Banking API

For another project (the shackbureau) we needed to convert banking numbers from the old German system to the European system. At first we used the webpage of a German bank but after their relaunch the form was removed.

After some searching we found the data from the German federal bank as an XLS file. But XLS is a bad api to use from another site. The solution is the banking-api:

Some usage examples:

  1. Search for a banking number (old German system):

  2. Search for a banking number based on the new system:

  3. Search for all banks in Berlin:

  4. Search for all banks with zipcode 10117:

  5. Generate the iban based on old German account data:

    For example:

    curl --request POST --url --header 'Content-Type: application/json' --data '{"country": "DE", "blz": "64090100", "account_number": "1234567"}'



The sourcecode of the API is on github:

Particles sensor of opendata-stuttgart


  1. drill two holes for the sensor and 2 to 4 for the nodemcu
plastic tube image
  1. assemble ppd42ns with cable fixer to tube
  2. the same for nodemcu.
  3. Connect pins of PPD42NS to nodemcu
  • PPD42NS Pin 1 (grey or green) => GND
  • PPD42NS Pin 2 (green or white)) => Pin D5 / GPIO14
  • PPD42NS Pin 3 (black or yellow) => Vin
  • PPD42NS Pin 4 (white or black) => Pin D6 / GPIO12
  • PPD42NS Pin 5 (red) => unused
  1. final version
final tube image


German version:

  1. Download Arduino software (tested is version 1.6.5):
  2. Add esp8266 boards to Arduino software:
  3. We have more than one working version of the firmware. For example
  4. Change wifi settings if no Freifunk is available.
  5. Upload software to nodemcu

Register sensor on API

  1. Watch serial console to see chipid
  2. Send chipid to one of the admins of For example me.
  3. Describe in the email the location you apply the sensor to. Should be outdoor!

Shinyei PPD42NS dust sensor

Stuttgart, the city I live in, is on first place for most particles in the city. But there is only one sensor in the city to measure the particles.

As OK Lab Stuttgart we want to get open data from the city or aquire our own data. In this case we want more data points for particles. And not only at one position in the city, but on as many as possible.

We decided to try the PPD42NS. Other projects used the PPD42NS before:

The datasheet of the PPD42NS from the shinyei website: And some kind of deconstruction how the sensor works:

There are a few examples how the sensor is used with Arduino, i.e. or

The arduino is not cheap enough to build lots of them and distribute them. And wifi is missing (or too expensive). So we decided to try the ESP8266 which is widely used in the hacker community at the moment.

Our sourcecode is at But this is work in progress. The esp8266 is a lot faster than an arduino, so we have problems with very short peaks in the digital output of the sensor and need to smooth the signal. To illustrate the problem we made a few pictures with a digital oscilloscope:

ppd42ns oszilloscope imageppd42ns oszilloscope imageppd42ns oszilloscope imageppd42ns oszilloscope imageppd42ns oszilloscope image