Replacing An ESP8266 Clone With The Real Thing

The first time [konbaasiang] ordered some ceiling LED lights from Tuya, he was pleased to find they contained an ESP-12F that could easily be flashed with a different firmware. So when he ordered 30 more of them at a cost of nearly $900 USD, you can understand his frustration to find that the popular WiFi-enabled microcontroller had been swapped out for a pin-compatible clone that Tuya developed called the WB3L.

Some people would have just chalked this one up to bad luck and used the Tuya-supplied software to control their new lights, but not [konbaasiang]. Since the new chip was outwardly identical to the ESP8266, he decided to take the nuclear option and replace them with the genuine article. With a comfortable spot to work from and a nice microscope, he started on his desoldering journey.

Now it would have been nice if he could have just dropped in a real ESP-12F and called it a day, but naturally, it ended up being a bit more complex than that. The WB3L apparently doesn’t need external pull up and pull down resistors, but [konbaasiang] needed them for the swap to work. He could have come up with some kind of custom adapter PCB, but to keep things simple he decided to run a pair of through hole resistors across the top of the ESP-12F for GPIO 1/2, and use a gingerly placed SMD resistor to hold down GPIO 15.

[konbaasiang] reports that all 30 of the lights survived the transplant and are now running his own  homebrew firmware. While this story had a happy ending, it’s still a cautionary tale. With a growing trend towards replacing the venerable ESP8266 with cheaper and less hacker-friendly silicon, buying IoT hardware with the intent to replace its firmware is likely to get riskier in the near future.

18650 Brings ESP8266 WiFi Repeater Along For The Ride

We’re truly fortunate to have so many incredible open source projects floating around on the Internet, since there’s almost always some prior art you can lean on. By combining bits and pieces from different projects, you can often save yourself a huge amount of time and effort. It’s just a matter of figuring out how all the pieces fit together, like in this clever mash-up by [bethiboothi] that takes advantage of the fact that the popular TP4056 lithium-ion battery charger module happens to be almost the exact same size of the ESP-01.

By taking a 3D printed design intended to attach a TP4056 module to the end of an 18650 cell and combining it with an ESP8266 firmware that turns the powerful microcontroller into a WiFi repeater, [bethiboothi] ended up with a portable network node that reportedly lasts up to three days on a charge. The observed range was good even with the built-in PCB antenna, but hacking on an external can get you out a little farther if you need it.

While it doesn’t appear that [bethiboothi] is using it currently, the esp_wifi_repeater firmware does have an automatic mesh mode which seems like it would be a fantastic fit for this design. Putting together an impromptu mesh WiFi network with a bunch of cheap battery powered nodes would be an excellent way to get network connectivity at an outdoor hacker camp, assuming the ESP’s CPU can keep up with the demand.

ESP8266-Powered Receipt Printer Puts RESTful API On Dead Trees

Taking his digital information into the real-world, [Davide Gironi] has built his own note transcriber from a point-of-sale receipt printer and an ESP8266.

You’ve seen these receipt printers at the order window of restaurants. A server puts in an order from any of the machines throughout the restaurant and a paper summary spits out for the chef line to start in on (and even cuts itself off from the roll).  Why shouldn’t we have this convenience in our own lives?

The printer communicates using a variant of the Epson Standard Code for Printers, for which [Davide] has written a library and thankfully shared the code. Adding an ESP8266 using a couple voltage regulators and some passive components makes this wireless, except for power. It has all the fun bells and whistles to set up the WiFi credentials and once running, just push the button on the base and it’ll spit out your data.

But wait, where is that data coming from? The web-based settings page lets you configure a URI to the RESTful source of your choosing. (XKCD has one, don’t they?) It also lets you configure header, footer, error messages, and of course your company hacker logo.

One of our favorite receipt-printer moments was when Hackaday editor of yore [Eliot Phillips] brought a selfie receipt printer to Supercon. We couldn’t find any pictures of that one, so we’ll leave you with the excellent hack [Sam Zeloof] pulled off by cramming one of these into a Polaroid camera.

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Roomba Gets Alexa Support With An ESP8266 Stowaway

The modern home is filled with plenty of “smart” devices, but unfortunately, they don’t always speak the same language. The coffee maker and the TV might both be able to talk to your phone through their respective apps, but that doesn’t necessarily mean the two appliances can work together to better coordinate your morning routine. Which is a shame, since if more of these devices could communicate with each other, we’d be a lot closer to living that Jetsons life we were promised.

Luckily, as hardware hackers we can help get our devices better acquainted with one another. A recent post by [MyHomeThings] shows how the ESP8266 can bridge the gap between a Roomba and Amazon’s Alexa assistant. This not only allows you to cheaply and easily add voice control to the robotic vacuum, but makes it compatible with the Amazon’s popular home automation framework. This makes it possible to chain devices together into complex conditional routines, such as turning off the lights and activating the vacuum at a certain time each night.

The hack depends on the so-called Roomba Open Interface, a seven pin Mini-DIN connector that can be accessed by partially disassembling the bot. This connector provides power from the Roomba’s onboard batteries as well as a two-way serial communications bus to the controller.

By connecting a MP1584EN DC-DC converter and ESP8266 to this connector, it’s possible to send commands directly to the hardware. Add a little glue code to combine this capability with a library that emulates a Belkin Wemo device, and now Alexa is able to stop and start the robot at will.

We’ve seen this sort of trick used a few times before to add backdoor Alexa support to various gadgets, and it’s always interesting to see what kind of unusual hardware folks are looking to make an integral part of their smart home.

Hands-On: The RISC-V ESP32-C3 Will Be Your New ESP8266

We just got our hands on some engineering pre-samples of the ESP32-C3 chip and modules, and there’s a lot to like about this chip. The question is what should you compare this to; is it more an ESP32 or an ESP8266? The new “C3” variant has a single 160 MHz RISC-V core that out-performs the ESP8266, and at the same time includes most of the peripheral set of an ESP32. While RAM often ends up scarce on an ESP8266 with around 40 kB or so, the ESP32-C3 sports 400 kB of RAM, and manages to keep it all running while burning less power. Like the ESP32, it has Bluetooth LE 5.0 in addition to WiFi.

Espressif’s website says multiple times that it’s going to be “cost-effective”, which is secret code for cheap. Rumors are that there will be eight-pin ESP-O1 modules hitting the streets priced as low as $1. We usually require more pins, but if medium-sized ESP32-C3 modules are priced near the ESP8266-12-style modules, we can’t see any reason to buy the latter; for us it will literally be an ESP8266 killer.

On the other hand, it lacks the dual cores of the ESP32, and simply doesn’t have as many GPIO pins. If you’re a die-hard ESP32 abuser, you’ll doubtless find some features missing, like the ultra-low-power coprocessor or the DACs. But it does share a lot of the ESP32 standouts: the LEDC (PWM) peripheral and the unique parallel I2S come to mind. Moreover, it shares the ESP-IDF framework with the ESP32, so despite running on an entirely different CPU architecture, a lot of code will run without change on both chips just by tweaking the build environment with a one-liner.

One of these things is not like the other

If you were confused by the chip’s name, like we were, a week or so playing with the new chip will make it all clear. The ESP32-C3 is a lot more like a reduced version of the ESP32 than it is like an improvement over the ESP8266, even though it’s probably destined to play the latter role in our projects. If you count in the new ESP32-S3 that brings in USB, the ESP32 family is bigger than just one chip. Although it does seem odd to lump the RISC-V and Tensilica CPUs together, at the end of the day it’s the peripherals more than the CPUs that differentiate microcontrollers, and on that front the C3 is firmly in the ESP32 family.

Our takeaway: the ESP32-C3 is going to replace the ESP8266 in our projects, but it won’t replace the ESP32 which simply has more of everything when we need it. The shared codebase and peripheral architecture makes it easier to switch between the two when we don’t need the full-blown ESP32. In that spirit, we welcome the newcomer to the family.

But naturally, we’ve got a lot more to say about it. Specifically, we were interested in exactly what the RISC-V core brought to the table, and ran the module through power and speed comparisons with the ESP32 and ESP8266 — and it beats them both by a small margin in our benchmarks. We’ve also become a lot closer friends with the ESP-IDF SDK that all of the ESP32 family chips use, and love how far it has come in the last year or so. It’s not as newbie-friendly as ESP-Arduino, for sure, but it’s a ton more powerful, and we’re totally happy to leave the ESP8266 SDK behind us.

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Old Gas Meter Gets Smart With The ESP8266

Measuring the usage of domestic utilities such as water, gas or electricity usually boils down to measuring a repetitive pulse signal with respect to time. To make things easy, most modern utility meters have a pulsed LED output, which can be used to monitor the consumption by using an external optical sensor. But what do you do if your meter isn’t so cooperative?

That’s exactly what [Francesco] had to figure out while developing the non-invasive gas tracking system he calls ESPmeter. His meter might not have an LED, but it did have a magnet attached to the counter disk which activated an internal hall sensor. With some hacking, he was able to attach an external Hall-effect sensor to pick up this magnet and use the signal to monitor his daily gas consumption.

A big stumbling block in such projects is the issue of powering the device for an extended period, and remembering when it’s time to change the batteries. With the clever use of commonly available parts, he was able to reduce power consumption allowing three AA batteries to last about a year between changes. For one thing, he uses an ATtiny13 to actually read the sensor values. The chip doesn’t run continuously, its watchdog is set at 1 Hz, ensuring that the device is woken up often enough so that it has time to power up the sensor and detect the presence of the magnet. Battery voltage is also measured via a voltage divider connected to the chip’s ADC pin.

At regular intervals throughout the day, the ESP8266 polls the ATtiny13 to pull the stored sensor pulses and voltage measurement. Then at midnight, the ESP transmits all the collected data to a remote server. Overall, this whole scheme allows [Francesco] to reliably gather his gas consumption data while not having to worry about batteries until he gets the low voltage notification. Since the data visualization requirements are pretty basic, he is keeping things simple by using Plotly to display his time series data.

If you are unfortunate enough to have an even older meter which doesn’t use optical or magnetic rotation sensing, you can use a disassembled mouse to keep track of the Gas Meter.

ESP8266 Socket Is A Snap-Fit, Breadboard-Friendly Wonder

It all started with wanting to program an ESP-12 variant of an ESP8266 module without involving any solder. Displeased with all the socket offerings on Thingiverse, [tweeto] set out to design their own breadboard-friendly snap-fit socket.

This certainly looks like a handy solution. All you have to do is print the thing, add all the wires, and stick your ESP in there. Even that wire is easy to find; [tweeto] used 0.8 mm paper clips which are sturdy, conductive, and haunting the darkest corners of every desk drawer. They’re also a little bit on the thick side, so [tweeto] plans to test out 0.6mm copper wire in the future.

The challenge with this type of print is to design something that will stand up to repeated breadboardings without losing legs or falling apart. [tweeto]’s elegant solution is a tiny groove for each wire in the bottom of the socket — it keeps the wire in place by countering the play caused by inserting it into and removing it from a breadboard. See how [tweeto] bends the paper clips in the short video after the break.

There’s more than one way to use 3D printing to your circuit-building advantage, even in permanent circuits — just take a look at this PCB-free Arduboy.

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