Author Archives: volker

Checking out Hammock

31 May 17
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I am currently checking out Hammock as a base for Microservices.


Stumbled about

21 May 17
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An alternative to the arduino development environment. Support for different platforms like ESP8266, ESP32, AVR…..

Good support for including libraries.

Start to love it. Based on the Atom Editor (Well, not my primary choice of editor because its too slow, but for that environment fine)

check it out here…

Alternatives to Owncloud

14 May 17
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Currently checking out on alternatives to owncloud… tried cozy… hmmm nice but not too much more functionality to owncloud

Server Update

12 May 17
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Updated this server to 24GB (actually Hetzner did, I just payed).

Additionally updatged wordpress, owncloud, gitlab

Clock with Timer

03 Jan 17
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Another little project is this one:


An LED Clock driven by an ESP8266, using those 8×8 LED Matrix components:

In principle very easy. The ESP is programmed with Arduino, using a NTP Library and a Library for the Matrix LEDs. The only tricky part was to reprogram the Matrix Library because each of the 8×8 matrix elemens was turned by 90 degrees, so I had to programmatically turn them back. Otherwise I had to resolder all of the 8×8 components (too lazy for that).

Besides having a nice clock now I also implemented it to be controllable via UDP commands. So far 2 functions are implemented:

Clock and Timer. I also implemented a little App for those functions



We have settings to specify the IP and port of the clock. 4 Buttons determine the functionality of the clock:

Set Timer => Set the timer to a given value (hour, minutes, seconds). After it is set the clock shows the timer counting down.

Cancel Timer => Already indicates that this resets the timer and displays the clock.

Show Time => While the timer is still counting down, the current time can be displayed.

Show Timer => If you decided to display the time instead of the timer, this brings you back to display the current timer value.


ESP32 arrived

03 Jan 17
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I am an absolut fan of the ESP8266 in its various forms. It is really cool to build things with it. A device with Wifi, several IO Pins and programmable via C or Arduino is a perfect match for small devices.

The biggest drawback of such a device is: In order for the Wifi to work, you need to connect it to a Wifi Network. In most cases this is the one of your home. So you provide the code with your WIFI SID and passphrase (hardcoded).

If you want to use the device in another WiFi network it needs to be reprogrammed. This is not really portable. Bluetooth for controlling devices is suited way better. You pair the device, then you communicate with it. Bingo.

Espressif must have noticed or they just took the next logical evolutionary step of the their 8266 and created the ESP32. It is more powerful, has more IO lines and bluetooth.

It was long announced. Now you can buy it. So did I. thanx to Watterott I ordered and got 5 of them. Now I am looking for some projects to fit.


RS232 / Bluetooth Adapter

30 Dec 16
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This is the first prototype of a RS232 / Bluetooth adapter. Its design is quite simple:

Use a standard MAX232 circuit and connect the ttl out/inputs with an HC05/06 bluetooth transceiver.

Although some MAX232 seem to work with 3,3V I had bad experiences with it so I drive the MAX with 5V and the HC05/06 with 3,3V.

2 bridge diodes reduce the 5V to about 3,3V to power the HC05/06. A level shifter transforms the TTL signals between 5V and 3,3V. MAX would understand 3,3V, but the HC05/06 most likely will sooner or later die from the 5V.

In this picture of the prototype the level shifter is missing.

Since the RS232 does not have a power pin, the 5V have to come from somewhere else. Usually there is a USB connector around => take it from there (see the grey little cable go away from the board, thats the link to the USB power).



Then I bought this in the internet.


I had a lot of touble with it. No manual available so I had to search the whole internet for info about it. First I attached a Mini USB to power it, easy. A red LED indicated operation and a blinking blue LED indicated the will to pair.

Pairing was also not really hard to do. Device could easily be found and be paired with my mobile and a tablet.

Then the trouble started. The BT connection was lost latest after 2 minutes. All the time. It drove me crazy. As experiment I unpluged the USB power and used the BAT connector to provide it with 5V. Wow. No connection losses anymore.

Next I had to find out how to increase the default of 9600 Baud. In order to do so it is as it is with all HC06: Connect a TTL Terminal to the HC06. For that there are four PCB Pads you have to provide a 4pin hreader row ( you can see it in the picture between the HC and the switch).

After the Baud change was done the real life test with a RS232 device had to be made. That is where I currently am. In principle it works, but even with 115200 Baud it is slow and has lags. I had this effect with other HC05 “compatible” transceivers as well. Well, I will hang on to that.

Would I buy it again? No ! I am thinking about getting my prototype to a PCB and make 4-5 of it.

What do you need RS232 interfaces anyway? Good question: MY purpose for them is to control Measurement devices (like from “Rigol”).

App for devices of the company of Rigol

30 Dec 16
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I am currently developing an App for Rigol Devices. The App (Android) will be able to control Rigol devices via Lan or Bluetooth.

For Bluetooth an RS232/Bluetooth adapter is necessary.

First Version of Bluetooth controllable Light Bulb finished

15 Nov 16
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I just finished work on the prototype of a Bluetooth controllable Light Bulb. A big One (25 cm diameter)


LED Mobile

18 Oct 16
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I started working on my new LED Mobile project.