Tag Archives: atmega328p

20170628_211524s

Itead Studio Sonoff SC Revisited

A few months ago I wrote about the Sonoff SC sensor hub by Itead Studio. It’s a device with a Sharp GP2Y1010AU0F [Aliexpress] dust sensor, a DHT11 humidity and temperature sensor, an LDR as light sensor and a mic. The sensors are driven by an ATMega328P microcontroller but there is also an ESP8266 on board for WiFi communication, a pretty standard set up when you have several sensors and the ESP8266 GPIOs are just not enough.

20170105_125851s

On the first post I already did a small mod to replace the DHT11 humidity and temperature sensor with a more accurate and pin compatible DHT22. Since then, several readers have contributed with code and ideas. My progress implementing and testing them is slow, so I though about writing a first post about some modifications I (and others) have done to the device.

So this is a work in progress post. At the moment, all the code for these modifications is in the dev branch of the repository.

This custom Sonoff SC firmware is released as free open software and can be checked out at my SonoffSC repository on Github.

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20170614_135212s

Solr: digital wrist watch

15 months ago. This is when I started working on this project. The Solr digital wrist watch is a clock that won’t work without a battery but it will neither work without sun. Even more: the vintage display is really cool but it’s hard to read outdoors. A complete nonsense. It is almost a joke and some might easily file it under the “useless projects” label.

But it’s still quite useful. Whether you don’t care about accuracy, or if you need an excuse to always be late. Or maybe you want your daughter to raise her eyebrowns and tenderly call you a “freak”. Either case I suggest you to proudly wear a Solr.

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20170426_224506s

Slices of a clock

There are so many ways to tell the time. DIYers have been doing clocks since the Ancient Egypt (obelisks lacked portability, thou). Every modern maker has a clock amongst her first projects. I have done some myself, including a fibonacci clock, a wordclock with a fancy green matrix effect and an unreleased project that hopefully will see the light someday soon.

But recently I came back to the idea behind the wordclock before, to extend it in different ways:

  • Replace the ATMega328P with an ESP8266 (NTP support and user interaction)
  • Smaller sizes (8×8 LED matrices)
  • Smaller PCB, less buttons
  • Add buzzer for alarms
  • Replace the 3D printed part with a wooden grid cut in laser
  • Completely closed enclosure, better presentation
  • Fix some issues with the original board (like the lack of a beefy capacitor across the LED matrix power lines).

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20170105_125851s

Sonoff SC with MQTT and Domoticz support

Last December Itead Studio updated their Home Automation product line with a new and different product. The main difference is that it doesn’t have a relay and it’s mainly sensors and no actuator (if we don’t define a notifying LED as an actuator). The Sonoff SC is a sensor station that packs a DHT11 temperature and humidity sensor, a GM55 LDR, an electret microphone with an amplifier circuit and a Sharp GP2Y1010AU0F [Aliexpress] dust sensor in a fancy case that looks like it was originally meant for a speaker.

The device is packs an ESP8266 as expected and is compatible with the eWeLink app. But, such a collection of sensors, with 3 of them having analog interfaces, cannot be run from the single-ADC ESP8266 so Itead has thrown in a good old ATMega328P to drive the sensors and report the Espressif with the data.

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Wordclock with Green Matrix effect

Clocks are top projects for the maker community. There are tons of different ways to show or tell time. Or write time. Wordclocks are a subset of them by its own. You can find other wordclocks at instructables, for instance, or buy one from thinkgeek or from a local jewelry for just 450€. Mmm… well maybe that’s a little bit on the expensive side…

Recently I’ve been doing things with clocks and WS2812 LEDs (a.k.a. NeoPixels). My interest started with Philippe Chrétien’s Fibonacci Clock campaign at Kickstarter. I thought: “Wow! That’s cool AND freaking freak! I want one”. But the $100 and the instructable he himself had done before about building your own made me decide to try it. Anyway, that’s a different story.

That project led to this one. Because suddenly I happened to have 9 spare boards with an atmega328, an RTC, an SDCard slot, some nice buttons and the circuitry to drive a bunch of NeoPixels. I also happened to have a couple of LED matrices (you know, the kind of stuff you have in your bedroom drawer). So first I built a clone of the The Game Frame Pixel Art Project. It was great and my kids loved the pixelart. But I’m not going to talk about that project either.

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