20 ms·

Cat Printer

301 points by newman314 5y ago

snvzz 5y ago
Open printers of any kind are very welcome. I dream on an OSHW laser printer, engineered to be cheap, durable and easy to repair, with none of the bullshit manufacturers have been pushing on people for decades.
- spoonjim 5y ago
  I don’t know about repair but the $99 Brother laser printer doesn’t require any malware. You can print wirelessly from Windows/Mac/iOS without installing anything
  - lelandfe 5y ago
    If you keep an eye out, you can snag one for much cheaper on eBay! The one I used back in college was great, and I picked it up for around $40.
  - dylan604 5y ago
    I recently became much less enamored with my $99 Brother. There are certain paper types that it has issues pulling from the paper tray, but it can use it from the manual feed. However, the manual feed will not pull it straight and everything comes out at an angle.
    - tln 5y ago
      Interesting... what are you printing? I've had my brother laser for just about 10 years now, it's been awesome, regular paper, 80# cardstock and shipping labels being no problem from tray or feed. Envelopes haven't been great.
      - dylan604 5y ago
        Labels of various types that have specific places to print on the page is the issue for me. There's a test page that can be printed that shows alignment. The docs say to try something if it comes out skewed, but if that doesn't work then to take it to a certified place blah blah. It's clearly out of warranty, so that's a no go. I recently upgraded capabilities as doing more than could honestly be expected of a $99 printer. It has been well worth the expense of a higher model printer. Outside of that, I still love my $99 Brother B&W laser with scanner for anything not specialty labels. I look at it like not getting upset that a 1980s Yugo doesn't get nearly the same lap times as a 2000s model supercar
    - PaulHoule 5y ago
      If you get a cheap printer you have to buy expensive paper. I have the worst time printing in my house because the relative humidity level is very high in the summer. In the summer when my hair is curling and curling and curling from the humidity I have prints curling and trying to come off the walls. (In the winter I complain that static electricity is making my hair stand up on end.) You can't save money by buying 20 reams of paper on discount from Staples because the paper will soak up water and misbehave when you try to use it.
      - skybrian 5y ago
        Maybe a large plastic container and a desiccant would help?
  - newman314 5y ago
    Fun fact: did you know that you can netcat firmware to a Brother printer? It's both cool and terrifying.
    - denysvitali 5y ago
      Well, you can literally print a firmware on some printers, and it will install it. Not sure what's worse
    - vhold 5y ago
      See also: https://github.com/nmap/nmap/issues/2237 https://github.com/nmap/nmap/issues/2237
    - pabs3 5y ago
      Surely it would verify signatures before installing the firmware?
      - newman314 5y ago
        You would think so but no.
  - TheSpiceIsLife 5y ago
    $99 Australian dollars for second hand brother MFC-9330CDW colour wifi laser printer / scanner, needed new drums ($100 for the set of four) and one toner cartridge ($15), others are low but ok. Retails new for AU$550. $30 second hand monochrome laser printer at work I put by my workbench in a metal fabrication workshop, outside is filthy now, have run about 3000 pages through it, so about three toner cartridges, and a new. No issues. The software seems to be fine, light enough, unobtrusive.
- tombert 5y ago
  I find that giant office printers have given me a lot fewer headaches than "consumer" printers. I have a fifteen year old HP that I bought used on Craigslist for like $100, and it just magically worked upon plugging it into my router. I just use the generic Postscript driver on Macos. I don't think that driver is open source, but I suspect that you could fairly easily get a generic Postscript printer working with CUPS.
  - rhplus 5y ago
    Did it come with a hard-drive filled with copies of every corporate document it had ever printed?
    - tombert 5y ago
      You know, I don't know...it might? I never opened it up enough to look for a hard drive.
    - kingcharles 5y ago
      LOL. The amount of shit I've bought off eBay and Craigslist that hasn't been wiped is significant. And that's without being totally bogus and actually putting any effort into data recovery which would surely work on most devices. Phones were crazy. So. Much. Homemade. Porn.
      - gumby 5y ago
        > Phones were crazy. So. Much. Homemade. Porn. Any of it good?
        vangelis 5y ago
        Hopefully they did the right thing and factory reset it.
        kingcharles 5y ago
        Yes. I needed the phones clean. I had to buy up large numbers of random different handsets for testing SMS gateways.
- pabs3 5y ago
  Are there any printers with open source firmware at least?
tombert 5y ago
I wonder, if I wanted to recreate the Gameboy Camera with an emulator...has anyone done this with a webcam and a thermal printer? How hard was it?
- RL_Quine 5y ago
  Yes, emulators support the gameboy printer. In hardware it is implemented very close to the way the screen is written.
  - tombert 5y ago
    That might be fun then; have the emulator write to a thermal printer, relive a bit of nostalgia I have for the awful printouts of Pokemon characters I used to have (and might still have in a box somewhere actually).
    - _def 5y ago
      Next step: make a DIY gameboy printer that works with a real gameboy
- iamjackg 5y ago
  Most emulators are able to export a PNG that you could then print with something like this project! They don't support using a webcam with the ROM for the Game Boy Camera though. If you buy the real thing, there are lots of projects for extracting and printing the pictures though. This project implements a fake GB Printer that you can then access via WiFi to download the prints: https://github.com/zenaro147/NeoGB-Printer https://github.com/zenaro147/NeoGB-Printer This project I wrote a while ago allows you to use a printer very similar to the one in this submission as an actual Game Boy Printer, connected to an original Game Boy: https://github.com/iamjackg/esp32-phomemo-gameboy-printer https://github.com/iamjackg/esp32-phomemo-gameboy-printer
bitwize 5y ago
The perfect accessory to go with your bear computer: https://i.gzn.jp/img/2009/07/13/rilakkuma/rp_001.jpg https://i.gzn.jp/img/2009/07/13/rilakkuma/rp_001.jpg
- gardaani 5y ago
  The design is as cute as Nabaztag / Karotz: https://en.wikipedia.org/wiki/Nabaztag https://en.wikipedia.org/wiki/Nabaztag
  - boomboomsubban 5y ago
    The design is Rilakkuma, and seems to predate Nabaztag. https://en.wikipedia.org/wiki/Rilakkuma https://en.wikipedia.org/wiki/Rilakkuma
    - kingcharles 5y ago
      You're right: https://www.cnet.com/tech/computing/rilakkuma-netbook-the-best-computers-have-bears-on-them/ https://www.cnet.com/tech/computing/rilakkuma-netbook-the-be...
- ta8903 5y ago
  bear computer
jan_Inkepa 5y ago
I bought one of these because it was advertised as usb, but it being Bluetooth-with-special-(mobile-only!)app-only meant that I returned it. Nice to see someone jailbroke it :)
conroydave 5y ago
great now make it print github issues
- afandian 5y ago
  https://news.ycombinator.com/item?id=30803589 https://news.ycombinator.com/item?id=30803589
RBerenguel 5y ago
There’s also PPA6 for PeriPage thermal printers, a Python library using reverse engineering of the Bluetooth messages intercepted to the device: https://github.com/eliasweingaertner/peripage-A6-bluetooth https://github.com/eliasweingaertner/peripage-A6-bluetooth
ComputerCat 5y ago
This is absolutely adorable!
WoodenChair 5y ago
How would one go about reverse-engineering Bluetooth LE? Is it looking at packets through WireShark?
- ctoth 5y ago
  Using something like this[0]. [0]: https://greatscottgadgets.com/ubertoothone/ https://greatscottgadgets.com/ubertoothone/
- tyingq 5y ago
  Cheap device that can sniff BLE and send it to Wireshark: https://www.adafruit.com/product/2267 https://www.adafruit.com/product/2267 ($20) Overview on using it as a sniffer: https://learn.adafruit.com/introducing-adafruit-ble-bluetooth-low-energy-friend/ble-sniffer https://learn.adafruit.com/introducing-adafruit-ble-bluetoot... Still a lot of work though, if it's anything like LED signs I've reverse engineered. Trying to figure out if it's length encoded payloads or delimited payloads, what obscure checksums it might use, weird encoding of images, etc. And experimenting often hangs the device, or changes it's behavior significantly.
- tunaoftheland 5y ago
  Not reverse engineering, but I'd used free iOS/macOS apps that could inspect the traffic content. I also had access to the spec sheet from the manufacturer ("smart" BLE scale) that had where in the long payload digits were the weight, body fat, and water content, etc. Kinda fun and frustrating at the same time. If you truly wanted to punish yourself, you'd be doing this while trying to write a React Native app that communicated with the scale over BLE. :)
- anfractuosity 5y ago
  If there is an android app for the device, you can easily log the BLE data and load into wireshark https://www.mybluetoothreviews.com/what-is-bluetooth-hci-snoop-log/ https://www.mybluetoothreviews.com/what-is-bluetooth-hci-sno... shows how to capture the packets (you just go to the developer settings to turn it on)
rosstex 5y ago
Well that's the fastest I've purchased anything in a while.
sho_hn 5y ago
I just bought a Phomemo D30 thermal label printer to label my electronics component boxes last week, and I was wondering if I can hack things to send it images from my PC instead of the phone app it comes with. I found this repo, but I don't know if that's compatible with the D30 (the chassis pictured is of a different printer): https://github.com/vivier/phomemo-tools https://github.com/vivier/phomemo-tools Someone in Issues asked the same question, but the author wasn't able to answer for lack of hardware. I guess I need to try and/or contribute! The "Print master" phone app is uploaded under a different brand name (QUIN LLC), and other brands also seem to sell a D30 printer. I didn't really do the work of finding out where these truly come from. Perhaps someone's got a repo up under a different name. I've done 0 comparisons to other models in practice, but FWIW it does what I wanted it to do very well. All my stuff is obsessively well-labeled now. In fact, I labeled the printer in a mad-with-power move ... https://eikehein.com/stuff/label_printer.png https://eikehein.com/stuff/label_printer.png
- zwass 5y ago
  I actually just picked up the exact same printer but hadn't yet had time to see what OSS libraries were available yet. I had a previous project where I printed photos on a low res thermal printer. The images sucked, but people loved it.
vageli 5y ago
I would love to learn more about the reverse engineering process for a bluetooth device like this. It's too bad there is no link to a blog or additional documentation in the repo.
- szundi 5y ago
  You can buy a Nordic Semi usb devkit and their software can sniff. Maybe you can have the Android sw run in a virtual device and catch api calls
- Karliss 5y ago
  The repo states that they reverse engineered the Android app. So potentially 0% BLE specific reverse engineering and 100% of android Java. In some cases reverse engineering java code, which decompiles relatively well, can be easier than trying to sniff bluetooth packets, potentially dealing with standard bluetooth encryption and guessing what the raw bytes do.
  - packetlost 5y ago
    Can confirm, reverse engineering Android apps is decently easy if you aren't afraid of manually parsing Java bytecode (it's not that bad). I tried to reverse engineer the encryption/decryption mechanism for a digital book app (it was garbage, and I just wanted to read my books in a nice app :( ) and was almost successful.
- bilkow 5y ago
  You can decompile android apps, which will give mostly the original Java Classes / functions with anonymized names (class A, function b, etc...). Framework classes and methods usually stay pretty much the same. See for example https://github.com/robertohuertasm/apk-decompiler https://github.com/robertohuertasm/apk-decompiler and https://github.com/vaibhavpandeyvpz/apkstudio https://github.com/vaibhavpandeyvpz/apkstudio (only used the first one but the seconds looks practical)
ursaspark 5y ago
looks like this is a variant of the other "portable mini thermal printers" available on aliexpresss https://www.aliexpress.com/item/1005002247175933.html https://www.aliexpress.com/item/1005002247175933.html possible these are compatible or at least similar enough, many similar products re-use modules and microcontrollers.
- Karliss 5y ago
  Did anyone else notice that title of word document in the second product image is "From spyware with love"?
  - wolfgang42 5y ago
    Searching “Cow Tipping Championship in Vegas” eventually led me to this page: https://web.archive.org/web/20061117144904/http://www.spywarebiz.com/spylove.htm https://web.archive.org/web/20061117144904/http://www.spywar... Though how a 2005 blog post from a website selling antivirus software ended up being used as mock copy in a product photo is still a mystery to me...
ellisd 5y ago
I'd love to print to a Cat Printer from an iOS device via AirPrint. I see a ton of AirPlay to CUPS projects on Github, but I'm not quite sure how CUPS would be configured to simply call the Cat Printer python script. Any pointers on how to leverage CUPS or should I simply focus on an AirPrint server that directly calls Cat Printer?
- bo0tzz 5y ago
  I would take a look at https://en.opensuse.org/SDB:Using_Your_Own_Backends_to_Print_with_CUPS https://en.opensuse.org/SDB:Using_Your_Own_Backends_to_Print.... Going off a quick glance at the code examples, I think it might be fairly straightforward to hook into CUPS. https://github.com/jsmeix/cups-backends https://github.com/jsmeix/cups-backends also has some useful looking tools.
- kayodelycaon 5y ago
  It’s pretty easy to add backends to CUPS. They are just shell scripts. I’ve written a few ruby ones. Here’s an example of one I adapted for my own purposes: https://ofosos.org/2018/10/22/printing-to-remarkable-cloud-from-cups/ https://ofosos.org/2018/10/22/printing-to-remarkable-cloud-f...
pnemonic 5y ago
Lol'd at "Mean Threshold:" and then Grumpy Cat.
OJFord 5y ago
This is quite a tangent on label printing in general, but what I really want is a computerised label printer that does mechanical punched labels, like the classic Dymos and knock-offs. I still have and use one, basically because I don't use it enough that I need an electronic one, it'd just be handy, but I can't quite shake the appeal of the ~85% fully formed raised lettering.
ilaksh 5y ago
Does anyone know how the printhead elements are able to heat and cool rapidly enough? Is it just a very thin amount of a particular alloy and a precise amount and duration of voltage? Especially the cooling off part seems like it would require a really specific material. Unless all of the heat is someone removed as the paper scrolls.
- kingcharles 5y ago
  https://en.wikipedia.org/wiki/Thermal_printing https://en.wikipedia.org/wiki/Thermal_printing
warent 5y ago
I bought mine! Excited to try it out. I think I'm going to hook it up to a scheduler and have it print a to-do list for me every morning
alksjdalkj 5y ago
For those who bought one, is this the correct product page? I couldn't find any links on the github - https://www.aliexpress.com/i/1005002722811359.html https://www.aliexpress.com/i/1005002722811359.html
- kingcharles 5y ago
  There's a ton of them. I went for this one: https://www.aliexpress.com/item/1005003341930695.html https://www.aliexpress.com/item/1005003341930695.html
jwithington 5y ago
Can it print GitHub issues though?
- priansh 5y ago
  The HN collab I never knew I needed, although I doubt the whole issue could fit on there. Maybe the repo name, issue name and issue number instead?
shampto3 5y ago
This reminds me of the printer cat character from left-handed toons. http://www.lefthandedtoons.com/series/printercat http://www.lefthandedtoons.com/series/printercat
stevewillows 5y ago
I've been trying to find a good, portable impact printer for ages that has relatively easy to source paper. In a dream-scenario, I'd be able to cut A4 or 8.5x11 in half vertically and use that (or any other size) with some sort of rubberized feeder.
dcx 5y ago
This is insanely cute! But please strongly consider not buying one. Especially if you have kids, or are planing to have kids. This printer uses thermal paper, which uses BPA or BPS to develop the print, which rubs off easily [1]. BPA and BPS are absorbed into the body through the skin [2]. The amount used is 250-1000x the amount found in plastic bottles [3]. BPA and BPS are endocrine disruptors, and prolonged exposure to even low levels can result in severe endocrine and reproductive health issues (including birth defects); high levels are associated with a huge range of health issues [4]. Lobbying has clouded this issue in public perception [5]. But it's telling that supermarket cashiers have elevated levels of BPA in their systems, and the associated markers of health damage [6]. [1] https://www.webmd.com/cancer/news/20101207/bpa-can-rub-off-from-receipts-and-money-study-finds https://www.webmd.com/cancer/news/20101207/bpa-can-rub-off-f... [2] https://www.plasticpollutioncoalition.org/blog/2016/12/23/is-bpa-on-thermal-paper-a-health-hazard https://www.plasticpollutioncoalition.org/blog/2016/12/23/is... [3] https://www.pca.state.mn.us/green-chemistry/bpa-thermal-paper https://www.pca.state.mn.us/green-chemistry/bpa-thermal-pape... [4] https://www.medicalnewstoday.com/articles/221205 https://www.medicalnewstoday.com/articles/221205 [5] https://www.paperrolls.com.au/why-is-phenol-free-thermal-paper-so-important https://www.paperrolls.com.au/why-is-phenol-free-thermal-pap... [6] https://pubmed.ncbi.nlm.nih.gov/27729163/ https://pubmed.ncbi.nlm.nih.gov/27729163/
- andreareina 5y ago
  They make phenol-free thermal paper.
  - dcx 5y ago
    Interesting - that looks like it could be safe, though I don’t know enough to be certain (we all know how “BPA free” turned out). But either way it’s absolutely not the default when you buy online, which it looks like people in this post are doing, hence my comment.
    - l8rlump 5y ago
      I don’t see much reference to “BPA free” anymore. Why is that?

301 points by newman314 5y ago

Open printers of any kind are very welcome. I dream on an OSHW laser printer, engineered to be cheap, durable and easy to repair, with none of the bullshit manufacturers have been pushing on people for decades.

spoonjim 5y ago
I don’t know about repair but the $99 Brother laser printer doesn’t require any malware. You can print wirelessly from Windows/Mac/iOS without installing anything
- lelandfe 5y ago
  If you keep an eye out, you can snag one for much cheaper on eBay! The one I used back in college was great, and I picked it up for around $40.
- dylan604 5y ago
  I recently became much less enamored with my $99 Brother. There are certain paper types that it has issues pulling from the paper tray, but it can use it from the manual feed. However, the manual feed will not pull it straight and everything comes out at an angle.
  - tln 5y ago
    Interesting... what are you printing? I've had my brother laser for just about 10 years now, it's been awesome, regular paper, 80# cardstock and shipping labels being no problem from tray or feed. Envelopes haven't been great.
    - dylan604 5y ago
      Labels of various types that have specific places to print on the page is the issue for me. There's a test page that can be printed that shows alignment. The docs say to try something if it comes out skewed, but if that doesn't work then to take it to a certified place blah blah. It's clearly out of warranty, so that's a no go. I recently upgraded capabilities as doing more than could honestly be expected of a $99 printer. It has been well worth the expense of a higher model printer. Outside of that, I still love my $99 Brother B&W laser with scanner for anything not specialty labels. I look at it like not getting upset that a 1980s Yugo doesn't get nearly the same lap times as a 2000s model supercar
  - PaulHoule 5y ago
    If you get a cheap printer you have to buy expensive paper. I have the worst time printing in my house because the relative humidity level is very high in the summer. In the summer when my hair is curling and curling and curling from the humidity I have prints curling and trying to come off the walls. (In the winter I complain that static electricity is making my hair stand up on end.) You can't save money by buying 20 reams of paper on discount from Staples because the paper will soak up water and misbehave when you try to use it.
    - skybrian 5y ago
      Maybe a large plastic container and a desiccant would help?
- newman314 5y ago
  Fun fact: did you know that you can netcat firmware to a Brother printer? It's both cool and terrifying.
  - denysvitali 5y ago
    Well, you can literally print a firmware on some printers, and it will install it. Not sure what's worse
  - vhold 5y ago
    See also: https://github.com/nmap/nmap/issues/2237 https://github.com/nmap/nmap/issues/2237
  - pabs3 5y ago
    Surely it would verify signatures before installing the firmware?
    - newman314 5y ago
      You would think so but no.
- TheSpiceIsLife 5y ago
  $99 Australian dollars for second hand brother MFC-9330CDW colour wifi laser printer / scanner, needed new drums ($100 for the set of four) and one toner cartridge ($15), others are low but ok. Retails new for AU$550. $30 second hand monochrome laser printer at work I put by my workbench in a metal fabrication workshop, outside is filthy now, have run about 3000 pages through it, so about three toner cartridges, and a new. No issues. The software seems to be fine, light enough, unobtrusive.
tombert 5y ago
I find that giant office printers have given me a lot fewer headaches than "consumer" printers. I have a fifteen year old HP that I bought used on Craigslist for like $100, and it just magically worked upon plugging it into my router. I just use the generic Postscript driver on Macos. I don't think that driver is open source, but I suspect that you could fairly easily get a generic Postscript printer working with CUPS.
- rhplus 5y ago
  Did it come with a hard-drive filled with copies of every corporate document it had ever printed?
  - tombert 5y ago
    You know, I don't know...it might? I never opened it up enough to look for a hard drive.
  - kingcharles 5y ago
    LOL. The amount of shit I've bought off eBay and Craigslist that hasn't been wiped is significant. And that's without being totally bogus and actually putting any effort into data recovery which would surely work on most devices. Phones were crazy. So. Much. Homemade. Porn.
    - gumby 5y ago
      > Phones were crazy. So. Much. Homemade. Porn. Any of it good?
      - vangelis 5y ago
        Hopefully they did the right thing and factory reset it.
        kingcharles 5y ago
        Yes. I needed the phones clean. I had to buy up large numbers of random different handsets for testing SMS gateways.
pabs3 5y ago
Are there any printers with open source firmware at least?

tombert 5y ago

I wonder, if I wanted to recreate the Gameboy Camera with an emulator...has anyone done this with a webcam and a thermal printer? How hard was it?

RL_Quine 5y ago
Yes, emulators support the gameboy printer. In hardware it is implemented very close to the way the screen is written.
- tombert 5y ago
  That might be fun then; have the emulator write to a thermal printer, relive a bit of nostalgia I have for the awful printouts of Pokemon characters I used to have (and might still have in a box somewhere actually).
  - _def 5y ago
    Next step: make a DIY gameboy printer that works with a real gameboy
iamjackg 5y ago
Most emulators are able to export a PNG that you could then print with something like this project! They don't support using a webcam with the ROM for the Game Boy Camera though. If you buy the real thing, there are lots of projects for extracting and printing the pictures though. This project implements a fake GB Printer that you can then access via WiFi to download the prints: https://github.com/zenaro147/NeoGB-Printer https://github.com/zenaro147/NeoGB-Printer This project I wrote a while ago allows you to use a printer very similar to the one in this submission as an actual Game Boy Printer, connected to an original Game Boy: https://github.com/iamjackg/esp32-phomemo-gameboy-printer https://github.com/iamjackg/esp32-phomemo-gameboy-printer

bitwize 5y ago

The perfect accessory to go with your bear computer: https://i.gzn.jp/img/2009/07/13/rilakkuma/rp_001.jpg https://i.gzn.jp/img/2009/07/13/rilakkuma/rp_001.jpg

gardaani 5y ago
The design is as cute as Nabaztag / Karotz: https://en.wikipedia.org/wiki/Nabaztag https://en.wikipedia.org/wiki/Nabaztag
- boomboomsubban 5y ago
  The design is Rilakkuma, and seems to predate Nabaztag. https://en.wikipedia.org/wiki/Rilakkuma https://en.wikipedia.org/wiki/Rilakkuma
  - kingcharles 5y ago
    You're right: https://www.cnet.com/tech/computing/rilakkuma-netbook-the-best-computers-have-bears-on-them/ https://www.cnet.com/tech/computing/rilakkuma-netbook-the-be...
ta8903 5y ago
bear computer

jan_Inkepa 5y ago

I bought one of these because it was advertised as usb, but it being Bluetooth-with-special-(mobile-only!)app-only meant that I returned it. Nice to see someone jailbroke it :)

conroydave 5y ago

great now make it print github issues

afandian 5y ago
https://news.ycombinator.com/item?id=30803589 https://news.ycombinator.com/item?id=30803589

RBerenguel 5y ago

There’s also PPA6 for PeriPage thermal printers, a Python library using reverse engineering of the Bluetooth messages intercepted to the device: https://github.com/eliasweingaertner/peripage-A6-bluetooth https://github.com/eliasweingaertner/peripage-A6-bluetooth

ComputerCat 5y ago

This is absolutely adorable!

WoodenChair 5y ago

How would one go about reverse-engineering Bluetooth LE? Is it looking at packets through WireShark?

ctoth 5y ago
Using something like this[0]. [0]: https://greatscottgadgets.com/ubertoothone/ https://greatscottgadgets.com/ubertoothone/
tyingq 5y ago
Cheap device that can sniff BLE and send it to Wireshark: https://www.adafruit.com/product/2267 https://www.adafruit.com/product/2267 ($20) Overview on using it as a sniffer: https://learn.adafruit.com/introducing-adafruit-ble-bluetooth-low-energy-friend/ble-sniffer https://learn.adafruit.com/introducing-adafruit-ble-bluetoot... Still a lot of work though, if it's anything like LED signs I've reverse engineered. Trying to figure out if it's length encoded payloads or delimited payloads, what obscure checksums it might use, weird encoding of images, etc. And experimenting often hangs the device, or changes it's behavior significantly.
tunaoftheland 5y ago
Not reverse engineering, but I'd used free iOS/macOS apps that could inspect the traffic content. I also had access to the spec sheet from the manufacturer ("smart" BLE scale) that had where in the long payload digits were the weight, body fat, and water content, etc. Kinda fun and frustrating at the same time. If you truly wanted to punish yourself, you'd be doing this while trying to write a React Native app that communicated with the scale over BLE. :)
anfractuosity 5y ago
If there is an android app for the device, you can easily log the BLE data and load into wireshark https://www.mybluetoothreviews.com/what-is-bluetooth-hci-snoop-log/ https://www.mybluetoothreviews.com/what-is-bluetooth-hci-sno... shows how to capture the packets (you just go to the developer settings to turn it on)

rosstex 5y ago

Well that's the fastest I've purchased anything in a while.

sho_hn 5y ago

I just bought a Phomemo D30 thermal label printer to label my electronics component boxes last week, and I was wondering if I can hack things to send it images from my PC instead of the phone app it comes with. I found this repo, but I don't know if that's compatible with the D30 (the chassis pictured is of a different printer): https://github.com/vivier/phomemo-tools https://github.com/vivier/phomemo-tools Someone in Issues asked the same question, but the author wasn't able to answer for lack of hardware. I guess I need to try and/or contribute! The "Print master" phone app is uploaded under a different brand name (QUIN LLC), and other brands also seem to sell a D30 printer. I didn't really do the work of finding out where these truly come from. Perhaps someone's got a repo up under a different name. I've done 0 comparisons to other models in practice, but FWIW it does what I wanted it to do very well. All my stuff is obsessively well-labeled now. In fact, I labeled the printer in a mad-with-power move ... https://eikehein.com/stuff/label_printer.png https://eikehein.com/stuff/label_printer.png

zwass 5y ago
I actually just picked up the exact same printer but hadn't yet had time to see what OSS libraries were available yet. I had a previous project where I printed photos on a low res thermal printer. The images sucked, but people loved it.

vageli 5y ago

I would love to learn more about the reverse engineering process for a bluetooth device like this. It's too bad there is no link to a blog or additional documentation in the repo.

szundi 5y ago
You can buy a Nordic Semi usb devkit and their software can sniff. Maybe you can have the Android sw run in a virtual device and catch api calls
Karliss 5y ago
The repo states that they reverse engineered the Android app. So potentially 0% BLE specific reverse engineering and 100% of android Java. In some cases reverse engineering java code, which decompiles relatively well, can be easier than trying to sniff bluetooth packets, potentially dealing with standard bluetooth encryption and guessing what the raw bytes do.
- packetlost 5y ago
  Can confirm, reverse engineering Android apps is decently easy if you aren't afraid of manually parsing Java bytecode (it's not that bad). I tried to reverse engineer the encryption/decryption mechanism for a digital book app (it was garbage, and I just wanted to read my books in a nice app :( ) and was almost successful.
bilkow 5y ago
You can decompile android apps, which will give mostly the original Java Classes / functions with anonymized names (class A, function b, etc...). Framework classes and methods usually stay pretty much the same. See for example https://github.com/robertohuertasm/apk-decompiler https://github.com/robertohuertasm/apk-decompiler and https://github.com/vaibhavpandeyvpz/apkstudio https://github.com/vaibhavpandeyvpz/apkstudio (only used the first one but the seconds looks practical)

ursaspark 5y ago

looks like this is a variant of the other "portable mini thermal printers" available on aliexpresss https://www.aliexpress.com/item/1005002247175933.html https://www.aliexpress.com/item/1005002247175933.html possible these are compatible or at least similar enough, many similar products re-use modules and microcontrollers.

Karliss 5y ago
Did anyone else notice that title of word document in the second product image is "From spyware with love"?
- wolfgang42 5y ago
  Searching “Cow Tipping Championship in Vegas” eventually led me to this page: https://web.archive.org/web/20061117144904/http://www.spywarebiz.com/spylove.htm https://web.archive.org/web/20061117144904/http://www.spywar... Though how a 2005 blog post from a website selling antivirus software ended up being used as mock copy in a product photo is still a mystery to me...

ellisd 5y ago

I'd love to print to a Cat Printer from an iOS device via AirPrint. I see a ton of AirPlay to CUPS projects on Github, but I'm not quite sure how CUPS would be configured to simply call the Cat Printer python script. Any pointers on how to leverage CUPS or should I simply focus on an AirPrint server that directly calls Cat Printer?

bo0tzz 5y ago
I would take a look at https://en.opensuse.org/SDB:Using_Your_Own_Backends_to_Print_with_CUPS https://en.opensuse.org/SDB:Using_Your_Own_Backends_to_Print.... Going off a quick glance at the code examples, I think it might be fairly straightforward to hook into CUPS. https://github.com/jsmeix/cups-backends https://github.com/jsmeix/cups-backends also has some useful looking tools.
kayodelycaon 5y ago
It’s pretty easy to add backends to CUPS. They are just shell scripts. I’ve written a few ruby ones. Here’s an example of one I adapted for my own purposes: https://ofosos.org/2018/10/22/printing-to-remarkable-cloud-from-cups/ https://ofosos.org/2018/10/22/printing-to-remarkable-cloud-f...

pnemonic 5y ago

Lol'd at "Mean Threshold:" and then Grumpy Cat.

OJFord 5y ago

This is quite a tangent on label printing in general, but what I really want is a computerised label printer that does mechanical punched labels, like the classic Dymos and knock-offs. I still have and use one, basically because I don't use it enough that I need an electronic one, it'd just be handy, but I can't quite shake the appeal of the ~85% fully formed raised lettering.

ilaksh 5y ago

Does anyone know how the printhead elements are able to heat and cool rapidly enough? Is it just a very thin amount of a particular alloy and a precise amount and duration of voltage? Especially the cooling off part seems like it would require a really specific material. Unless all of the heat is someone removed as the paper scrolls.

kingcharles 5y ago
https://en.wikipedia.org/wiki/Thermal_printing https://en.wikipedia.org/wiki/Thermal_printing

warent 5y ago

I bought mine! Excited to try it out. I think I'm going to hook it up to a scheduler and have it print a to-do list for me every morning

alksjdalkj 5y ago

For those who bought one, is this the correct product page? I couldn't find any links on the github - https://www.aliexpress.com/i/1005002722811359.html https://www.aliexpress.com/i/1005002722811359.html

kingcharles 5y ago
There's a ton of them. I went for this one: https://www.aliexpress.com/item/1005003341930695.html https://www.aliexpress.com/item/1005003341930695.html

jwithington 5y ago

Can it print GitHub issues though?

priansh 5y ago
The HN collab I never knew I needed, although I doubt the whole issue could fit on there. Maybe the repo name, issue name and issue number instead?

shampto3 5y ago

This reminds me of the printer cat character from left-handed toons. http://www.lefthandedtoons.com/series/printercat http://www.lefthandedtoons.com/series/printercat

stevewillows 5y ago

I've been trying to find a good, portable impact printer for ages that has relatively easy to source paper. In a dream-scenario, I'd be able to cut A4 or 8.5x11 in half vertically and use that (or any other size) with some sort of rubberized feeder.

dcx 5y ago

This is insanely cute! But please strongly consider not buying one. Especially if you have kids, or are planing to have kids. This printer uses thermal paper, which uses BPA or BPS to develop the print, which rubs off easily [1]. BPA and BPS are absorbed into the body through the skin [2]. The amount used is 250-1000x the amount found in plastic bottles [3]. BPA and BPS are endocrine disruptors, and prolonged exposure to even low levels can result in severe endocrine and reproductive health issues (including birth defects); high levels are associated with a huge range of health issues [4]. Lobbying has clouded this issue in public perception [5]. But it's telling that supermarket cashiers have elevated levels of BPA in their systems, and the associated markers of health damage [6]. [1] https://www.webmd.com/cancer/news/20101207/bpa-can-rub-off-from-receipts-and-money-study-finds https://www.webmd.com/cancer/news/20101207/bpa-can-rub-off-f... [2] https://www.plasticpollutioncoalition.org/blog/2016/12/23/is-bpa-on-thermal-paper-a-health-hazard https://www.plasticpollutioncoalition.org/blog/2016/12/23/is... [3] https://www.pca.state.mn.us/green-chemistry/bpa-thermal-paper https://www.pca.state.mn.us/green-chemistry/bpa-thermal-pape... [4] https://www.medicalnewstoday.com/articles/221205 https://www.medicalnewstoday.com/articles/221205 [5] https://www.paperrolls.com.au/why-is-phenol-free-thermal-paper-so-important https://www.paperrolls.com.au/why-is-phenol-free-thermal-pap... [6] https://pubmed.ncbi.nlm.nih.gov/27729163/ https://pubmed.ncbi.nlm.nih.gov/27729163/

andreareina 5y ago
They make phenol-free thermal paper.
- dcx 5y ago
  Interesting - that looks like it could be safe, though I don’t know enough to be certain (we all know how “BPA free” turned out). But either way it’s absolutely not the default when you buy online, which it looks like people in this post are doing, hence my comment.
  - l8rlump 5y ago
    I don’t see much reference to “BPA free” anymore. Why is that?