The Tech Blog

Small good news for wireless in India this week. The government has finally delicensed part of the 6 GHz band for Wi-Fi at home. I see a new rule came about this week to open up 5925-6425MHz for low power indoor and very low power outdoor devices on a licence free, shared basis. This means routers and clients that support 6 GHz can now legally use it in India alongwith 2.4 GHz and 5 GHz.

6GHz gives Wi-Fi 6E/7 a lot more clean spectrum than 5 GHz. We have 500MHz Bandwidth free because of the de-licensing. That is still big enough for three 160 MHz channels (3×160 = 480 MHz, plus guard) or one 320 MHz channel with some spectrum left. Wider channels means faster traffic. That lets a good router plus a 6GHz phone or laptop move traffic faster with less interference when both ends support it. Notification says low power indoor access points can radiate up to 30 dBm(1W) Radiated Power, while very low power outdoor devices are capped to 14 dBm. Emissions outside 5925-6425MHz must sit below −27dBm/MHz, so there cannot be any power leakage into neighbouring bands. Equipment also needs integrated antennas and Indian type approval, so no giant external 6GHz sticks.

All of this means if you have a home server and connected devices like NAS or TVs, you can now get superfast speeds. But Physics still applies here. Compared to 5GHz, you see approx 1-2 dB extra loss through a wall for 6GHz, which means about 10-20% less usable range. Meaning, ideally you might want to have direct Line of light or an access point in the same room for full speed benefits. If you have those high-end routers I would configure all the high bandwidth devices dedicated on this 6GHz channel and others on a separate longer range 2.4GHz channel.

Many recent phones, laptops and routers already ship with 6 GHz capable radios, but had the band disabled in India. Most likely you will see firmware updates from these vendors to enable the 6GHz bands in India, though some gear will probably never be updated. So be on the lookout.

It’s CES week, and as usual, I wanted to have a look at the wackiest tech products put out this week and figure out the tech behind it. This year that pick is iPolish, the press-on nails that change colour with a phone and a small wand. Search online for the product demo videos, it’s pretty good.

If you strip away the fancy stuff, it’s a form of e-paper screen. They call it a screen with “Electrophoretic nanopolymers”. Electrophoretic just means charged pigment particles move in a fluid when you apply an electric field. The pigment you pull to the top is the colour you see. Once set, it is stable and needs no refreshing or power to retain the colour. I have previously written about the ePapers and how it works in detail if you want to read more about it.

I looked into the patents filed. It describes a stack that feels like a tiny curved display. There is a nail blank, transparent electrode, microcapsule pigment layer, and a patterned backplane electrode with traces. It comes with a unit called as wand which is controlled via BLE from your phone app. You choose a shade, but it’s stored as a colour file that is basically a voltage list. For the movement of particles (for colour change) you can’t just give a DC voltage, You typically need a balanced pulse sequence in the ±15 V to ±20 V range to avoid ghosting and charge trapping. The wand pushes that waveform through metal contacts on the back of the nail. Contacts are like a programming header to configure and then retain the colour.

Pricing seems to be around $99 and after that around $3.5nail for replacement. The website talks about the nail being active only for 30 days. I’m not fully sure if that’s a real electrochemistry or materials lifetime limit OR it could be purely be the company chasing the subscription revenue model, which I would say is a downer.

Anyways interesting tech. The core idea is solid. If they can manufacture a curved, addressable e-paper laminate this cheaply, the obvious next step is larger form factors. Colour changing dresses probably…