All posts by Felix Fratila

Fire lamp

I found a lot of intersting ideas on the internet on how to make a fire simulation lamp using WS2812c programmable leds and Arduino. So I had to try this too. Spice up the romance that is 😉

I found a strip with leds very close put together, so the effect would also look nice.  Everything is powered by a 5v power bank, so you can just take it with you wherever you want to set a romantic mood 😉

To do: make a lamp with white glass around the electronics to diffuse the light from the leds so not every single one is visible.

I used the NeoPixel library to program the leds, also I used parts of code I found on the internet and adapted it. Also a Arduino Nano was enough to control all 140 leds alligned in groups of 20.

Also if someone is interested in the code, here it is attached. Of course it can be improved a lot. I also plan to make multiple modes of this lamp to be able to select by button fire, lava lamp, snow flakes, etc…

Outdoor christmas decoration

So I got theese outdoor Christmas leds from China, solar powered ones. Like I expected, the lack of sun in Germany, especially on that side of the house where I intended to put them, was a big issue.

Another slight issue was that the children were so happy about the first snow, that they didn’t see it and ripped of the wire.

So my solution was to put everything on 4 AA batteries, and also on a Attiny85 microcontroller, and program the leds to automatically light up at 18:00 o’clock and turn off at 22:00.

Yeelight Strip Hacking

Everyone who knows me a little bit, knows how crazy I am about Xiaomi products. No other company I know offers such a wide spectrum of products, so good quality of components used to build theese products, and such great prices.

I recently bought a Yeelight LED strip to integrate in my Xiaomi Smart Home system. It is a high quality product, with many features. The only downside is the length of 2m. It is not bright enough for the whole living room. So I decided to do a little experiment: cut out the led strip and the power source, and solder a 5m strip and a more powerful power source.

Since I love theese products so much, this was very painful 🙂 but I did it anyway. The results were positive. I successfully replaced the LEDs with a 5m long 5050 RGB LED strip and a 5A power source. Everything still works with the app and the scenes. The only downside on this solution was that the colors were not exactly the same as I expected. Obviously the 5m strip was not the same quality as the ones from Yeelight. I will need to find some better ones.

Or just wait for the new Yeelight LED strip which will be 10m long I hear.

Halloween masks

I gotta take time more often for stuff like this. Anyway we decided this year we (me and my children) make our own halloween masks. My daughter decided to go for a witch and my son for baby Groot.

We started of with some basic masks I baught, and using tape and newspapers we shaped the rough form.

For everything to go faster I also bought some Papermache which mixed with water resulted in a perfect molding stuff. When it gets dry it isn’t too heavy and it can be sanded with sandpaper.

So this is only the first rough form. Still a lot to be done here after it dries out…

Next step was to give them a base color to cover the surface. Later on light colors will be used to give them the real form.

Last touch was painting them in the final colors. Also the leaves for Baby Groot were made with PLA using a 3d pen. We also used UV colors for both so that under UV light tey would shine like the last picture below.

Automating Christmas Trees (Attiny/Arduino)

Christmas is coming and everyone gets out all decorations and lightnings from the basement. It’s a wonderfull time of the year to remember every light bulb from the lightning, which was broken last year, and when there was no time to fix it, etc.


Also to remember which decorations were not so appreciated. This is the case with our two little trees which we got for the childrens room. They had to be turned on every evening and off after going to sleep. An unnecessary process which I wanted to fix.

I remembered some time ago I controlled a simple light with a little Attiny85. This had to be done again.

I used a Arduino Uno as a programmer for the Attiny. I had to remember the whole process again, so I’ll better write it here for the future.

Arduino softare has in properties a field for the link to get additional board managers. There I added:

In the boardmanager I installed it. I uploaded AndroidISP into the Android Uno, connected the Attiny like in the picture, and then uploaded using the programmer the following code:

void setup() {  pinMode(0, OUTPUT); }
void loop() {
  digitalWrite(0, HIGH);
  digitalWrite(0, LOW);

A simple program to turn the tree on for 6 hours and off for 18. This means if started in the evening at 18:00, it will always turn on at 18:00 and off at 00:00.

The electronics in the tree couldn’t have been easier to understand and adapt.

Didn’t test it yet, but I hope it works good enough even using the Attiny internal clock.

3d drawing pen

With this I think I hit the jackpot. No more buying toys for my kids. They now should be able to make their own … 🙂

With all the fuss around 3d printing, 3d doodler, 3d pens, … too much 3d theese days 🙂 I really got in the mood to try something without spending a couple of hundreds. So like every other dad does, I found the excuse: buy it “for the kids” 😉

I decided to go with a 3d pen, more exactly this one. I thought about this one and maybe I should have taken this one, but no hurry, there are still a lot of events coming “for the kids” 🙂

The first tries were not so lucky. A lot of fun, but clearly some amount of handywork is needed.

But like always with the kids, with more skill comes more fun. So the next tries looked better and better.

The last was a fully functional crane with a crank used to lift objects.

With time the toys can look good enough not to end in some box and be forgotten. And while the kids have fun, the parents can chill 😉

Handbag sewing

So my daughter got a toy sewing machine, a little battery powered one, much more functional than I thought.

So after trying to remember how it’s done, we started to develop a pattern based on a handbag she saw on the internet, put it on paper, and cutting out the material. Step by step we have got it. She sewed the most of it. Still learning, but we got as far as we could. She still wants to stick some figurines on it, which she will make soon with a 3D pen (see my other post) …

Next project ist some stuffed toys …

Robot cleaner flock (Step 1)

OK, now this is really only the first of many steps of a project which will for sure take more than my other ones.

Nowadays a robot cleaner is no big news, many have them already, and a lot of companies try to build them and do a better job than the competition. They are getting also cheaper and cheaper, and are affordable enough to try.

But the biggest problems still persist. The movement algorithms are still pretty basic, the robot cleaner has no clue about the layout of the room, where he already was, and what it still needs to clean. Also more complex places like table and chairs (every time in another position) are still handled more or less random, and not precise enough due to the size of the robot cleaner.

So for my project I had this idea: what about a flock or swarm of robot cleaners of smaller size than usual, which are aware of the room layout, learn the changes in the room layout, and most of all aware of each other, and of the paths the other ones already walked (which reduces the cleaning redundancy of portions of the floor)

The to-do list ist quite big so lets just start:

  1. Start off with a simple robot, which connects via WiFi to the router or PC.
  2. Decide on the sensors needed to map the room, the path and the obstacles
  3. Build at least two more robots.
  4. Build a “Mothership” application on the PC, which connects all of them and centralizes the information from each of them

Starting with the first part, I decided to go with a simple DIY package, the NodeMCU Lua ESP8266MOD car which consists of the NodeMCU dev board, the ESP8266 wi-fi module to connect to other devices as access point or directly to the router. Also a motor driver, wheels and motors are available, so the start was simple.

For now the car is in AP mode, it lets a smartphone connect to it and send commands from an app.

Next I will connect the car to the router and try to control it from the PC via the router.

Still a lot to do. I will post my progress, as soon as it’s worth mentioning 😉  …