13 Apr 2022
Inspired by Green Planet, in which some wonderful sped-up plant proliferation is captured, I’ve been working on a little hobby project. My very own “timeslap” (this is Finn’s name for timelapse, and I think it’s a big improvement).
I had been looking for an excuse to get a recent Raspberry Pi and try out the HQ camera module. My first idea was to capture the spring emergence of the leaves on the big lime trees outside our house, but a better opportunity presented itself: Mum and Dad have been having their garden “done” over the past few weeks. A small team of dedicated gardeners have transformed it from a rectangle of turf to (well, hopefully) a much more interesting and appealing garden.
At the start of the timeslap, I made a few back of the envelope calculations. Deciding on a playback rate of one week per minute, a framerate of 24fps and guessing that the daylight would last about 12 hours per day Mon-Fri, that’s 60 hours (3,600 minutes) over 24×60=1440 frames, or 2.5 minutes per frame. I plumped for a photo every 3 minutes. Over three weeks I could expect to take 3,600 photos during daytime.
raspistill I started capturing 12 megapixel images. Encoded as JPGs these were taking up 8.3MB, so I was looking at 8.3MB×3,600 - nearly 30GB. Manageable, but a lot. I’ve plumped for 1080 vertical lines for an HD picture (turns out the image quality from the £50 5mm lens I chose doesn’t really justify higher res). And, after “slapping” together a few days' of footage, results were promising but I realised I would want to chop out bits where not much happened.
I ended up with a nice long sequence, which is good but doesn’t make compelling viewing. So I did a bit of editing in iMovie, cutting out the dull parts, speeding things up a bit and adding a soundtrack.
I’m pretty happy with the results!
Tools used in the production:
- Raspberry Pi 4 Model B 2GB
- HQ camera module
- 5mm lens
- https://balena.io - can’t recommend their stuff highly enough
ffmpeg- the swiss army knife of digital video
- Amazon S3, EC2, lambda and heroku
- An old, cheap micro-SD card
- A “pro” micro-SD card, purchased in a hurry to replace the old, cheap one when it failed
- http://www.tickbeat.com for continuous success monitoring - picked up the failed SD card within minutes
- black cloth to hang up and minimise reflections from the window
- very patient and understanding parents
- consenting landscaping team, with diggers and all sorts
- and a nifty suction-based tripod arrangement (well technically it’s not a tripod because it doesn’t have any legs)
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