Sometimes Chinese manufacturers throw a mysterious, unlabelled, IC into their designs so we can spend a few hours trying to figure out what they are and what they do. It’s such fun! I’ve been playing with one of those this afternoon, trying to answer those questions but also trying to understand why! Why is that chip there? Why did someone decided she needed that chip there?
Some weeks ago a user of ESPurna asked me if the firmware supported Itead’s 1CH self-lock/inching board. My answer was “why not” since all Itead’s products are very much alike. Wrong. This one is different. Let me summarise why:
There is no entry in the Itead’s wiki for the device
There are no schematics, drawings, in the store
It uses (and brings out) a Songle SRD-05VDC-SL-C SPDT relay (there is only one other product using this relay in Itead Studio store)
The HLW8012 is single phase energy monitor chip by the chinese manufacturer HLW Technology. It features RMS current, RMS voltage sampling and RMS active power with an internal clock and a PWM interface in a SOP-8 package. You can buy it at Aliexpress for less than a euro a piece and the necessary components are fairly easy to source and quite cheap.
All in all it looks like a great IC to include power monitoring in your projects. I guess that is why Itead Studio chose it for the Sonoff POW, one of their newest home automation products. And of course I have a POW here in my desk and I’ve been playing with it this weekend. The goal is to support it in my Espurna firmware but first I wanted to know more about the HLW8012. I’ll write about the Sonoff POW in a different post later this week.
Last Thursday PunchThrough, the people behind the LightBlue Bean and Bean+ boards, released their new Bean Loader, the application that allows you to upload new sketches to your beans. The great news about this is that, for the first time (!!!) the Bean Loader supports Linux!!! Yeeeha!
So I quickly looked for my 4 Beans that have been sad and forgotten in a components box for the last 2+ years and put them to work. It was not smooth, but there is a happy ending. So keep reading.
Quick post from an old draft, mainly as documentation.
A 9600Hz oscillator circuit based on a 2.4576MHz crystal and a 74HC590 binary counter. The idea was to reproduce the set up from robotroom.com site with a bar crystal but I had some trouble making it work. The solution came from this document about crystal oscillator circuits that describes different circuits depending on the crystal frequency. Here you have the schema and a picture of the circuit:
9600Hz oscillator circuit
Prototyping it in a breadboard. The DSO Nano is out of focus but shows a 9.60kHz signal.
PCB etching is another big topic in the electronics DIY world. It’s something every electronics tinkerer ends up trying sooner o later. Even thou it’s a fairly simple procedure it requires some self confidence (or bravery) since it involves strong, smelly and hazardous chemicals.
Any etching procedure you read about can be described in 5 different steps: designing, transferring, etching, assembly and reuse or disposal. For every one of these five steps there are different options and there are thousands of web pages with instructions, recommendations, how-to’s… well, this is yet another one of those pages 🙂