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Tiny Code Reader: a $7 QR code sensor
- cristoperb 1y agoThat's inexpensive enough to be the basis for a modern recreation of the CueCat: https://en.wikipedia.org/wiki/CueCat https://en.wikipedia.org/wiki/CueCat
- Ductapemaster 1y agoSadly, Useful Sensors seems to have pivoted to other edge AI tech and no longer sells this or their person detector.
- haarts 1y agoYeah, that is a shame. Couldn't find something similar unfortunately.
- ravetcofx 1y agoCan also do this with an esp-32 camera module which are cheap and all-in-one https://github.com/alvarowolfx/ESP32QRCodeReader https://github.com/alvarowolfx/ESP32QRCodeReader
- 123pie123 1y agoJust checked and the cost for a (non aliexpress) seller ESP32-CAM dev board is around £5-£6 or less than £1 from aliexpress
- waitwhat 1y agoAliexpress listings can have multiple different items, and the price displayed in the search results will be that of the first of those (in your case, probably just an antenna) rather than the actual item you searched for or even the item image shown on the results page.
- Neywiny 1y agoNot just the first, seems like the cheapest. I did a quick search and one result listed the second object's price, which was some permanent adapter board. But it's hard to fix such a thing. For example what if you really did want to buy another antenna for the device? Ok so maybe you require the listed price be the maximum. But what about like a raspberry pi kit where maybe you don't want the case or high capacity sd card or RAM, which could bring down the cost dramatically.
- dspillett 1y ago> But it's hard to fix such a thing. Especially when there is strong incentive to work around any such fix. Individual sellers do it deliberately often to make their listings appear more attractive, if this is "fixed" they'll find another way to be deceptive about the price that appears in searches, bitch & moan, or (much less likely) actually leave in favour of another marketplace, or some mix of the above. It is one of the reasons I simply ignore such places (others including delivery times and reliability: will I actually get the right thing that I think I'm ordering, or anything at all?) - yes, there might be genuine bargains to be had, but if you count the time and effort to find them amongst the deliberately deceptive listings, and the other concerns, I've found that I'm better off not bothering. It isn't just on marketplace type sites like AliExpress, Amazon, and such, it is also often done on individual sales pages in order to game shopping search engines like google's, though it is more common, to the point of being ubiquitous, on Ali and their ilk. One answer is that the individual products should be there own listing in the search so if I'm searching for the whole thing it is easy to see the price of that, same if I just want an individual part or add-on. If showing the lowest price, make sure any image is of that list price item not the more expensive one most likely being searched for. But that requires the sellers to properly file the listing details, and good luck enforcing that when they have competitive incentive not to. There is also the issue of very similar items: the same thing in different materials/colours/etc (things like 3D printer filament) where the price might vary. In that case perhaps an answer is to display a range on the search results ("from £x to £y") though that becomes a new problem to solve when the user selects to order by price.
- pseudosavant 1y agoI even found them on Amazon with Prime shipping for ~$8/each. Curious how challenging parsing a QR code would be with that?
- xmprt 1y agoMy experience with small QR code readers like this on ESP32 boards is that without a viewfinder, they lose a lot of utility. The feedback loop that a viewfinder gives with positioning and knowing when the QR code is detected is invaluable.
- nemomarx 1y agoI wonder if you could project some red LEDs instead, like barcode scanners?
- therein 1y agoYou can, and it still results in a subpar experience. There are products out there that do exactly that.
- Liftyee 1y agoIn places where QR payment is commonplace, readers without viewfinders often get round this issue with a pyramidal frame in front of the camera marking out its FOV, the rectangular opening indicating where the QR code should be aligned. From experience, the code often reads before you even finish approaching the reader.
- baby_souffle 1y agoAll of the cheap camera based two-dimensional barcode modules that I see on AliExpress tend to ship with a white LED as well as a red LED. The white LED is for general flood illumination and the red LED has some sort of pattern and lens array that keeps it centered in the cameras field of view and appears sharp and focused when the barcode is at the optimal distance. Camera detects motion, turns white LED and red LED on. Paper or screen with the QR code is now illuminated and humans can move up and down until the red Target appears in the center and in focus. Approximately a quarter of a second after that happens, you hear the beep noise indicating a successful read and decode
- benjaminbenben 1y agoIf you pair this with a eink display you could send messages back and forth with another device https://remotehack.space/QR-TX/ https://remotehack.space/QR-TX/
- degamad 1y agoGreat for bridging air-gaps....
- ruined 1y agopositioning limit may be a focus issue. typically on these cameras the lens is mounted and focused by a screw thread. there is not usually an 'infinity stop' because the mount is very simple, so i would expect the lens may be mechanically positioned outside the useful focus range. a 110 degree FoV is a very wide lens, so the useful screw range may be quite mechanically narrow, but when positioned properly it will have a very deep in-focus field, capturing near objects and far objects clearly. the datasheet doesn't say much about focus, but it looks like the rim of the lens is knurled for grip, so try rotating the lens. 'screw out' will bring focus nearer, 'screw in' will push focus farther. i would suggest indexing your start position with a paint pen for easy return, and then index the correct position if you find it. if all else fails, you could place a small aperture in front of the lens. this will reduce light transmission but also improve the focus field, like squinting your eyes.
- spicybright 1y agoA cheap android phone would perform better and for much cheaper.
- voidUpdate 1y agoWhere are you getting android phones for $7?
- spicybright 1y agoFree. Friends go through android phones all the time. You can pick up $20 ones new or cheaper ones on ebay or whatever. How are you getting the chip, micro controller, extra electrical components, breadboard/proto board, and power supply for $7?
- mananaysiempre 1y agoSomewhat incidentally, is there an actual description of how a low-tech QR code reader would work? I’ve looked for this a few years ago and all solutions I could find were of two flavours: (1) use ZXing (“Zebra Crossing”, a now-unmaintained library[1] for every 1D and 2D barcode under the sun); (2) use OpenCV. Nowhere could I find any discussion of how one would actually deal with the image-processing part by hand. And yet QR codes are 1994 tech, so they should hardly require fancy computer-vision stuff to process. [1] https://github.com/zxing/zxing https://github.com/zxing/zxing
- alex_suzuki 1y agoYou could have a look at the ISO spec on QR Codes to get the authoritative source on what kind of processing required. Alternatively (and what I would recommend), is grab a library that is dedicated to QR Code reading (I‘ve used Quirc, for example) and just read the code. Typically you threshold an image to get a binary representation (1: black, 0: white). Then you detect the finder patterns by looking for 1-1-3-1-1 runs of black/white. Once you have a bunch of finder patterns localized, you form triplets and decode the binary matrix that they span.
- cjbgkagh 1y agoI think many places roll their own. QR codes have a finder pattern of alternating black and white with relative spacing of 1-1-3-1-1 for any line that goes through the center of it. This has a low false positive rate so this step is the most important for performance. Since orientation doesn’t change the pattern horizontal scans are sufficient, once the center, scale, and rotation has been found the rest is fairly straight forward. There isn’t really a good reason why this set up couldn’t be rotation invariant, the processing power required is pretty low.
- jcynix 1y agoUsing https://duckduckgo.com/?q=qrcode%20decode%20by%20hand https://duckduckgo.com/?q=qrcode%20decode%20by%20hand gives me a number of results like http://blog.qartis.com/decoding-small-qr-codes-by-hand/ http://blog.qartis.com/decoding-small-qr-codes-by-hand/ https://beck-thompson.github.io/QRcodewebsite/ https://beck-thompson.github.io/QRcodewebsite/ Reading QR codes without a computer! https://qr.blinry.org/ https://qr.blinry.org/ And then there are a number of OSS implementations for Android (check fdroid.orgl, Debian/Ubuntu, etc. Maybe study the code?
- amelius 1y agoAnyone who knows of a cheap sensor that works in Linux and can read Digikey bag barcodes?
- MiguelHudnandez 1y agoI'm unclear about a specific sensor, but it looks like the format you want to decode would be "Data Matrix ECC 200" https://forum.digikey.com/t/digikey-product-labels-decoding-digikey-barcodes/41097 https://forum.digikey.com/t/digikey-product-labels-decoding-... I think a smartphone and custom app would be the worst case scenario in terms of cost, and that could be pretty cheap.
- unquietwiki 1y agoI've had a recurring idea in my head of a sensor you could mount in your car, and then be able to read QR codes from the side of the road, and get an index of all the businesses you'd be driving by for later lookup. Not sure how feasible or useful it'd actually be...
- ktallett 1y agoWould you genuinely want this? I personally can't see why. Perhaps at conventions it could be useful as it's hard to visit every table.
- avidiax 1y agoThat seems easier to do by using OpenStreetMaps and a GPS trace. You would need the businesses to cooperate by putting a QR code out, so they might as well cooperate and keep a maps listing up to date. I could imagine maybe OCRing the results from a line-scan camera. That would read all the business signs and street names as you drive by them.
- Too 1y ago”Attractions along the route” must have been a standard feature on satnavs since the very first standalone TomTom sucked onto your windscreen. Newer cars having Google Maps built in make this even richer.
- jcynix 1y agoWhy would I want to have this? No idea, but if I did I probably would use a modern dashcam (these can easily do 4K HDR with 60 fps nowadays) and later analyze the recording with OpenVC. Some viofo dashcams even allow the connection of two secondary cams (those only FullHD) so you could scan to the left and right simultaneously to the front.
- alnwlsn 1y agoReminds me of one of the ideas I heard about for how to do road navigation before GPS - you paint a bunch of barcodes on the road that your car reads as you drive over them, and then your computer figures out where you are (you would probably use dead reckoning with your car's speed and time, too).
- harrylepotter 1y agoA fridge-mounted ESP32 barcode integration would be pretty awesome for tracking fridge inventory
- jrexilius 1y agoI love these. Kinda insane they got it packaged so cheaply.