Tech Explained: What Survives an Internet Shutdown?

The protest in Jantar Mantar, Delhi, ended after Education Minister resigned. But internet shutdowns during the protest, followed by a Govt direction asking GitHub to remove opensource BitChat, concern me as a technologist. Privacy is a fundamental right in India, and personal communication cannot be held hostage to the whims of Govts. Alternate decentralized routes exist, I want to talk about that today.

When mobile data is blocked, your phone still has Bluetooth and Wi-Fi. BitChat uses Bluetooth Low Energy to discover nearby phones. Each phone relays packets, so a message can cross several people without towers or a central server. It works best in a dense crowd. Encrypted messages can be stored temporarily on nearby phones and delivered when one later encounters the recipient.

A local Wi-Fi network is another option for a confined site. A RPi Zero 2W can act as both an access point and a local chat server. Even a normal home router can provide the network while phone apps exchange messages directly between connected devices. Several battery-powered portable nodes can widen coverage, but they need a Wi-Fi mesh backhaul that synchronizes messages between them.

For longer range, an engineering option is Meshtastic. Your phone connects over Bluetooth to a LoRa radio, while those radios relay short packets across a wider area. It works well for text, location and coordination. However, every person in the network needs extra hardware, making it harder to deploy spontaneously, and LoRa has too little bandwidth for images or video.

These systems provide local messaging, not internet access. They reach the wider internet only when one node has an external connection. A jammer aimed only at cellular bands would leave Bluetooth, Wi-Fi or LoRa working unless its super wideband(highly unlikely).

Any tool/tech can be misused. That is true of phones, cash and encryption too. That does not justify banning it. When the Govt blocks private communication because it cannot monitor every message, it is actively pursuing surveillance power. The protest may be over, but the precedent remains. Hope this doesn’t repeat again.

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Tech Explained: Lithium AA cells

I was looking for a long-term rechargeable option for a few household gadgets. I knew 1.5 V lithium AA cells existed, but I had never used them till now. So I thought today was a good day to explain how they work.

Lithium batteries in consideration are of two kinds. The first is primary lithium AA, using lithium–iron disulfide, or Li/FeS₂. It is non-rechargeable and naturally delivers an alkaline-compatible 1.5V. These cells are light, handle high loads and cold weather well, rarely leak, and branded versions can have a shelf life of around 25 years. They are roughly ₹200-₹300 per cell in India, they suit outdoor sensors and “put-and-forget” devices.

The second kind fits a rechargeable lithium system inside an AA shell. It usually contains a 3.7V lithium-ion cell, a protection circuit, and a buck converter that steps the output down to a steady 1.5V. USB-C versions also contain their own charging circuit. The 5V input charges the internal cell, while the buck converter powers the gadget. So every battery is has a tiny charger, protection system, and regulated power supply.

They can do approx 1,000-1,200 recharge cycles. Real life as always depends on temperature, discharge depth, charging quality, and how long the cell stays fully charged. Four-cell packs in India cost around ₹1,200-₹2,000. A good thing about them is they always provide a steady 1.5V compared to alkaline ones that start at 1.5V and drop to around 1V when dead. Lithium versions are also lighter and often provide more usable energy.

There are trade-offs. The converter adds standby drain, switching noise, and a current limit. That makes these cells less suitable for wall clocks, low-power remotes, and sensitive audio equipment. In the end, the choice depends on the device and how you use it, rather than one chemistry being universally better. Please know that Lithium ones are a valid option for your future needs if you want to spend more.

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