Moving The Snail Mail To WiFi

June 7, 2023 by Matthew Carlson 22 Comments

[Zak] loves getting a notification on his phone when he gets physical mail. Enough to wire his mailbox slot with an ESP8285 to send him alerts. Previously, [Zak] used a cellular-based solution as the mailbox slot was not within WiFi range. However, the network provider for the A9G GPRS module decided to move to different towers, and suddenly the module didn’t work. Unable to find a provider that had sensible pricing, he got to work redesigning the module.

The mailbox was now in a WiFi network range, meaning he no longer had to use cellular. This dramatically simplifies the design and uses an ESP-M2 module (think ESP8266 but with embedded flash). To maximize battery life, the ESP is entirely off most of the time. A reed switch triggers a 74LVC1G98 NAND gate with an inverted input. This enables the 3.3 voltage regulator. A 4uF capacitor holds the voltage regulator on for 716ms, giving the ESP8266 time to boot and drive the second pin of the logic gate so it can stay on. Once the web request completes (a call to a PHP server that takes 4-5 seconds, including WiFi association), it pulls the pin low, and the system powers off. With a custom server, [Zak] can include a few goodies, such as temperature and humidity from the SHT32-DIS sensor.

So far, the system has been chugging along for seven months and over 110 mail notifications and has only dropped 0.3v, suggesting that the battery should hold out for another year or two before recharging. The code and schematics are up on GitHub. We love the low-power focus and the handy circuit explanation that makes it easy to use in other projects.

ExpressLRS: Open Source, Low Latency, Long Range RC Protocol

January 19, 2021 by Danie Conradie 42 Comments

One of the major choices a newcomer to the RC flying hobby must make is on the RC link protocol. To add the list of choices (or confusion) there is now a new open-source, low latency, and long-range protocol named ExpressLRS.

ExpressLRS’s claim to fame is high packet rates of up to 500 Hz, with plans for 1000 Hz, and latency as low as 5 ms. Long-range testing has pushed it out to 30 km with a flying wing (video below), but this is not unheard of for other protocols. Most modern RC protocols run either in the 2.4 GHz or 915/868 MHz bands, with the latter having a definite advantage in terms of range.

ExpressLRS has options to run on either band, using Semtech SX127x (915/868 MHz) or SX1280 (2.4 GHz) LoRa transceivers, connected to STM32, ESP32, or ESP8285 microcontrollers. The ESP microcontrollers also allow software updates over Wi-Fi.

We’re excited to see an open-source competitor to the proprietary protocols currently dominating the market, but several open-source protocols have come and gone over the years. Hardware availability and compatibility is a deciding factor for a new protocol’s success, and ExpressLRS already has an advantage in this regard. Existing Frsky R9 transmitters and receivers, and Immersion RC Ghost receivers are compatible with the firmware. There are also DIY options available, and the GitHub page claims that several manufacturers are working on official ExpressLRS hardware.

If you’re already into the RC hobby, and you have compatible hardware lying around, be sure to give it a try and give some feedback to the developers! One scenario we would like to see tested is high interference and congested band conditions, like at RC flying events.

All the source code and hardware designs are available on GitHub, and there are active community discussions on Discord. Continue reading “ExpressLRS: Open Source, Low Latency, Long Range RC Protocol” →

Gyroscopic Wi-Fi LED Die Is Pretty Fly

March 23, 2020 by Kristina Panos 9 Comments

As cool as sculptural LED cubes are, the only thing you can really do is look at them. They’re not going to stand up to a lot of handling, and as tedious as it is to bend all those leads when building them, you probably wouldn’t want to mess with them anyway.

LED dice on the other hand are robust, blinky playthings with many possibilities, especially if they have a gyroscope and wireless control like the one [moekoe] built. Inside this tiny 25cm³ die is the equally small ESP8285-01F, which lets [moekoe] control the rainbow light show with a Blynk app.

As you will see in the excellent build video that makes this build look challenging instead of impossible, the cube gets permanently sealed up with solder joints. Most but not all of these transfer power, ground, and data around the faces.

Once the cube is together, [moekoe] uses pogo pins to program it, and can charge the little LiPo inside through contact pads. We love the idea of using a cubical printed jig to help solder the PCB edges together, but not as much as we love [moekoe]’s home-brewed SMT soldering setup.

If you want an easier way to make sculptural LED cubes, build yourself a lead-formin’ machine.

Continue reading “Gyroscopic Wi-Fi LED Die Is Pretty Fly” →

Flashing Sonoff Devices With Tasmota Gets Easier

February 25, 2020 by Donald Papp 18 Comments

Tasmota is an alternative firmware for ESP boards that provides a wealth of handy features, and [Mat] has written up a guide to flashing with far greater ease by using Tasmotizer. Among other things, it makes it simple to return your ESP-based devices, like various Sonoff offerings, to factory settings, so hack away!

Tasmotizer is a front end that also makes common tasks like backing up existing firmware and setting configuration options like, WiFi credentials, effortless. Of course, one can’t really discuss Tasmotizer without bringing up Tasmota, the alternative firmware for a variety of ESP-based devices, so they should be considered together.

Hacks based on Sonoff devices are popular home automation projects, and [Mat] has also written all about what it was like to convert an old-style theromostat into a NEST-like device for about $5 by using Tasmota. A video on using Tasmotizer is embedded below, so give it a watch to get a head start on using it to hack some Sonoff devices.

Continue reading “Flashing Sonoff Devices With Tasmota Gets Easier” →

Adding Energy Use And Cost To “Laundry Done” Notifications

November 3, 2018 by Donald Papp 29 Comments

Some time ago [Xose Pérez] got interested in generating a notification when his washer had completed a cycle, and now with added features like reporting power usage and cost, he’s put it all together into a Node-Red node that makes it easy to modify or integrate with other projects.

[Xose] started this journey with a Laundry Monitor he created that effectively used cheap hardware (and his own firmware) to monitor his washing machine’s current usage. That sensor was used as the basis for sending notifications informing him whenever the appliance’s cycle was done. Since then, he has continued to take household power monitoring seriously, and with a bit of added work can not only tell when a given appliance has been started and stopped, but can also summarize the energy usage and cost of the appliance, making the notifications more useful. The package is named node-red-contrib-power-monitor and is also hosted on GitHub.

Cheap WiFi-enabled smart switches are making it possible for even the dumbest of appliances to join the Internet of Things, so don’t ignore [Xose]’s complementary work on ESPurna, which is an alternative open-source firmware for a wide variety of ESP8266 and ESP8285 based smart switches, lights and sensors.

Custom Lightbulb Firmware

October 1, 2017 by Lewin Day 15 Comments

The Internet of Things is developing at a rapid pace, as hobbyists and companies rush to develop the latest and greatest home automation gear. One area of particular interest to some is lighting – yes, even the humble lightbulb now comes with a brain and is ripe for the hacking.

[Tinkerman] starts by doing a full disassembly of the Sonoff B1 lightbulb. It’s a popular device, and available for less than $20 on eBay. Rated at 6 watts, the bulb has a heatsink that is seemingly far larger than necessary. Inside is the usual AC/DC converter, LED driver and an ESP8285 running the show. While this is a slightly different part to the usual ESP8266, it can be programmed in the same way by selecting the correct programming mode.

This is where it gets interesting – [Tinkerman] flashes the device with a custom firmware known as ESPurna. This firmware enables greater control over the function of the bulb, from colour choice, to speaking to the bulb over MQTT.

[Tinkerman] does a great job of walking through the exact steps needed to disassemble and reprogram the bulb, and touches upon the added flexibility given by the custom firmware. We love to see projects like this one, that give greater control over IoT devices and enable users to better integrate them with other systems.

New Part Day: Pluggable ESP Modules

September 1, 2017 by Brian Benchoff 52 Comments

Almost exactly four years ago, we came across a really neat module for sale on SeeedStudios. It was a $5 WiFi chip, able to connect your microcontroller project to the Internet with just a handful of wires and a few AT commands. This was the ESP8266, and it has since spawned an entire ecosystem of connected devices.

Now, there’s a new version of the ESP8266 that simply showed up on the Seeed website. Officially, it’s called the, ‘ESP8285 01M Wi-Fi SoC Module’, but you might as well start calling it ‘the Pluggable ESP module’. It’s the smallest ESP8266 module yet at 18mm square, and this one is designed to be plugged into a card-edge connector. It’s eighteen pins of wonder and 1MB of Flash, all ready to be stuffed into the next Internet of Things Thing.

The documentation for this module is sparse, and there isn’t even a mention of it on the AI Thinker website. That said, we can make some reasonable assumptions about what’s going on in this chip and what it can do. This module appears to be based on the ESP8285 SoC. Basically, it’s an ESP8266 with built-in 1MB SPI Flash. There are a handful of GPIOs available, and you should be able to build anything with this module that you could with other ESP8266 modules.

The highlight here is, of course, the card-edge connector. This is a module designed to be dropped into an existing product. You can program the module before hand, and assembly is a snap. The problem, though, is sourcing the relevant connector. It doesn’t look like Seeed has bothered to put a link to the right connector in the product description, although sourcing it shouldn’t be that much of a problem. The only question is if the card edge connectors on this module are hard gold (for multiple mating cycles) or just ENIG. Either way, if you’re plugging these modules into connectors dozens of times, you’re probably doing something wrong.