Archive for Tutorial

Tutorial on Programming a Waveshare 7.5-Inch Multi-Color e-Paper Display & Info-Frame

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.

Quest for mm-Wave Capability: Teardown, Analysis & Experiments on Generation & Detection

In this episode Shahriar demonstrates the effort for collecting affordable components and instruments in the past year to be able to generate mm-wave frequencies in the lab. The main goal is to generate synthesized CW signals beyond 26.5GHz and to be able to analyze them on the Keysight MXA Spectrum Analyzer.

Several instruments and components are which include the HP 83752B Synthesized Sweeper, HP 83556A mm-Wave Source Modules between 26.5-40GHz and 40-60GHz using doubler and trippler architectures, HP 8349B 2.0-20GHz amplifier, HP 11970 series harmonic mixers and OML DPL313B diplexer. Combining all these instruments along with various waveguide to coax converters mm-wave generation and detection is successfully demonstrated.

Finally, a full teardown of the mm-wave source module is presented which includes the preamplifier as well the waveguide module with very interesting design architecture.

Tutorial, Experiment & Teardown of a 24GHz Doppler Radar Module

In this episode Shahriar demonstrates a full analysis of a CDM324 24GHz Doppler radar module from IC Station. Opening the module reveals a series of microwave PCB components and several active devices. A complete analysis of the module is presented. The unit is then measured and the impact of antenna impedance and power supply voltage on the output frequency is measured. The phase noise of the output signal is also measured. Using a series of servo motors, the radiation pattern of the antenna array in both azimuth and elevation is also presented.

Using the radar module the speed of a computer fan is remotely measure using an oscilloscope and FFT function.

All proceedings from Patreon for this video will be donated.

Noise & Performance Considerations of the DPH3205 Buck-Boost DC/DC Converter Module

In this episode Shahriar investigates the noise generated from the DPH3205 Buck-Boost DC/DC Converter Module. This module is part of a family of affordable devices which can be purchased online. The particular model (DPH3205) shown in this video can be purchased from here. The Keysight S-Scope in conjunction with the N7020 power probe is used to measure the noise behavior of the circuit. It can be observed that the module produces many harmonics of noise spanning up to and beyond 1MHz.

A power operational amplifier is used in conjunction with a 4V Zener diode to produce a crude voltage follower. The PSRR of the operational amplifier can filter the noise from the DC/DC converter. This is verified by measuring the noise coming from the operational amplifier. The noise is significantly reduced. This circuit is not entirely practical and is used for demonstration purposes only.

Tutorial, Teardown & Experiments with Stanford Research SR530 Lock-in Amplifier

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.

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