RGB shelf lights

 Hi! At most I don't have much time to post here. But I'm trying))

Here is a combination of my KSN20 RGB controller and shelf light endpoint repeaters.

At first, final result:

RGB controller

 

Hi! I like decoration lights, so RGB controllers are "must have" devices for me =)

I decided to make module system, so for any light power I need only different type of repeaters instead of making new controller board for each purpose.

So this is main RGB controller board designed for my KSN20 CAN network:

UPS for smart home =)

 Hi! During apartment renovation I've routed 12V supply wires to all rooms. For a several years this worked without UPS and everything was fine. Recently I've got used Back-UPS CS 500 and finally decided to upgrade power system.

I have a metal electric route box installed at storage room, but inner size of it is too small to fit UPS. So UPS was disassembled and mounted into this box =)

I've surprised that control board has same mounting hole position as main board, so they perfectly fit together.

On these photos I didn't yet connect AC mains and 12V output wires, just test UPS run on battery.

Back to work

 Since 2018 I didn't wrote any posts (was busy with family).

Now I'm collecting new materials for posts related to smart home (my long R&D pet project).

Some words about it.

Several years ago I've decided to make my flat smart. But most of devices in production didn't fit my requests and expectations. I want to have full control over device behavior and independence of external cloud services (for scenarios, etc.).

I remember Google cloud failure, when a lot of people couldn't ever switch on/off lights or heating. I don't like wireless technologies related to other than outdoor temperature sensors, also wireless communication may be a honey target for hack. So, critical systems must be wired and isolated from any external intruders.

At 2017 I made first version of module network. UART over current loop. It was slow, really slow. Even on 4800 baud due to slow optocoupler turn-off (~150nS falling and ~1.2mS rising). Version 2020 uses CAN over old current loop, I've improved transceiver schematic that reduced transition delays to ~33nS falling and ~85nS rising edge, so overall baud rate is now 115200 without any packet loss. Also migrating to CAN gave me a freedom of multi-mastering nodes. Also current loop works fine with mixed topology (already tested on overall >100m cable with stubs 5-12m, even not twisted pair).

Yes, I'm going to make support for wireless nodes later. My choice now is RFM69 868MHz due to low bandwith usage (2.4GHz is very noisy now) and hardware AES encrypt engine.

Global profit of this work is that system can work even gateway is down. Most links and node configuration can be made once at install. Gateway/local cloud make this system smart, but if it's down, you can use all devices locally. All nodes have duplicate IO ports for generic switches/buttons or remote panel support.

When I look at modern smart home devices it seems like marketers are making them for sales, not people. 

So I'm trying to make smart home in old school style, where reliability, security and convenience are at first place.

If you want to look some photos, follow me at Instagram @kabansanych. I didn't make special tag for project, it will come soon.

UPD: New tag for Instagram #kssmarthome

Greets to all, Kabanski.

Another WS2812b VU Meter (Tiny version)

Hello friends!
About a month ago I bought several pieces of WS2812b LED strip. Why not make another VU meter?
I decided to make mini VU meter for single channel which can fit to CFL lamp base.

Cheap LED string rework (220VAC to 12VDC)

Hi friends!
Before New Year I've searched for a multicolor LED strings to decorate my home. But there was a problem. All strings at our stores must be powered from mains 220VAC. But there are some places at home without mains power outlets due to safety and 12VDC only. And the other reason is poor quality of most these products. Some of them are really dangerous and can burn without any visible reason.
So I decided to make some rework of a cheap LED string.

Click on any photo for full size.

60+60 series LED's work with 12VDC supply

Thermal transfer paper DIY PCB test

Hi!
Some days ago I've got another pretty thing from Aliexpress: thermal transfer paper for PCB DIY.
After making some boards with 0.5mm traces with perfect quality, I decided to test capability of this paper and my printer (HP 1020). Main goal was to create home made PCB with 0.25mm traces and 0402 components =)
So here is a test board after etching in ferric chloride:

Left side: 0.33mm traces with ~0.3mm spacing. Right side: 0.25mm traces, ~0.2mm spacing, one 0603 and two 0402 components.

Let's have a close look (click for large images):

Close to perfect for home DIY! Link to Ali store if you're interested.

MAX7219 Library for 8-bit AVR

Hi friends!
Yesterday I've got my 32x8 matrix module from Aliexpress.
I don't understand need of C++ usage in low-memory chips (most of all I'm using Attiny2313, Atmega48 and Atmega88), so I decided to write my own C library for 8-bit AVR's.

Because I have matrix module, digit mode for MAX chips was not tested.

Features:

• Per-pixel draw
• Simple buffer scroll function
• String render (latin+cyrillic variable character width font included)
• Easy to implement text scroll
• Support for both Flash and RAM string sources

Please note: library uses alpha version of AVR SPI library based on Stefan Engelke's code (included). Software and USI SPI not tested.

Here is Atmel Studio 6.2 project:

Download from Google Drive

PixelImage 0.4.51

New build of my image converter for embedded projects: *0.4.51* (Windows OS)

PixelImage

New feature: *Color calculator* (RGB,HSV to RGB565 and vice versa)

What's new:

* Changed row alignment rules (read compatible with previous version).
* Removed 4-byte row alignment for flash bitmap export (padding affects RA8875 DMA compatibility).
* Added Color calculator (RGB,HSV to RGB565 and vice versa).
* Bunch of small fixes.

Download at SourceForge

RA8875 LCD Flash share with Arduino

Hi!
For some time I have fun with 7" LCD display from Waveshare built on RAiO RA8875 controller chip. One of RA8875 great features is DMA support to load images from onboard flash chip.
Real trouble that there is no way to reprogram flash chip after soldering it to board.
Thanks to Waveshare engineers made header for dedicated flash SPI interface! There is no need to solder flash chip to display PCB, you can connect it to this header.

Idea! RA8875 does not use dedicated SPI all the time, only while DMA transfer is active. So why not share flash chip between two SPI buses: RA internal and Arduino?

There are cool IC's: 74LVC1G3157, single analog/digital SPDT switches. So, almost all time flash chip is connected to RAiO SPI, but when needed, it can be switched to Arduino's SPI bus. Switch control pins are connected to Arduino's CS pin.