Keeping An Eye On The Water Heater Pilot Light

January 21, 2021 by Danie Conradie 44 Comments

[WJCarpenter]’s gas water heater uses a small pilot light that needs to stay burning permanently to ignite the main burners as required. Four or five times a year, the pilot light goes out and needs to be manually lit. This involves an expedition from the upstairs bathroom to the basement, always in the early morning, after having spent a few fruitless minutes waiting for hot water. Having grown tired of this exercise, [WJCarpenter] built Water Watcher, a pilot light monitoring system with some ESPs and a light sensor.

Water Watcher consists of an ESP8266 connected to a light sensor taped to the inspection window of the water heater. It reports the status of the pilot light over MQTT to an ESP32-based M5 Atom Matrix in the main bedroom, which displays it using a 5×5 RGB matrix, as demonstrated after the break. Both ESPs run ESPHome, so programming is as easy as giving it a YAML config file. [WJCarpenter] tested a few different light sensors, until he found the TSL2591, which is sensitive to the right wavelengths and has enough dynamic range for watching a pilot light.

This might not be a complicated hack, but we do not doubt that it reduces frustration a bit on those fateful mornings. Be sure to check out the Water Watcher project page, it’s an entertaining read! Continue reading “Keeping An Eye On The Water Heater Pilot Light” →

Automated Balcony Shade Uses NFC

January 20, 2021 by Bryan Cockfield 3 Comments

[Udi] lives in an apartment with a pleasant balcony. He also has three kids who are home most of the time now, so he finds himself spending a little more time out on the balcony than he used to. To upgrade his experience, he installed a completely custom shade controller to automatically open and close his sunshade as the day progresses.

Automatic motors for blinds and other shades are available for purchase, but [Udi]’s shade is too big for any of these small motors to work. Finding a large servo with a 2:1 gear ration was the first step, as well as creating a custom mount for it to attach to the sunshade. Once the mechanical situation was solved, he programmed an ESP32 to control the servo. The ESP32 originally had control buttons wired to it, but [Udi] eventually transitioned to NFC for limit switch capabilities and also implemented voice control for the build as well.

While not the first shade controller we’ve ever seen, this build does make excellent use of appropriate hardware and its built-in features and although we suppose it’s possible this could have been done with a 555 timer, the project came together very well, especially for [Ubi]’s first Arduino-compatible build. If you decide to replicate this build, though, make sure that your shade controller is rental-friendly if it needs to be.

Continue reading “Automated Balcony Shade Uses NFC” →

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” →

On-Air Sign Helps Keep Your Broadcasts G-Rated

January 18, 2021 by Kristina Panos 7 Comments

Like many of us, [Michael] needed a way to let the family know whether pants are required to enter the room — in other words, whenever a videoconference is in progress. Sure he could hang a do not disturb sign, but those are easy to forget. There’s no need to worry about forgetting to change status because this beautiful wall-mounted sign can be controlled with Alexa.

Inside the gorgeous box made from walnut, curly maple, and oak is an ESP32, some RGB LEDs, and three MOSFETs. [Michael] is using the fauxmoESP library to interface the ESP32 with Alexa, which emulates a Phillips Hue bulb for the sake of using a protocol she already knows. [Michael] can change the color and brightness percentage with voice commands.

The sign is set up as four different devices — one default, and one for each color. Since talking to Alexa isn’t always appropriate, [Michael] can also change the color of the LEDs using sliders on a website that’s served up by the ESP. Check out the full build video after the break.

Need something quick and dirty that works just as well? Our own [Bob Baddeley] made a status indicator that’s simple and effective.

Continue reading “On-Air Sign Helps Keep Your Broadcasts G-Rated” →

ESP32 Soil Monitors Tap Into Ultra-Low Power Mode

January 14, 2021 by Tom Nardi 26 Comments

Soil moisture sensors are cheap and easy to interface with, to the point that combining one with an Arduino and blinking an LED when your potted plant is feeling a bit parched is a common beginners project. But what about on the long term? Outside of a simple proof of concept, what would it take to actually read the data from these sensors over the course of weeks or months?

That’s precisely the question [derflob] recently had to answer. The goal was to build a device that could poll multiple soil sensors and push the data wirelessly into Home Assistant. But since it would be outside on the balcony, it needed to run exclusively on battery power. Luckily his chosen platform, the ESP32, has some phenomenal power saving features. You just need to know how to use them. Continue reading “ESP32 Soil Monitors Tap Into Ultra-Low Power Mode” →

New Part Day: Espressif ESP32-S3

January 9, 2021 by Jenny List 53 Comments

Since Espressif Systems arrived in our collective consciousness they have expanded their range from the ESP8266 to the ESP32, and going beyond the original WROOM and WROVER modules to a range of further ESP32 products. There’s a single-core variant and one that packs a RISC-V core in place of the Tensilica one, and now they’ve revealed their latest product. The ESP32-S3 takes the ESP to a new level, packing as it does more I/O, onboard USB, and an updated version of the two Tensilica cores alongside Bluetooth version 5. It’s still an ESP32, but one that’s more useful, and it’s worth a closer look because we expect it to figure in quite a few projects.

Espressif's block diagram for the chip. — Espressif’s block diagram for the chip.

Sadly the data sheet does not seem to have been released, but we do have some tidbits to consider. Espressif are anxious to tell us about its “AIOT” capabilities thanks to the vector instructions in the EXTensa LX7 cores (PDF) that were not present in the previous model’s LX6. They claim that this will speed up software neural networks; this does have an air of marketing about it but we’ll withhold judgement until we see it in use. The new core certainly will offer a performance improvement across the board though, which should be of interest to all ESP32 developers. Meanwhile the ultra-low-power core that existing ESP32 developers will be familiar with remains.

Then there is that USB support, which appears in the feature block diagram but has little information elsewhere. It’s listed as USB OTG which raises the possibility of the ESP32 being the host, but what it should also bring is the ability to emulate other USB devices. We’ve seen badges mount as WebUSB devices using STM32 clones as peripherals for an ESP32, but in future these tricks should be possible on the Espressif chip itself.

Probably the most anticipated piece of the new device’s specification comes in the addition of 10 new I/O lines. This has historically been a weakness of the ESP line, that it’s an easy chip with which to run out of available pins. These extra lines will make it more competitive with for example the STM32 series of microcontrollers that have larger package options, and will also mean that designs can have more in the way of peripherals without the use of port expanders.

In summary then, the latest member of the ESP32 family delivers a significant and useful update, and brings some of the features first seen in the single core version to the more powerful line of chips. Sadly it doesn’t have the hoped-for on-chip RAM boost, but it brings enough in the way of new capabilities to be of interest. At the moment it doesn’t look like the ESP32-S3 is available to order, but we hope to have engineering samples soon and should be bringing you a hands-on report in due course.

DIY Laser Tag System Comes With All The Bells And Whistles

January 7, 2021 by Danie Conradie 29 Comments

While VR is becoming really immersive, it still can’t compete with a game of good old laser tag to get the blood pumping and spending quality time with friends. [Xasin] has been working on a DIY laser tag system for a while now, and it has grown to include an impressive array of features and customizability.

Named LZRTag, the project started back in 2018 with simple ATmega328 based prototypes on breadboards. It has since evolved to a fully-featured system with ESP32s in the 3D printed pistol communicating with a Raspberry Pi/Linux game server over MQTT. Each pistol also features an accelerometer, I2S audio amp and speaker for game sounds, and WS2812 RGP LEDs for light effects. IR Lasers are used as emitters to target wearable IR receivers with more RGB LEDs wired to the pistol.

A Ruby server on a Linux machine takes care of all the communications, game management, shot validation, and scoring. It can handle up to 255 players and is designed to be extremely customizable for game modes, weapons classes, or any other feature you would like to have. [Xasin] has also created IR beacons to add even more possibilities, such as capture the flag, safe zones, and revive zones.

We really like the flexibility of the system, and it would make an awesome group project for a hackerspace. You could also add a shock module to motivate players a bit more to avoid getting shot. If you want more gun, take a look at the laser tag rifle with a HUD we featured earlier in the year Continue reading “DIY Laser Tag System Comes With All The Bells And Whistles” →