Ask Hackaday: Is The ESP8266 5V Tolerant?

The ESP8266 is the reigning WiFi wonderchip, quickly securing its reputation as the go-to platform for an entire ecosystem of wireless devices. There’s nothing that beats the ESP8266 on a capability vs. price comparison, and this tiny chip is even finding its way into commercial products. It’s also a fantastic device for the hardware tinkerer, leading to thousands of homebrew projects revolving around this tiny magical device.

In every technical document, summary, and description of the ESP8266, the ESP8266 is said to be a 3.3V part. While we’re well into the age of 3.3V logic, there are still an incredible number of boards and hardware that still operate using 5V logic. Over on the stack, [Radomir] is questioning this basic assumption. He’s wondering if the ESP8266 is 5V tolerant after all. If it is, great. We don’t need level converters, and interfacing the ESP to USB TTL serial adapters becomes much easier. Yes, you’ll still need to use a regulator if the rest of your project is running at 5V, but if the pins are 5V tolerant, interfacing the ESP8266 with a variety of hardware becomes very easy.

[Radomir]’s evidence for the possibility of 5V tolerant inputs comes from a slight difference in the official datasheet from Espressif, and the datasheet translated by the community before Espressif realized how many of these chips they were going to sell.

The best evidence of 5V tolerant pins might come from real-world experience — if you can drive a pin with 5V for months on end without it failing, there might be something to this claim. It’s not definitive, though; just because a device will work with 5V input pins for a few months doesn’t mean it won’t fail in the future. So far a few people have spoken up and presented ESPs directly connected to the 5V pin of an Arduino that still work after months of service. If this is evidence of 5V tolerant design or simply luck is another matter entirely.

While the official datasheet from Espressif lists a maximum VIH of 3.3V, maximum specs rarely are true maximums — you can always push a part harder without things flying apart at the seams. Unfortunately, unless we hear something from the engineers at Espressif, we won’t know if the ESP8266 was designed to be 5V tolerant, if it can handle 5V signals reliably, or if 5V signals are a really good way to kill a chip eventually.

Lucky for us — and this brings us to the entire point of an Ask Hackaday column — a few Espressif engineers read Hackaday. They’re welcome to pseudonymously chime in below along with the rest of the peanut gallery. Failing that, the ESP8266 has been decapped; are there any die inspection wizards who can back up a claim of 5V tolerance for the GPIO? We’d also be interested in hearing any ideas for stress testing pin tolerance.

3D Printering: Non-Planar Layer FDM

Non-planar layer Fused Deposition Modeling (FDM) is any form of fused deposition modeling where the 3D printed layers aren’t flat or of uniform thickness. For example, if you’re using mesh bed leveling on your 3D printer, you are already using non-planar layer FDM. But why stop at compensating for curved build plates? Non-planar layer FDM has more applications and there are quite a few projects out there exploring the possibilities. In this article, we are going to have a look at what the trick yields for us.

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Editor Wars

As a rule, I try hard not to get sucked into religious wars. You know, Coke vs Pepsi. C++ vs Java. Chrome vs Firefox. There are two I can’t help but jump into: PC vs Mac (although, now that Mac has turned into Unix, that’s almost more habit than anything else) and–the big one–Emacs vs vi.

If you use Linux, Unix, or anything similar, you are probably at least aware of the violence surrounding this argument. Windows users aren’t immune, although fewer of them know the details. If you aren’t familiar with these two programs, they are–in a way–text editors. However, that’s like calling a shopping mall “a store.” Technically, that’s correct, but the connotation is all wrong.

Like most religious wars, this one is partly based on history that might not be as relevant as it used to be. Full disclosure: I’m firmly in the Emacs camp. Many of my friends are fans of vi–I try not to hold it against them. I’ll try to be balanced and fair in my discussion, unless I’m talking about my preference. I don’t have to be fair when it comes to my opinions. Just to be clear: I know how to use vi. My preference isn’t based out of not wanting to learn something new.

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Hands-on the AND!XOR Unofficial DEF CON Badge

DEF CON 24 is still about two weeks away but we managed to get our hands on a hardware badge early. This is not the official hardware — there’s no way they’d let us leak that early. Although it may be unofficial in the sense that it won’t get you into the con, I’m declaring the AND!XOR badge to be officially awesome. I’ll walk you through it. There’s also a video below.

Over the past several years, building your own electronic badge has become an impromptu event. People who met at DEF CON and have been returning year after year spend the time in between coming up with great ideas and building as many badges as they can leading up to the event. This is how I met the trio who built this badge — AND!XORAndrew Riley, and Jorge Lacoste — last year they invited me up to their room where they were assembling the last of the Crypto Badges. Go check out my guide to 2015 Unofficial DEF CON badges for more on that story (and a video of the AM transmissions that badge was capable of).

The outline is this year’s badge is of course Bender from Futurama. Both eyes are RGB LEDs, with another half dozen located at different points around his head. The microcontroller, an STM32F103 ARM Cortex-M0 Cortex-M3, sits in a diamond pattern between his eyes. Above the eyes you’ll find 16 Mbit of flash, a 128×64 OLED screen, and a reset button. The user inputs are five switches and the badge is powered by three AA batteries found on the flip side.


That alone makes an interesting piece of hardware, but the RFM69W module makes all of the badges interactive. The spring coming off the top of Bender’s dome is a coil antenna for the 433 MHz communications. I only have the one badge on hand so I couldn’t delve too deeply what interactive tricks a large pool of badges will perform, but the menu hints at a structure in place for some very fun and interesting applications.

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Hackaday Links: July 24, 2016

Right now HOPE is dying down, and most of the Hackaday crew will be filtering out of NYC. It was a great weekend. The first weekend in August will be even better. We’re going to DEF CON, we’ll have people at VCF West, and a contingent at EMF Camp. If you’re going to EMF Camp, drop a line here. There will be Hackaday peeps wandering around a field in England, so if you see someone flying the Hackaday or Tindie flag, stop and say hi.

Raspberry Pi’s stuffed into things? Not all of them are terrible. The Apple Extended keyboard is possibly the best keyboard Apple ever produced. It’s mechanical (Alps), the layout is almost completely modern, and they’re actually cheap for something that compares well to a Model M. There’s also enough space inside the plastic to fit a Pi and still have enough room left over for holes for the Ethernet and USB ports. [ezrahilyer] plopped a Pi in this old keyboard, and the results look great. Thanks [Burkistana] for sending this one in.

We’ve been chronicling [Arsenijs] Raspberry Pi project for months now, but this is big news. The Raspberry Pi project has cracked 10k views on, and is well on track to be the most popular project of all time, on any platform. Congrats, [Arsenijs]; it couldn’t happen to a better project.

A few months ago, [Sébastien] released SLAcer.js, a slicer for resin printers that works in the browser. You can’t test a slicer without a printer, so for the last few months, [Sébastien] has been building his own resin printer. He’s looking for beta testers. If you have experience with resin printers, this could be a very cool (and very cheap) build.

Anyone going to DEF CON? For reasons unknown to me, I’m arriving in Vegas at nine in the morning on Wednesday. This means I have a day to kill in Vegas. I was thinking about a Hackaday meetup at the grave of James T. Kirk on Veridian III. It’s about an hour north of Vegas in the Valley of Fire State Park. Yes, driving out to the middle of the desert in August is a great idea. If anyone likes this idea, leave a note in the comments and I’ll organize something.

Retrotechtacular: The Modern Telephone

We take recorded telephone messages for granted in these days of smartphones and VOIP. Our voicemail lives on an anonymous server in a data centre in the cloud somewhere, in a flash memory chip on our DECT base station, or if we’re of a retro persuasion, on a micro-cassette. Wherever we go, we now know our calls will not go unanswered.

Today’s subject takes us back to a time when automatically recording a phone call was the last word in high technology, with British Pathé newsreel piece from 1959 entitled “Modern Telephone”. Its subject is the Ansafone J10, one of the first telephone answering machines available on the British market. After featuring a fantastic home-made Meccano answering machine with turntable recording created by a doctor, it takes us to the Ansafone factory where the twin tape mechanisms of the commercial model are assembled and tested. Finally we get to see it in use on the desk of a bona fide Captain of Industry, probably about the only sort of person who could afford an Ansafone in 1959.

Part of the film’s charm comes not from the technology but from the glimpse it gives us of 1950s Britain sanitised for the newsreel. The clipped tones, leather armchairs and bookshelves, the coal fire and the engineer in a three-piece suit. The past is a foreign country; they do things differently there.

Take a look at the film below after the break, and never take your recorded calls for granted again.

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Fail of the Week: Ferrofluid

It’s more of a half-fail than a full fail, but [Basti] is accustomed to getting things right (eventually) so it sticks in his craw that he wasn’t able to fully realize his ferrofluid dreams (German, translated here). Anyway, fail or demi-fail, the project is certainly a lesson in the reality of ferrofluid.


We’ve all seen amazing things done with ferrofluid and magnets. How hard can it be to make an interactive ferrofluid wedding present for his sister? Where ferrofluid spikes climb up a beautifully cut steel heart in a jar? (Answer: very hard.)

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