| ▲ | opello 5 hours ago |
| > I'm assuming it's to prevent moisture from corroding a port of some kind. The primary value discussed in the talk was electrical isolation since there's mains voltage in the appliance and the potential for shorts or inadequate isolation would require some kind of isolation, so a path that optically isolates the communication makes quite a bit of sense. I'm also curious if other devices have gone this route. |
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| ▲ | bri3d 5 hours ago | parent | next [-] |
| LG appliances at least used to use acoustic signaling for diagnostics: hold a phone up and the washer makes some modem-esque (I think it’s 4-tone / 4-FSK) noises and the app or technician can diagnose issues. It was originally engineered to even work over voice codecs, so a customer without a smartphone could relay the diagnostic session to a technician. |
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| ▲ | opello 5 hours ago | parent | next [-] | | That's pretty cool. I found a write-up[1] on it but unfortunately didn't come across any examples of the communication. [1] https://github.com/kabelincho/LG-Smart-Diagnostics-modem | | |
| ▲ | bri3d 5 hours ago | parent [-] | | There are lots of examples on YouTube, this one seems succinct: https://youtube.com/shorts/3Eb315vL9uw . They picked good tones to make it satisfying IMO. I don’t know of anyone who’s reversed the bitstream in public, though, but it doesn’t seem like it should be very hard. | | |
| ▲ | opello 4 hours ago | parent [-] | | That's a great example, thanks! I was looking for "LG Smart Diagnostics" and "audio" and then "LG Acoustic Diagnostics" and found TVs calibrating their audio playback but not this. Trying "LG Audible Diagnosis" found a bunch like yours. |
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| ▲ | imglorp 5 hours ago | parent | prev | next [-] | | That's some advanced gatekeeping right there. Where other appliances might have a blink code or several digit error display (Miele) to look up in a manual, the phone method tires you to the manufacturer. | | |
| ▲ | noAnswer 3 hours ago | parent [-] | | The support hotline will ask you to hold your phone towards the device. It is less error-prone (than a human) and contains more info than a blink code. I find it really clever. | | |
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| ▲ | atoav 20 minutes ago | parent | prev | next [-] | | The absolutely "leetest" thing I have ever seen was a device where the firmware update was to be done by: 1. Hold a button while booting (pretty normal) 2. This reconfigures the circuit path of one of the LEDs so it is reverse-biased to VCC via its resistor and switches one of the microcontroller GPIOs to ADC input 3. You go to a website that plays a strobe pattern (encoding the firmware) 4. You hold that website in front of the LED till other LEDs blink, signifying a successful update They could have done this using a photodiode, but no, they had to abuse an LED. Not many people are aware that LEDs can in a certain configuration be used to measure light. | |
| ▲ | landr0id 4 hours ago | parent | prev [-] | | >so a customer without a smartphone could relay the diagnostic session to a technician Do you mean by mimicking the noises themselves? | | |
| ▲ | wpm 4 hours ago | parent | next [-] | | No you see you just need to buy specially marked boxes of Cap'n Crunch that have a plastic whistle in them that plays the tones for you. | | |
| ▲ | userbinator 2 hours ago | parent [-] | | I wonder how many HN readers still get that reference (and 2600, etc.) | | |
| ▲ | hunter2_ 24 minutes ago | parent [-] | | We make use of a service already existing without paying for what could be dirt-cheap if it wasn't run by profiteering gluttons... |
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| ▲ | notpushkin 3 hours ago | parent | prev [-] | | By holding their phone up to the machine. |
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| ▲ | eru 2 hours ago | parent | prev | next [-] |
| Alternatively, I guess you could also use really thin cables to carry the low voltage paths; and that act as fuses, if ever a lot of current at high voltage was flowing across them? But probably not very reliable both in regular operation and as fuses. We have a Miele washing machine and a Miele dryer. Solid machines all around even after years of use. |
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| ▲ | mjochim 4 hours ago | parent | prev | next [-] |
| Electric meters often blink a signal LED for every X kWh, so other devices can read the signal. I'm not sure if this is used for bidirectional communications, though. |
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| ▲ | netsharc 5 hours ago | parent | prev [-] |
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