a clip so it can be clipped securely on to a rucksack strap or is there a better solution?
- Does this camera mount provide any protection from the weather?
- Do long ribbon cables carry any disadvantages like data getting corrupted?

Any advice, help, sharing of your experiences would be greatly appreciated. Haven't done any stuff that needs weatherproofing before. Thanks in advance
Mark

ForToffee
Posts: 16
Joined: Tue May 29, 2012 9:05 am

Re: Advice for a shower-proof time lapse wearable for Scouti

Mon Mar 21, 2016 9:51 am

I like it! Get the young people to build it or use the images from the hike and you have the makings of part of the digital badges right there!

Pi - any would do. A+ has a lower power usage so would result in longer battery life, but if you have a large capacity battery then 8hrs on an original B is no problems.

SDCard - it depends on the image quality you capture at. Take a couple of images, have a look at the size then multiply up. Ultimately, bigger is better here

Waterproofing - I've seen numerous articles over the years for timelapse rigs. They often involve plastic tubs with a small hole for the camera lens, which is then covered with a clear film. The thin film you often find in food or toy packaging. That way the whole unit is sealed in, possibly with an additional hole for a power cable so the battery can be stashed in your bag.

By putting the whole setup in one small box you dispense with the need for camera mounts and the risks associated with long ribbon cables (corruption / entanglement).

Hope this helps. Let me know how you get on, it could become an official Scout resource!

Cheers

Carl

zealousd
Posts: 93
Joined: Sun Mar 20, 2016 10:57 am

Re: Advice for a shower-proof time lapse wearable for Scouti

Mon Mar 21, 2016 9:58 am

just take a hard case that will fit and you can seal and close it, mount the board inside and tape around the edges to air seal it. i have a case for the psp 1 which is metal which can fit the board and a battery pack and with the correct alterations i can make holes for cables and can seal with electrical tape.

As for the camera, mounting it on the outside sounds good but may not always get a clear shot as the bag will move side to side while walking so some testing may be in order.

connect a switch to the board and then run the cable so you can grab it and click, each click can activate a script that will run a camera snap? just throwing it out there.

just my 2 cents
Raspberry Pi 3
Ubuntu Mate
Web Server

User avatar
rurwin
Forum Moderator
Forum Moderator
Posts: 4257
Joined: Mon Jan 09, 2012 3:16 pm
Contact: Website

Re: Advice for a shower-proof time lapse wearable for Scouti

Mon Mar 21, 2016 10:08 am

Those ribbon cables are not the most robust things and you probably can't substitute another one because I think they are impedance-matched. I would mount the Pi with the camera. It will be heavier, but not too much so once you take the case into account too. You could tie it to the rucksack strap on the wearer's chest.

You might find these useful for connecting the Pi to a USB power-supply.

And this might also be useful in your quest: IP Ratings Explained.

And here's another couple of interesting links: the bodge-job and the professional.
http://www.richardmudhar.com/blog/2014/ ... h-weather/
https://tinkererblog.wordpress.com/2015 ... y-pi-case/

PiGraham
Posts: 4199
Joined: Fri Jun 07, 2013 12:37 pm
Location: Waterlooville

Re: Advice for a shower-proof time lapse wearable for Scouti

Mon Mar 21, 2016 10:50 am

Model A+ for size and power consumption.

USB memory for video storage for easy transfer.

Waterproof housing for an action camera, from eBay, for cheap waterproofing. This had the added benefit of waterproof button actuators built-in that you may be able to use to control recording.

The relative merits of the scouts making the thing vs. using it are for you to decide, but be aware that HD helmet cams with accessories, battery, waterproof housing etc are now available for Pi money (£30).
e.g. http://www.ebay.co.uk/bhp/hd-helmet-camera.

Bear in mind that the Pi/ PiCamera lacks audio input so you will have silent videos if you go that way.

An option would be to use a cheap USB webcam with a Pi Zero. The cable is better suited and you get audio.

User avatar
mvnorwood
Raspberry Pi Certified Educator
Raspberry Pi Certified Educator
Posts: 73
Joined: Wed Dec 05, 2012 7:47 pm

Re: Advice for a shower-proof time lapse wearable for Scouti

Mon Mar 21, 2016 1:44 pm

Thank you for all your excellent replies, very helpful :)

I have experimented this morning with attaching a pi (in a PiBow case) to a shoulder strap just to see how practical this kind of size would be (I wouldn't use a PiBow in the final project). I have found that the size of Pi on the strap is impractical and would get caught and pulled on things too often.

I think I will pursue my idea of having the Pi and power pack in the rucksack in an IP encloure with just the camera on the shoulder strap. Taking note of what some of you have said, do you think that an HDMI solution for connecting the camera might work better? Like the one here:

https://shop.pimoroni.com/products/pi-c ... -extension

It is a much more expensive solution than a ribbon cable but if people think it is more reliable then it may well be worth it :)

Thanks again for the help and let me know what you think.

User avatar
CaptSunset
Posts: 140
Joined: Fri Mar 20, 2015 2:55 pm

Re: Advice for a shower-proof time lapse wearable for Scouti

Mon Mar 21, 2016 9:37 pm

Just a suggestion, but your head may be a much better vantage point than the torso.

I'm fooling around with an old Stetson (cowboy hat), which will give you a mostly* waterproof environment, and everything needed can be mounted using Velcro. And... it keeps the hat on in a wind.
There are various possible positions for the camera module; if you are leading the troop even behind the head could be interesting.

*keep sweat in mind; better quality hats have vent holes for a reason.

User avatar
mvnorwood
Raspberry Pi Certified Educator
Raspberry Pi Certified Educator
Posts: 73
Joined: Wed Dec 05, 2012 7:47 pm

Re: Advice for a shower-proof time lapse wearable for Scouti

Mon Mar 21, 2016 10:48 pm

Interesting suggestion. Presumably you would mount the camera under the peak or brim of the hat.

Ideally though I would like a system that I could give to anyone to attach to whatever they walk in and everyone always has a rucksack but not everyone wears a hat :)

What do folks think of the idea of connecting the camera to the pi using an HDMI cable?

PiGraham
Posts: 4199
Joined: Fri Jun 07, 2013 12:37 pm
Location: Waterlooville

Re: Advice for a shower-proof time lapse wearable for Scouti

Tue Mar 22, 2016 9:09 am

Does sound matter to you?

User avatar
mvnorwood
Raspberry Pi Certified Educator
Raspberry Pi Certified Educator
Posts: 73
Joined: Wed Dec 05, 2012 7:47 pm

Re: Advice for a shower-proof time lapse wearable for Scouti

Tue Mar 22, 2016 2:36 pm

No I'm not interested in sound.

The idea is to record a whole days hiking using a still camera to take a photo every few minutes and then string them together into a short video reducing a whole days walking down to a few minutes :)

Does anyone have experience using the HDMI alternative to a ribbon cable?

User avatar
jbeale
Posts: 3725
Joined: Tue Nov 22, 2011 11:51 pm
Contact: Website

Re: Advice for a shower-proof time lapse wearable for Scouti

Tue Mar 22, 2016 11:36 pm

Yes the HDMI option works, and there are (relatively) thin HDMI cables that you can use. I have used that setup outdoors in a semi-permanent installation. Be aware this adds some volume because you need the adaptor board on each end, so I'm not sure if it's the best choice for a wearable, unless this is mounted on a backpack. To get 8 hours of RPi + camera runtime you need a USB "power-bank" of something like 21000 mAh capacity (that's what I have, and that's about the max runtime with Pi + Camera).

User avatar
mvnorwood
Raspberry Pi Certified Educator
Raspberry Pi Certified Educator
Posts: 73
Joined: Wed Dec 05, 2012 7:47 pm

Re: Advice for a shower-proof time lapse wearable for Scouti

Wed Mar 23, 2016 9:02 am

Thank you for that info, particularly the battery pack advice.

Looks like I will be using my large Anker pack rather than the RAVpower one.

PiGraham
Posts: 4199
Joined: Fri Jun 07, 2013 12:37 pm
Location: Waterlooville

Re: Advice for a shower-proof time lapse wearable for Scouti

Wed Mar 23, 2016 9:18 am

If it's only a single still image every few minutes you might consider using a tiny Arduino to power up the Pi on a timer to take a photo and shut down again. Even allowing that Raspbian takes 30s to boot you would probably more than halve the energy requirement.
Buildroot or baremetal boot much faster. 10 seconds running every 2 minutes could be more than ten times the runtime on a given battery.

User avatar
rurwin
Forum Moderator
Forum Moderator
Posts: 4257
Joined: Mon Jan 09, 2012 3:16 pm
Contact: Website

Re: Advice for a shower-proof time lapse wearable for Scouti

Wed Mar 23, 2016 3:38 pm

A minimal Raspbian install with no GUI could easily get down there as well. The idle process is usually not just a an infinite loop; it generally uses some sort of sleep mode, although I don't know the details.

PiGraham
Posts: 4199
Joined: Fri Jun 07, 2013 12:37 pm
Location: Waterlooville

Re: Advice for a shower-proof time lapse wearable for Scouti

Wed Mar 23, 2016 6:12 pm

rurwin wrote:A minimal Raspbian install with no GUI could easily get down there as well. The idle process is usually not just a an infinite loop; it generally uses some sort of sleep mode, although I don't know the details.
I'm sure there are many ways to get a Pi to boot in a few seconds. I've seen how quick buildroot can be in the form of the NOOBS menu and also Surveillance camera based on BuildRoot and Motion

Given the latter used the Pi Cam it might be a good starting point.

I believe Arch Linux boots much faster than Raspbian. Berryboot is worth a look.

gsh wrote:The fastest way to boot is to build yourself an initird ramdisk. That way you can be up in 5 seconds

Check out berryboot as an example of how quick it is to boot linux

Gordon

PiGraham
Posts: 4199
Joined: Fri Jun 07, 2013 12:37 pm
Location: Waterlooville

Re: Advice for a shower-proof time lapse wearable for Scouti

Wed Mar 23, 2016 6:16 pm

This add-on could be useful, although it would push your cost up.

MoPi

https://shop.pimoroni.com/products/mopi ... 0woddkgOnA
timer-based wake-up: tell MoPi what time you want your Pi to wakeup, then power it down and MoPi will boot the Pi as requested

Return to “Camera board”