DIY and Tinkering

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Soil Moisture

Winter in my area is not a snowy winter dream. Maybe that’s why I am not very much into winter. Winter is a season I always wait to pass. While waiting, I prepare for spring. And this spring I want to build a solution for a problem we always have in summer: Our strawberry plants shrivel to death during our summer holidays. So I decided to build a automatic watering machine for them.
My first step is developing a soil moisture sensor. I checked out different implementations and found that capacitive sensors are best as they do not emit unhealthy things into the soil.


Currently I am preparing the bird nest cam. The ESP32 cam can be powered on two levels: On 3.3V or on 5V. In several articles on the web I found the information that the ESP32 Cam does sometimes not work properly when powered on 3.3V. Therefore I decided to power it on 5V. The LiPo cells of my old MacBook deliver 3.7V. So I needed a step up converter also called boost converter.

Recycling old batteries

I found my 2007 MacBook in the attic and took it apart

MacBook 2007

I will try to re-use as many components as possible in my future projects, but first I’ll have to learn more about Apple’s components. I started with the battery. In its case are 6 LiPo cells. Unfortunately two of my cells are damaged, but that means 4 are left for further usage. Currently I am trying to charge them with the help of a TP4056 board and a 6V 200 mA solar panel. But to gather more data, I first needed to build a data logger.


The four remaining cells are in a good condition. It did several tests with them. I will use at least one of them as battery for my ESP32 cam.

Meanwhile I ordered a HDMI board at Amazon (LCD/HDMI-Karte für 12,1 Zoll / 33,8 cm B121EW03 V2 LTN121W3-L01 LTD133EX2X B133EW01 V4). With the help of this board I am able to use the display of my old MacBook as monitor of a Raspberry Pi4. I will build an Magic Mirror with those components.

Need something more complex…

The RC car project was nice. It showed me the principles of how to program in Arduino IDE and how to control engines. But I need something more complex…

My next projects will be either a small CNC machine or a smart LED lamp for my son. I know, DIY CNCs are as widely spread as my 4WD RC car project on the net, but most of them use existing libraries. I am thinking more on implementing my own protocol…

I also have many ideas for the lamp. First of all, I’d like to use an ESP32 controller, that would enable Bluetooth and Wifi usage. Then I am thinking about using Bluetooth audio, so I’d need an amplifier and speakers. Of course severals LEDs must be attached. The LEDs should be RGBs so color could be changed and brightness adapted. Maybe I’ll add a clock. I’ve not started yet because I still do not have a HMI concept: I was thinking about tipping on the light, but with all the audio, LED etc functions you can not use tipping. Then I was thinking about tough control. Yesterday I read an article about voice recognition which ws implemented on Arduino…. hmm. Let’s see where this leads me.


Last friday I bought an Arduino. I did not know much about this thing, I ran across it when I visited some possible schools for our son. Some of the pupils showed what they did with it. And there were some really cool projects.

So I decided to buy one and find out where it will need me. I bought a Arduino Starter Kit which comes with multiple components like resistors, LEDs, switches and and and. But the most important thing ist the Project Book with 15 fun projects. The book really starts at the basics and leads you into the world of electronics and programming. Like!

It was at project 3 when I decided that the book is not enough. I needed a more sophisticated project in which I can include my son. So I decided to build robot car!

But with my current level of skills I will to be able to finish this project successfully. That’s why I will divide my project into several minor projects. First starting with a Bluetooth controlled LED. Let’s see where this leads…

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