Building a Real-Time HN Display for $15 • Hacker News Board

Re: Building a Real-Time HN Display for $15

#21

Post by mlhpdx » Mon, Jan 26, 2026, 3:24 PM UTC

rcarmo wrote: post #10

I love this because it uses UDP _and_ a CYD (Cheap Yellow Display, which is what we hardware nerds have taken to calling these). I have two or three of these around, one as a 3D printer remote, another as a pseudo logic analyzer, and a caseless one that I use as a Micro Python sandbox. I've been using UDP to send CPU stats for my machines for ages ( https://github.com/rcarmo/raspi-cluster/blob/master/tools/se... is a…

WireGuard doesn’t add noticeable battery drain in my experience. I have a fleet of Xiao ESP32-C3 devices with DS1820 temperature sensors that run on batteries and send samples over WireGuard.

The battery drain is 100% a function of the transmit time, so by pre-encrypting the buffers before powering on the radio I save a bit. Likewise for the response handshake - get the packet, shut down the radio, then decrypt it.

When sending samples between handshakes, I don’t have to wait for an ACK of any kind - I just send the packet and shut down the radio. That saves a ton of power compared to TCP.

Re: Building a Real-Time HN Display for $15

#22

Post by mlhpdx » Mon, Jan 26, 2026, 3:28 PM UTC

password4321 wrote: post #18

lormayna wrote: post #7

Why not using MQTT? A Lambda that fetch new comments from HN, parse them into Markdown and push into MQTT; the ESP only needs to subscribes a topic on MQTT and render the messages.

The snarky answer is that MQTT doesn't require the author's UDP to AWS Lambda gateway SaaS⁰. I did find MQTT flavors that support UDP but neither MQTT/UDP nor MQTT-SN seem concerned with WireGuard-level security. ⁰(This article is AI-assisted content marketing good enough that I didn't realize it until ¾ through.)

Fair point that yes I’m eating my own dog food here. And I’ve been called a robot enough times maybe I should keep track.

To the question, UDP is easier on a battery than MQTT.

Re: Building a Real-Time HN Display for $15

#23

Post by password4321 » Mon, Jan 26, 2026, 6:47 PM UTC

mlhpdx wrote: post #22

password4321 wrote: post #18

Earlier quoted context omitted.

The snarky answer is that MQTT doesn't require the author's UDP to AWS Lambda gateway SaaS⁰. I did find MQTT flavors that support UDP but neither MQTT/UDP nor MQTT-SN seem concerned with WireGuard-level security. ⁰(This article is AI-assisted content marketing good enough that I didn't realize it until ¾ through.)

Fair point that yes I’m eating my own dog food here. And I’ve been called a robot enough times maybe I should keep track. To the question, UDP is easier on a battery than MQTT.

To be clear I understand you are not a robot, but the article reads more as LLM generated especially toward the end which is why I said "AI-assisted".

Thanks for sharing this project; TIL about AliExpress Dollar Express tiny touch screen ESP32 dev kits for first-time buyers for $9 including shipping.

Re: Building a Real-Time HN Display for $15

#24

Post by Terretta » Tue, Jan 27, 2026, 4:01 AM UTC

Fantastic project, and imma save it for several ambient info things I'm looking to do.

But the LLM patterns and wording are tedious, especially:

No this. No that. No the other. Just much, sameness, repeated.

- And the bulleted question call and response? Too much of that too.