Wireless Chat using NRF24L01+ 2.4GHz RF Transceiver on Arduino & Raspberry Pi Ubuntu Linux

After a bit of success implementing an Arduino 2.4GHz Transceiver , I was encouraged to explore a more familiar environment, something with Python and Linux in the mix. After a short period of research I landed on the circuitpython-nrf24l01 pypi project page, and quickly began digging through their examples . It wasn’t long after I had a working prototype that mirrored my Arduino code quite closely: Components CanaKit Raspberry Pi Zero W (Wireless) Complete Starter Kit - 16 GB Edition RF24L01+ 2.

Wireless Chat using Arduino & NRF24L01+ 2.4GHz RF Transceiver

It has been quite some time since I’ve tinkered with an Arduino, and this go around I decided to learn something new. The [NRF24L01](http://amzn.to/3iFalxX(opens in a new tab)) 2.4GHz Transceiver is an extremely affordable wireless chip, I managed to pickup 10 units for around $12. This chip allows sending and receiving on the 2.4GHz wireless band . Lucky for us there is a great Arduino library just waiting to be imported, thanks maniacbug !

Remote Controlled Car using Raspberry Pi and Webcam

Setup First thing I tackled was setting up the L293D H-Bridge on the Bread Board. I found myself referencing the following Diagram a couple times. Step one is connecting your chip down the center of your board: From here I connected the 3 power pins to my board’s power rail using a few Jumpers : A few more Jumpers connect each side of the chip to ground: Finally I use a couple Wires to connect both sides of my power and ground rails:

Arduino values to Python over Serial

I’ve done a little bit of reading on the ReadAnalogVoltage of Arduino’s home page, and they give a straight forward way to read voltage from an analog pin. I wanted to take this one step further and send the value over serial, then read it in Python using pySerial . My setup is very straight forward, I have a Arduino UNO , a bread board, and a battery pack holding 4x AA batteries: To start out I want to merely print the voltage value in Arduino Studio to the serial console, my code looks something like this:

SensorTag data merged with Open Weather Maps

About a week ago I worked on SensorTag metrics with Grafana . This week had some interesting weather today here in Austin, and I wanted to see to visualize it as well. Luckily Open Weather Maps offers a free API for gather near real-time weather data based on city code. def __get_open_weather_data(): url_path = 'http://api.openweathermap.org/data/2.5/weather' api_key = '??????????' url = '%s?zip=73301&APPID=%s' res = requests.get(url % (url_path, api_key)) if res: if res.

Arduino meet Raspberry Pi

While at the electronics store the other day, I noticed they had motion detectors on sale for only $4. I decided with my latest obsession of electronic tinkering, picking up a OSEEP Passive Infrared Sensor (PIR) Module might be fun. I guess I should have done a little more reading on the packaging; by the time I was home, I noticed this sensor reported in analog , not digital. This was an issue as the Raspberry Pi only reads digital input.

Raspberry Pi and Official NFL Score Board API

Now that I’ve got my hands on a Raspberry Pi 3 Model B Motherboard , I decided nows a good time to play around with the 16x2 LCD Module Controller HD44780 I had laying around (I’ve had this thing since December 2015). A live NFL (National Football League) score board seemed fitting as the season just started. I found a really good write up on raspberrypi-spy.co.uk about wiring up the controller and Pi, here is the diagram I used:

SensorTag Temperature Readings in Python

I wanted to wrap up my previous post (TI SensorTag Temperature Readings ) with a little python example, thus this write is going to be short and sweet. Using the bluepy python library (written by Ian Harvey) I’ve been able to to capture temperature readings, then covert them to Fahrenheit. To demonstrate I captured a couple temperature samples, a few while sitting on my desk, and a few held up to my air condition vent:

MagTek USB Card Reader Hacking 2

So back at it, now with some code to decode the common financial card: Let start out by showing the end results of scanning my Freebirds card: # ./main.py Please swipe your card now: Raw String: %B???????????^FANATIC/FREEBIRDS^4211?;????????????=???????????? Card Holder: FANATIC/FREEBIRDS Card Number: ????-????-????-???? Expiration Date: 11/42 As you can see we still have our raw string, this is being decoded from the code I used last time. However now I have the Card Holder’s name, Card Number, and Expiration date, this format was all outlined quite well on Wikipedia .

MagTek USB Card Reader Hacking

So just the other day I received my MagTek MSR100 in the mail, this unit only cost me about $20 and I have to say I’m very satisfied with it. After opening the box it was delivered in I quickly noticed no documentation was provided. No worries I figured, this will make hacking at it that much more fun. I started out by connecting the USB device to my Gentoo Linux laptop and swiped a card, I noticed on my console prompt the card data was spewed out.