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• How to mount a phone?

  Chron-O-John • 03/21/2026 at 14:41 • 0 comments

  sudo mount /dev/phone0 ~/belt

  So, yesterday I completed the binning process:

  • 9 Phones with 90% battery health or better
  • 17 between 80% and 89%
  • 7 between 70% and 79%
  • 1 under 70%
  • 6 (partially) non-functioning
  • 4 device-locked

  One phone that was initially locked (“iPhone unavailable”) I managed to become usable again by re-flashing in DFU-Mode. Unfortunately the device-locked phones are all comparatively new ones. Maybe I will be able to restore them when considering notes at work.

  So only using the 90+ and 80+ phones I will be able to complete the vest – I thought.

  Turns out – as suspected – the battery health indicator isn’t the best. I fully charged the 90+  and left them turned on (but not charging) overnight. One of the phones was under 30% next day, two at about 75, the rest within reasonable range. At least two of the phones have 3^rd party batteries, so I hope it’s only a calibration issue. But I doubt it to be honest. So I will have to use some of the 70+ phones or manage to unlock some. I am pretty confident I can unlock at least one, because the person who’s used it in the past is still working for the company.

  The mount

  So while the next 10 phones get their charge (I haven’t bought all 24 cables yet, because I want to make sure that they are suitable first) I designed the first iteration of a “phone-tile”

  I want to keep the bottom part universally usable for every model (except for the large ones like iPhone 8 plus). So I took measurement of the widest, tallest and thickest models and constructed a bottom-case. The phone will be placed in the upper compartment using an adapter plate-insert to compensate for the differences in dimensions. The bottom compartment is for the charging plug and some cable to keep it neat and tidy. The slots in the upper compartment (underneath the phone) are for either horizontally or vertically mounting the whole thing on a strap. Finally, I will construct an upper-plate that will slide in from the top to cover everything except the screen.

  I can already see, what needs to be changed for the second design iteration: the slot at the bottom is most likely to narrow for the charging plug (which is a bit thicker than the cable), so I have to adjust for that.

  Available time

  I vastly overestimated the amount of time I can use for the project. I’m meeting a few friends tomorrow evening and will be visiting a concert (Feuerschwanz) on Thursday. So that will leave only a few hours tomorrow, 3 evenings and maybe a few hours before the concert to work on the project. Friday is my usual day-off from work, so, I guess, I will have to do more than just last-minute fixes on Friday. Anyway, good news from the software-side:

  Speech recognition

  Well, I thought I have a Raspberry 5, turns out its only a raspberry 4 that’s been powering one of my 3D-Printers. Luckily, it’s the 4GB version. So, I’ve looked up faster-whisper on the raspberry, and it should – theoretically - work. While using about 1.5 the amount of energy a raspberry 5 would. That could be an issue. I will measure the power consumption and calculate the amount of energy/batteries needed. I salvaged a lot of 18650 cells, so I could build something out of them. But I don’t think I have enough time for that, so I will resort to powerbanks, if possible. I’ll also try to undervolt the raspberry and limit clockrate to keep the peak power consumption low, hopefully under 2 amps so an average powerbank could be used.

  On the bright side whisper speech recognition already transcribes numbers as a row of digits as opposed to written-out words. So a script only has to look for a whitespace followed by any amount of digits, followed by a whitespace (yeeey regular expressions…) to recognize a number and trigger a display-update.

• Got the stash

  Chron-O-John • 03/20/2026 at 19:24 • 0 comments

  Ok, so I went to the office and got the phones. Quite an impressive amount, actually. I also found some Android and Microsoft OS phones, but didn't take them with me as they were all mixed makes and models. I also left two old iPads behind, as they are not needed for the current project, but might be a nice addition later on.

  Right now I am in the process of binning (quite literally, actually) the phones by battery health percentage. I don't know how accurate it is, but that's the easiest one as a first indicator.

  Most of the phones haven't even been reset, but luckily enough nearly all of them still have the default-lock code that has been configured, when the devices were handed out years ago. Right now I am at about 50% of the binning process with 3 device-locked phones I am unable to unlock for the time being, and even one phone with 100% battery health. This phone has been on the charger most of the time, so no wonder it's still perfect.

  I am quite confident, that I will get 24 iPhones with at least 80% battery health; models as old as iPhone 4 (2010) all the way up to iPhone 8 and XS (2018).

  One of the phones that didn't have the default lock-code had a note stuck to it with the correct one written on it - which was quite nice.

  oh, and you can pull out a lot of dust cleaning these old charging-ports

• Initial thoughts and considerations

  Chron-O-John • 03/20/2026 at 14:36 • 0 comments

  The party, where I want to wear the vest, takes place in 8 days. That’s a very – ahm – condensed timeframe to advance the project from an idea into a working state.

  I wouldn’t necessarily consider this a problem. I need a clear deadline and some sort of pressure to do stuff and work best. So that’s a given.

  I also need a good plan and milestones, so I don’t get lost in unimportant details and I need to cut corners wherever possible (not that iPhones have that many corners to begin with, most of them are rounded) to progress as fast as possible. I don’t need perfect solutions for the first working vest – I need working ones.

  ---

  So, what's the bare minimum?

  • 4 Phones in portrait mode side-by-side on the front and the back of the vest. Each displaying a random number for some time
  • 8 Phones on either side, maybe 4 more (two left and right) on/as straps leading to the shoulders.
  • That would be 12 phones on the front and back, so 24 in total. Do I have that many phones? I am pretty sure (yet I still must get them from the office as I am on holiday right now)
  • Would that all be the same phone model as initially planned? Not quite sure, maybe not.
  • Does that matter? – not really. I plan to 3d-Print mounting for each phone, so as long as the screens are roughly the same size it should be fine.
  • I will use a web browser and some JavaScript to display the digit. Stored locally, so no internet/Wi-Fi connection is required.

  Ok, the 4-phone on either side version sounds more like a fallback solution that can be achieved using some glue, tape and a safety vest. Good to have that.

  What do I really want to have?

  Do I have bigger plans and ideas that would require a network or even internet connection? Definitely! But let's not go overboard with ideas and settle for a minimum first.

  Nevertheless, I will write down additional cool stuff I have in mind:

  • Have the digits scroll through the phones
  • Implement some sort of voice recognition, so that every time a phone picks up someone saying a number, all the phones are displaying it - that would be really awesome, but will most likely require an internet connection to offload voice recognition. It would definitely require the devices to be interconnected via Wi-Fi. Not that much of a problem
  • Send the video of a front-facing phone’s camera to the opposing one on the backside and vice versa to sort of create the illusion of a “hole” in my body
  • Display audio activated Winamp-Style visualizations. Would be cool for further use on concerts and festivals, but not all that useful at the party – I plan to stick with the numbers theme

  Creating the possibility that the phones are somehow synchronized (I think of WebSockets) will allow me to quickly integrate new devices. The party will start outdoors, but it will transition the birthday person’s home later on. Other guests could then simply open a website and place their phone somewhere around the apartment, so when the (planned) number recognition kicks in the corresponding number is literally (or should I say digitally) displayed everywhere.

  I am kind of having an epiphany right not. I simply want to write a wordplay on digits vs letters and realized, why its called digital. Digits! As opposed to literals – letters. Mind blown. But back to the topic.

  Challenges

  Thinking about the project, what would be the biggest challenges to overcome?

  Battery runtime

  Even with the minimal glue-and-tape version battery runtime could be an issue. The party starts at 14:00 (so 2 pm freedom-time) and will likely go on until 5 in the morning or so next day. That being an ambituous plan itself (even without the phones), considering that the screens need to be at maximum brightness while being outside, I doubt that the phones will last with one charge of their already aged batteries. So I need an easy and quick way to recharge them all at once or even have them connected to a power bank all the time. Considering...

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