In this lesson we show how to detect light levels with a Raspberry Pi and a photoresistor. The photoresistor is connected in a voltage divider to the ADC0834 AD converter, which then connects to the Raspberry Pi. The schematic of the circuit is below:
In this video lesson we show how to create a programmable temperature alarm using the Raspberry Pi, the DHT11 sensor, the ADC0834, a potentiometer and a buzzer. The results are displayed on a LCD1602 LCD display with a i2c connection. The device operates in either program mode or monitor mode. Pressing the button puts you in programming mode. In this mode you turn the potentiometer until your desired set temperature is reached. Then pressing the button again will switch you to monitor mode. In monitor mode the current temperature and humidity are displayed on the LCD. When the temperature exceeds your setpoint, the buzzer will release an audible alarm. Below is the schematic for our build.
In this lesson we learn to make a streaming IP camera with a Raspberry Pi Zero W, and Raspberry Pi camera. The Pi will create a RTP stream, which can then be read by a Jetson Nano on the same network. We use OpenCV to read the frames on the NVIDIA Jetson Nano side.
This is the command to launch the Raspberry Pi camera, and start the RTP stream. This command works well for the Raspberry Pi Camera, version 1.
1 | raspivid -t 0 -w 1296 -h 730 -fps 30 -b 2000000 -awb auto -n -o - | gst-launch-1.0 -v fdsrc ! h264parse ! rtph264pay config-interval=1 pt=96 ! gdppay ! tcpserversink host=0.0.0.0 port=8554 |
For the Version 2 Camera, I recommend:
1 | raspivid -t 0 -w 1280 -h 720 -fps 30 -b 2000000 -awb auto -n -o - | gst-launch-1.0 -v fdsrc ! h264parse ! rtph264pay config-interval=1 pt=96 ! gdppay ! tcpserversink host=0.0.0.0 port=8554 |
This is the Gstreamer code on the Jetson Nano side to grab the RTP Frames. On host= below, be sure to use the IP address of your Raspberry Pi.
1 | camSet2=' tcpclientsrc host=10.1.37.28 port=8554 ! gdpdepay ! rtph264depay ! h264parse ! nvv4l2decoder ! nvvidconv flip-method='+str(flip)+' ! video/x-raw,format=BGRx ! videoconvert ! video/x-raw, width='+str(dispW)+', height='+str(dispH)+',format=BGR ! appsink drop=true sync=false ' |
There is a lot happening in the Maker Space! We have just watched two new major releases of embedded microprocessor platforms . . . the Raspberry Pi Zero Model W and the Onion Omega 2+. Both these platforms are impressive in that they both offer a small package with onboard WiFi for $10. This combination of features, price and size opens up a new world of possibilities for compact, portable projects.
After reviewing both of these platforms, we choose the Raspberry Pi Zero model W as the platform we will be pursuing at this point. The video above gives a head to head comparison of the two platforms, and the rational behind our decision.
We are very excited to see that Raspberry Pi has announced the release of the WiFi model of the Raspberry Pi zero, which has onboard Bluetooth and WiFi. Anticipated price is $10. We believe this new model will be a game changer, and will accelerate the development of exciting new prototypes and products. As of this morning, I have not found any supplier with the devices in stock, but will order one as soon as I can find a supplier. I plan to do some tutorials and projects as soon as I can get my hands on one of these. Please share your thougts below.