Excellent information. Thank you for releasing all of this, I particularly enjoyed reading through the rainproofing as I am building a raspberry pi camera and there really aren’t any examples out there that I could find.
Show HN: I made a tiny camera with super long battery life
61–70 of 309 posts
Re: Show HN: I made a tiny camera with super long battery life
#62Earlier quoted context omitted.
Totally fair question! My reasons were: 1. To maximize Photon's battery life I tried to make the hardware do the absolute minimum to record imagery. To that end, Photon stores images on an unformatted SD card (ie one huge linear array of bytes) which is easy and fast to index into. 2. A 16-bit MSP430 handles writing the image data, and the MSP430's codespace is 99% exhausted without dealing with the complexities of a…
Can I ask why you went with a MSP430? I'm not judging, they were all the rage in low-power embedded applications 10-15 years ago, just feels weird to see it in a modern design today, when the market now is flooded with low-power ARM chips that are way more capable than that, and probably easier to program.
One main reason I chose the MSP430 was for the FRAM. Photon stores all its state (ie the photo ring buffer indices, and user settings) in one big FRAM struct, which can be read/written just like RAM, but persists across power cycles and crashes.
Another reason was MSP430's low power consumption, but like you said it sounds like ARM has caught up.
Would love to hear about alternative designs -- are there low-power ARM chips that have something like FRAM and don't require erase/programming dances to write data?
Re: Show HN: I made a tiny camera with super long battery life
#63Earlier quoted context omitted.
Totally fair question! My reasons were: 1. To maximize Photon's battery life I tried to make the hardware do the absolute minimum to record imagery. To that end, Photon stores images on an unformatted SD card (ie one huge linear array of bytes) which is easy and fast to index into. 2. A 16-bit MSP430 handles writing the image data, and the MSP430's codespace is 99% exhausted without dealing with the complexities of a…
Can I ask why you went with a MSP430? I'm not judging, they were all the rage in low-power embedded applications 10-15 years ago, just feels weird to see it in a modern design today, when the market now is flooded with low-power ARM chips that are way more capable than that, and probably easier to program.
Not the OP, but my understanding (admittedly a few years outdated) is that an MSP430 will, in idle, with sleep states properly set up and low power modes in use, drain a coin cell battery (e.g. CR2032) over a period of years - with the current drawn around 1.5 uA in standby and 0.1uA in RAM retention idle.
That is likely even lower than the effective self discharge rate of a lithium coin cell battery. I don't believe the Arm equivalents like the Cortex M0 can deliver such low absolute current - maybe microamps, but more than an MSP430 from what I can see.
Ref - https://metebalci.com/blog/measuring-the-power-consumption-o...
Re: Show HN: I made a tiny camera with super long battery life
#64Earlier quoted context omitted.
Totally fair question! My reasons were: 1. To maximize Photon's battery life I tried to make the hardware do the absolute minimum to record imagery. To that end, Photon stores images on an unformatted SD card (ie one huge linear array of bytes) which is easy and fast to index into. 2. A 16-bit MSP430 handles writing the image data, and the MSP430's codespace is 99% exhausted without dealing with the complexities of a…
Ok, so an app is needed to get the data from the device to a computer, and you wanted to focus your efforts on a "polished" Mac app. But why not make a non-polished Windows app as well? Or have someone make it? Also, is the RAW data specific to the device and if so, why? If the device simply used, say, DNG or TIFF, then decoding could be done by external software, and all your own software would have to do would be t…
> But why not make a non-polished Windows app as well? Or have someone make it?
If I had more time and money I certainly would!
> Also, is the RAW data specific to the device and if so, why?
To maximize battery life, the hardware does zero processing on the image data; it simply copies the raw pixels output by the image sensor to the unformatted SD card.
> If the device simply used, say, DNG or TIFF, then decoding could be done by external software, and all your own software would have to do would be to read the SD card and produce RAW files...?
True, perhaps I should've used an existing RAW format like DNG and exposed the images as a filesystem. That would require using a different architecture (ie not using an MSP430, like Rinzler89 suggested), and would likely reduce the battery life due to having to maintain a filesystem on the SD card.
Re: Show HN: I made a tiny camera with super long battery life
#65Would buy, but doesn't ship to Europe...
Re: Show HN: I made a tiny camera with super long battery life
#66Are there sample images from the camera on the product website? This is a neat idea but it would be nice to gauge to what extent it is fit for purpose, and a helpful way to do this is with a bunch of sample images.
I should definitely add some sample images...
For now, the Mac app has real imagery in the demo mode:
https://apps.apple.com/us/app/photon-transfer/id6476578040
(The demo photos are from the Lick Observatory on Mount Hamilton.)
Re: Show HN: I made a tiny camera with super long battery life
#67Earlier quoted context omitted.
Ok, so an app is needed to get the data from the device to a computer, and you wanted to focus your efforts on a "polished" Mac app. But why not make a non-polished Windows app as well? Or have someone make it? Also, is the RAW data specific to the device and if so, why? If the device simply used, say, DNG or TIFF, then decoding could be done by external software, and all your own software would have to do would be t…
> But why not make a non-polished Windows app as well? Or have someone make it? If I had more time and money I certainly would! > Also, is the RAW data specific to the device and if so, why? To maximize battery life, the hardware does zero processing on the image data; it simply copies the raw pixels output by the image sensor to the unformatted SD card. > If the device simply used, say, DNG or TIFF, then decoding co…
It seems it's the filesystem that's most costly? Would it be possible, maybe, to store DNG file data, one after the other, on the card, without a filesystem?
Re: Show HN: I made a tiny camera with super long battery life
#68Earlier quoted context omitted.
Totally fair question! My reasons were: 1. To maximize Photon's battery life I tried to make the hardware do the absolute minimum to record imagery. To that end, Photon stores images on an unformatted SD card (ie one huge linear array of bytes) which is easy and fast to index into. 2. A 16-bit MSP430 handles writing the image data, and the MSP430's codespace is 99% exhausted without dealing with the complexities of a…
It's pretty cool that your MSP handles the SD Card directly! Personally I think you should keep the focus on a polished mac app. For other platforms you can do just the bare minimum with a web app that uses WebUSB. People will bitch that it's Chromium only but, I mean, chromium has 95% market share outside Apple world (and I say this as a FF user). A hardware solution could be to add a cheap microcontroller that woul…
> It's pretty cool that your MSP handles the SD Card directly!
The MSP430 is actually the puppet master for an ICE40 FPGA that does the high-speed transfers (102 MHz) between image sensor -> SDRAM -> SD card.
Here's a post about the architecture if you're curious:
https://toaster.llc/blog/architecture
Thanks for the feedback!
Re: Show HN: I made a tiny camera with super long battery life
#69I'm not interested in the product, but I have to say this site is great. Too many sites that get posted in Show HN are so difficult to decipher what service they provide or function they serve. This landing page is about as clear as you could be straight away: it's a small camera -> great battery life -> pricing (without going to another page!) -> Mac Only -> Buy/Download links. You provide use cases, your tech specs are visible just by scrolling a bit, there's photos of the device that highlight its size. It even looks good. Only downside is a lack of example photos (which sound like they'll be added).
This is a breath of fresh air and I applaud your effort on it.
Re: Show HN: I made a tiny camera with super long battery life
#70Earlier quoted context omitted.
> But why not make a non-polished Windows app as well? Or have someone make it? If I had more time and money I certainly would! > Also, is the RAW data specific to the device and if so, why? To maximize battery life, the hardware does zero processing on the image data; it simply copies the raw pixels output by the image sensor to the unformatted SD card. > If the device simply used, say, DNG or TIFF, then decoding co…
It seems it's the filesystem that's most costly? Would it be possible, maybe, to store DNG file data, one after the other, on the card, without a filesystem?
I'm not too familiar with the DNG format, but if a DNG file could be as simple as [header][2304x1296x2 bytes][footer] then it might be possible with the current hardware.
But without a filesystem, would it be useful to have DNG files stored on the SD card? Wouldn't you need special software to read off the "packed" DNG data anyway? And if you need special software anyway, couldn't the special software convert the existing raw image data to the DNG format, instead of requiring the hardware to do it?