Archive for the ‘Raspberry Pi’ Category.

Raspberry Pi breakout board with ESD, PoE and Cortex M0

This is Raspberry Pi GPIO connector breakout board with some additional features:

  • “Real” or “passive” PoE with 12V output
  • 5V DC/DC module
  • Additional 3,3V regulator
  • ESD protection on all GPIO pins
  • two additional pins for each pin on R.Pi 40 pin GPIO connector
  • Separate UART and I2C headers
  • 3,3V Supply for periphery is selectable: from R.Pi or from external regulator
  • STM32F070 or similar in TSSOP-20 housing for controlling additional sensor or any other hardware
  • Jumper for Cortex-M0 / R.Pi UART connection

First prototype

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Simple Rh, T and p sensor with UART communication

The Pressure, temperature and humidity sensor based on MS5637 HDC1080 originally (Rev. 2) operates via RS485 interface and multidrop HDLC-like protocol.  I decided to simplify this for use with Raspberry Pi, arduion or any other mass platforms. First, I took away the RS485 transceiver and second, I simplified the communication.

First adaptation was easy:

Remove RS485 driver and connect Rx/Tx to A/B

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Tiltable housing for Raspberry pi camera

The second version (here is larger 1st version with fixed angle) of R.Pi camera housing is smaller with 9 LEDs and possibility to adjust camera angle.

Adjustable housing with 9 LEDS for IR illumination

The 3D models are available on 3DcontentCentral or in GrabCad.

STL for 3D printing is on Thingiverse.


Raspberry pi camera housing

This is housing for R.Pi camera V2 with LED illumination.

Camera housing

It is 3D printable housing and PCB with 9 IR LEDs with enable.

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Call URL with keypress on Raspberry Pi

Here is scenario:

pushbutton is connected to Raspberry Pi GPIO pin. Whet button is pressed, R.pi calls remote URL.

This can be useful for many simple applications, like detecting and timestamping passes at certain location.

The R.pi should be up and running. Connect the pushbutton to free GPIO. In our example we connected the button to pin 11. The pin is configured with the pullup, which means the button must pull the GPIO pin to ground. Pin 12 on r.Pi model 2B (40 pin P1) is GND:

Ultra simple schematic for this example

Now prepare some simple script on your fancy web browser, which will be called when someone presses the button. Here is example, which simply adds one line with time and date at the end of the file “log.txt” every time when file is loaded:

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Raspberry Pi “folded” USB connector

The R.Pi is excellent module for many applications. Unfortunately it is not easy to stack USB modules connected to it. When USB module, e.g. RTL-SDR is attached to the R.Pi, the whole package become very long requiring larger box. One solution is to use USB extension cable, but it again require additional space. Here is another, more compact solution:

  1. remove the USB connector from your module
  2. place SIL header at the pins for USB connector
  3. connect the USB module back “folded around the corner”

usbvinkel1 usbvinkel2 usbvinkel3

Simple 5 minutes housing for Raspberry Pi with Camera

I took old cover from plastic sewer pipe (it was never used ha ha). Then I drilled four holes for M3 screws and one bigger hole for camera module lens. The housing was prepared from one litre PET bottle. I cut the bottle to proper size and inserted raspberry Pi with the camera inside the bottle. Next the LAN cable with passive 5V “PoE” was inserted.

Finally, I heated the bottle with hot air gun at the camera side to shrink a little bit and tightly close the gap between the plastic camera “holder” and the bottle .

Photos below will tell more than thousand words:

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Add weather report from local weather station to APRS node

I recently set up a APRS gateway. Check instructions in older posts. In the script pymultimonaprs you can set weather when set in a json-file. eg: “weather”: “/path/to/weather.json”. I live next to the automated weather station for our city. Instead of building own WX I decided to use the data from this nearby station. The data is provided in XML from our national agency ARSO. The data is available for some major cities in Europe, too.

Main idea was to prepare PHP script to parse the XML data and prepare text file, which is acceptable for pymultimonaprs. Next step is to wget this text from some server and copy it to the raspberry pi with cron job.

This page will give you an example how to:

  • parse XML file with weather data using PHP script
  • output the text for pymultimonaprs weather file
  • prepare cron job with raspberry pi



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Raspberry Pi + RTL SDR dongle = APRS Rx only gate (Part Two – Decoder)

This is part two (here is part one) of the tutorial how to use Raspberry-Pi in APRS gateway.


In part one I explain how to install OS for Raspberry Pi and get RTL dongle up and running, which enables radio reception and listening received signal with FM demodulator on audio jack (simple FM receiver).  For next steps you will need HAM licence with own call sign. Mine is S54MTB.

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Raspberry Pi + RTL SDR dongle = APRS Rx only gate (Part one – FM Radio)



I have couple of raspberry pi’s laying around doing nothing useful. I decided it’s time to use it better than dust collectors. This tutorial is placed here for reference for any OM who would like to setup APRS Rx only node based on R.pi. Here’s what you’ll need (hardware):

… and software:

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