fpx: easy USB‑C power for all your devices | Hacker News Reader

fpx: easy USB‑C power for all your devices

fpx.oxplot.com

49 pointsoxplot18 comments

Clever way to make it configurable, and a good way to differentiate it from the cheap aliexpress versions! And nice to see the development from your earlier versions.

> The board has a sensor which reads your desired configuration from the light pulses generated on this page and stores them on the onboard NVM

now _that_ is fricken cool... albeit open to sabotage, but still wow

I'm trying to think of what other products/projects I'm aware of using optical coupling for configuration - the Bloomberg B-Unit used/uses a similar screen-flash strategy for authentication, and some first-person drone cameras can leverage adding/removing the lenscap to navigate the menus, but this configuration mechanism isn't as popular as I'd expect it to be given how clever and straightforward it is. This is a really cool project!

I have a bunch that use audio coupling, but none that use optical coupling.

An example is this: https://www.ericasynths.lv/triggergen/

Not configuration, but some banks in Europe have or had devices to authorize online banking transactions using the principle: A standalone device you put your banking card in and hold it up to the screen, the banking site blinks the transaction information, you confirm the transaction on the device and it gives you TAN code to type in.

Electric Imp used screen pulses for configuration. It feels like magic everytime.

The later Psion (or Cannon?) PDAs used monitor-flashing as a way to send serial data to the PDA from PC -- this was used for quickly filling in address books and so-on.

When I used it then I thought 'Wow, this is neat -- but probably dangerous for epileptics.' . Much tidier than dealing with an RS232 interface or the like -- just use a photodiode.

edit: it was the Sharp Zaurus series that used the optical data transfer -- I think. it's been years and I used to be too into PDAs

edit 2 : Royal also had a PDA series with optical transfer; but i'm not sure whether or not Royal made their own hardware products.

edit 3 : I found the Royal organizer : 'Point your FL95 PC Organizer at your desktop PC monitor. Watch as flashing bars of light send information to the FL95 PC Organizer.'

They call it 'Timex Datalink' [0]

https://www.amazon.com/FL95-Organizer-RoyalGlo-Nitevue-displ...

[0]: https://en.wikipedia.org/wiki/Timex_Datalink#Optical_sensor

https://en.m.wikipedia.org/wiki/Timex_Datalink

I'm using in my current projects PD boards from Ebay, so I could be interested. Ebay boards are programmable using a single button on the board itself and are less expensive. This one is very cool but IMHO has two weak points: 1. "The board has a sensor which reads your desired configuration from the light pulses generated on this page and stores them on the onboard NVM". What if the company go out of market ? How can a customer reprogram his boards without website? 2. Is that secure ? What if a malicious actor reverse the website logic going around reprogramming the boards to provide max voltage ? It should have a safe button but, at that point, could be convenient to use directly that button to change configuration.

I'm very interested to know what board you're using at the moment. I did consider using a button, however given the small size I wanted the board to be, it was not possible to have anything mechanical on it.

1. The protocol is actually fairly simple and open. Everything including the website is open source. In fact the site is a single page HTML which can be saved and opened offline.

2. The point about sabotaging which others have mentioned, is a valid point and I have thought about using a sort of a password to restrict who can configure it. I haven't found a user-friendly solution to this yet. As this board is meant to be embedded inside of an enclosure, I am relying on physical obstruction of the sensor as a form of security.

I'm using ZY12PDN USB-C PD boards ( https://www.youtube.com/watch?v=aIHj3qMRqqE ) About point 2, IMHO, better a jumper to disable programming mode than having to obstruct the sensor.

Jumper is a good idea as it's something that can fit on the fpx board.

Darn, I wish this was available a few months ago. I just went through the effort of assmbling my own PD Buddy sinks because they are currently out of production.

Really cool and useful project!

To protect it a bit more against an easy sabotage you could add some symmetric key logic in the light emitter and receptor (certainly it already crossed your mind)

Thanks for the suggestion. I've just added a tip on the site about putting the board inside an opaque enclosure. That's what I had in mind as far as security goes. I have thought about giving each individual board a unique ID which will be verified when configuring the board.

It's still too expensive to just put into things, but still it's a great evolution of the buddy sink!

When will we get easy to use modules like this for power output?

> When will we get easy to use modules like this for power output?

What do you have in mind? Are you thinking of a USB-C to USB-C voltage converter?

I was originally looking for something allowing me to make a power supply for my USB-C only laptop to build a (large and cheap) power bank from some 18650 cells I had lying around.

I understand that communication with the voltage converter would likely be so complicated they should be integrated with each other, then integrating all the other battery management stuff wouldn't be so far either.

Admittedly it has been a few years ago, but the last time I looked nothing like this was available.

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