Show HN: ESP32 RC Cars • Hacker News Board

Re: Show HN: ESP32 RC Cars

#41

Post by bri3d » Sun, Feb 02, 2025, 8:28 PM UTC

IshKebab wrote: post #40

emidoots wrote: post #22

Earlier quoted context omitted.

FPV today is largely using ExpressLRS[0], an open protocol for running FPV quads' control links (also using esp32 usually) Video for FPV quads on the other hand is divided: some use analog (mostly because when you lose signal, it's a gradual loss rather than complete loss + a reconnection process), while others use 802.11-based communication which is actually quite competitive. Walksnail Goggles for example use 802.1…

I think graceless degradation isn't an inherent property of digital radio. You definitely could have some kind of digital modulation that takes advantage of FEC etc. but gracefully degrades. I'm sure it exists, there probably just not much market for it.

Almost all existing digital FPV systems gracefully degrade as much as they possibly can, both by using FEC and walking down a large number of available MCS as link quality gets worse (and reducing bitrate to match). But when they do eventually fail, re-sync is a much harder problem for them than it is for analog.

Re: Show HN: ESP32 RC Cars

#42

Post by aleksiy123 » Sun, Feb 02, 2025, 8:31 PM UTC

Pretty awesome. I was thinking about trying to create some kind of automatic toy for my cat that would avoid obstacles. Maybe this could be the base instead of the one I picked up https://www.aliexpress.com/item/1005007634018076.html

Re: Show HN: ESP32 RC Cars

#43

Post by t0mek » Sun, Feb 02, 2025, 8:42 PM UTC

12 years ago, when we already had Arduino but no ESP32 yet, I built this thing:

https://newton-net-pl.translate.goog/2012/01/robot/?_x_tr_sl...

It was made of an old HTC Magic phone, acting as camera+wifi transmitter, connected to Arduino via its serial port and level shifter, to control the servo and a RGB LED. I had a lot of fan with that, even if the connection wasn't really to stable.

Thanks for sharing, maybe it's time to revive the project with the next generation of the microcontroller.

Re: Show HN: ESP32 RC Cars

#44

Post by IshKebab » Sun, Feb 02, 2025, 9:08 PM UTC

bri3d wrote: post #41

IshKebab wrote: post #40

Earlier quoted context omitted.

I think graceless degradation isn't an inherent property of digital radio. You definitely could have some kind of digital modulation that takes advantage of FEC etc. but gracefully degrades. I'm sure it exists, there probably just not much market for it.

Almost all existing digital FPV systems gracefully degrade as much as they possibly can, both by using FEC and walking down a large number of available MCS as link quality gets worse (and reducing bitrate to match). But when they do eventually fail, re-sync is a much harder problem for them than it is for analog.

Right, but I don't see any reason why that must be the case. It's not a fundamental limitation.

Re: Show HN: ESP32 RC Cars

#45

Post by amenghra » Sun, Feb 02, 2025, 10:09 PM UTC

This is a fun read if you want to automate the RC car. It's from a couple years ago, there might be easier/better way to achieve similar results today: https://hackaday.com/2021/10/25/fast-indoor-robot-watches-ce...

Re: Show HN: ESP32 RC Cars

#46

Post by lostmsu » Sun, Feb 02, 2025, 10:30 PM UTC

Does anyone know if there is a car kit where you could just install an Android smartphone and have it be the camera + brain?

Re: Show HN: ESP32 RC Cars

#47

Post by GardenLetter27 » Sun, Feb 02, 2025, 11:22 PM UTC

I did something similar with Rust and the Steam Deck not long ago - https://github.com/jamesmcm/esp32_wifi_tank

Re: Show HN: ESP32 RC Cars

#48

Post by bri3d » Mon, Feb 03, 2025, 12:02 AM UTC

IshKebab wrote: post #44

bri3d wrote: post #41

Earlier quoted context omitted.

Almost all existing digital FPV systems gracefully degrade as much as they possibly can, both by using FEC and walking down a large number of available MCS as link quality gets worse (and reducing bitrate to match). But when they do eventually fail, re-sync is a much harder problem for them than it is for analog.

Right, but I don't see any reason why that must be the case. It's not a fundamental limitation.

To a great extent you trade statefulness (inter-frame compression, FEC, HARQ, sounding parameters, overhead) for efficiency, so improving link recoverability comes at a cost. There is an existing solution which makes this trade - HDZero. It works amazingly at close range in clean RF environments and has good analog-esque falloff characteristics, but in terms of absolute efficiency it is very bad and therefore does not have the same quality or range as other solutions. Certainly a better hybrid approach is possible but to your point, niche.

Re: Show HN: ESP32 RC Cars

#49

Post by hk1337 » Mon, Feb 03, 2025, 1:45 AM UTC

This is really cool.

It could be like Goldeneye, slappers only.

Just find a better way to slap than bumper cars.

Re: Show HN: ESP32 RC Cars

#50

Post by conductr » Mon, Feb 03, 2025, 2:51 AM UTC

mattsroufe wrote: post #32

Scene_Cast2 wrote: post #20

The big issue with FPV, and the reason it stayed on analog tech for so long is because of latency. How is the latency for this project?

Hi, thanks for checking out the project. I don't really have anything to gauge by like experience with FPV drones but latency hasn't been an issue on my wireless network even with all the other household devices connected. I think the frame rate is mostly limited by how quickly the esp32 can capture images. In my python script I measure FPS and was receiving about 50 fps from the esp32s. I recently bought a travel ro…

My guess is latency won’t be an issue for you’re using it over LAN and the device is traveling lower speeds. If you wanted the controller inputs to travel over the internet to your router and/or going high speed where reaction time and maneuvering were more of a concern then latency would become an issue