In this episode Shahriar demonstrates the capabilities of a Waveshare 7.5-Inch tricolor e-Paper display. By combining the display with a Raspberry Pi Zero, the SPI interface of the mini-computer can be used to program and configure the e-Paper display using Python scripts. Furthermore, the Python script takes advantage of the available API of a few website to provide relevant information such as the current date, calendar, task list with due-dates as well as the current weather and weather forecast all in a clean user interface.
The complete Python code is presented and analyzed and the principle operation of the display is also presented. Do not forget to check Applied Science’s video on this topic as well. Finally, the individual pixels are examined under the microscope while the screen undergoes a refresh which demonstrated how various colors are displayed.
The complete code can be downloaded here. You can also buy the e-Paper display here and the Raspberry Pi Zero kit here. If you are interested in using an ESP WiFi module with Arduino to interface with the e-Paper display, it can be found here. You can chose any picture frame to complete the project. The Task Manager and Weather APIs can be found here and here.
In this episode Shahriar goes over the operation and principle theory behind Lock-in Amplifiers. The SRS SR530 is one of the most iconic lock-in amplifiers ever made and since it offers two channels it can be used to perform very interesting experiments across many domains. After reviewing the block diagram and equations governing the theory of operation, a brief instrument teardown is presented.
Two unique and interesting experiments are also presented. In the first experiment the instrument is used to measure the speed of light. This is accomplished by measuring the wavelength of sound at 20kHz using a pair of speakers and a function generator. The distance between the speakers can be carefully adjusted and the relative signal strength from each lock-in channel is measured and thus the wavelength can also be measured.
In the second experiment the sensitivity of a red LED to blue laser light is measured. Due to the semiconductor composition of the red LED as well as its red plastic casing, the responsibility of the LED to blue light is extremely low. A chopper is therefore used to lock the light to the lock-in amplifier’s reference input. The measured induced current is measured down to very low optical level in the order of hundreds of fempto (10^-15) amps.
In this short episode Shahriar demonstrates an overview of the new Tektronix MSO58 8-Channel 6.25GS/s 2GHz Mixed-Signal Oscilloscope with up to 64-Bits of digital channels. The scope features independent ADC, data acquisition and memory per channel as well as FlexChannel architecture which allows each channel to act as either a 2GHz analog channel or an 8-Bit digital channel. The scope also features a brand new GUI interface on an HD 15.6″ display with significant performance enhancement and touch interface optimizations. A full review of the instrument will be provided in the future.
In this short episode Shahriar shows a few items to give away! Please leave a comment and a person at random will be chosen. There will also be a Q/A session sometime in the future, please also leave your questions in the comment section.
The winners of the draw will be notified at a later date.
The Signal Path (TSP) is an electrical engineering video blog for industry professionals, students and hobbyists. TSP is a non-for-profit website dedicated to provide free education spanning a wide range of electrical engineering topics. Equipment reviews, tutorials and repair videos are posted regularly.