Exploring Eagle CAD ULPs #4 – Renumber The Parts Number In Order

Tools for the Electronics Hobbyist Part 2- LC200A L/C Meter

When I started to deal with Chinese electronics suppliers from websites like Alibaba, Aliexpress and Taobao, I discovered that there are huge amount of undiscovered tools from the Chinese market. They are not easily discovered, maybe due to the Chinese language barrier, especially when we deal with a Chinese website like Taobao or maybe because most of us are used to deal with known electronics distributors like Sparkfun.

I also discovered that I can get my stuff from there in a lower price and in most cases of the same quality.
We can’t deny that dealing with known and trusted electronics stores such as Sparkfun and Adafruit is more comfortable and safe, but our proposal is an alternative one.

That doesn’t mean that our series will focus only on tools from Chinese suppliers. We will also explore special tools from Ebay, Tindie and other resources.

This series is weekly, so stay tuned! Please note that when we talk about a tool from a certain store or a supplier, we don’t claim that we guarantee the quality and if the store is trustworthy.

You can reach the posts published in this series using the following link.


Welcome to the second post in this series. Last time we talked about the graphic component tester. This time we are going to talk about another useful tool in our labs. I discovered it from the Chinese vendors and it’s called ‘LC200A L/C Meter’. It’s a tool that measures capacitance and inductance.


It has two leads that are connected to the target inductor or capacitor. LC200A has four measuring range positions:

  1. C range – Capacitance (0.01pF-10uF).
  2. L range – Inductance (0.001uH-100mH).
  3. Hi.L range – Big inductance (0.001mH-100H).
  4. Hi.C range -Big capacitance (1uF-100mF).

This device has three options to power it, through mini USB, 5.5mm DC socket or 4 AA batteries.



The results of the measurements are shown on a 16*2 LCD.


To use it, you need to press the red button for 1 second after connecting the probes so the device calibrates, because the probes may give some drift (error) in the readings. You also need to select the range before connecting the probes with the target capacitor or inductor. You can read more details and features for this device from the user manual. You can also watch the video below, which is a review and a teardown for LC200A.

You can get LC200A for about 40$ from ebay, Aliexpress or Taobao.

Omnipod wearable insulin pump teardown

mikeselectricstuff @ youtube.com shares his wearable insulin tear-down. This is an interesting device to tear-down so take a look.

Omnipod wearable insulin pump teardown – [Link]

DIY Altimeter using a NEO UBLOX GPS module and a Color OLED

In this video educ8s.tv is going to build a DIY Altimeter using the UBLOX NEO-6M GPS module along with a color OLED display with the SSD1331 driver.

About a year ago, I built some GPS projects using this GPS shield. This shield is great but unfortunately it is no longer available for sale. Also its size is big so it is not ideal for smaller projects. So, while searching on Banggood.com I discovered this tiny GPS module. It costs around $16 and Banggood.com was kind enough to send me a sample unit in order to test it

DIY Altimeter using a NEO UBLOX GPS module and a Color OLED – [Link]

Measuring the speed of light with electronics

The speed of light in vacuum is a well-known universal constant and is considered to be the nature’s ultimate speed limit. No matter, energy, and information can travel faster than this speed. The speed of light has always been a topic of great interest and significance throughout history. In the course of measuring the speed of light, scientists have explored numerous ingenious approaches from analyzing the motion of heavenly bodies to artificial quantitative measurements in the laboratory. Michael Gallant describes a very simple approach of measuring this physical constant using an infrared LED, a photodiode circuit, and an oscilloscope. The premise of this method is to allow an infrared beam to travel different distances and then compute the time delay (Δt) between them using the oscilloscope. By measuring the difference in the distances (Δd), the speed of light can be calculated as the ratio of Δd and Δt.

IR Light source
IR Light source

The following diagram describes the setup he used. A Vishay 870 nm IR LED (TSFF5210) generates an IR pulse beam that splits into two beams (L1a and L0) through a beamsplitter (BS). L0 is directly focused onto the photodiode (Pd) using a lens. The L1a beam gets reflected off a mirror, travels along the path L1b, and then focused using a different lens onto the same photodiode. You can see the net path difference between the two beams before they hit the photodiode is (L1a+L1b – L0). If the original IR pulse is kept adequately short, the two optical pulses detected by the photodiode will not overlap in time. An oscilloscope of sufficient bandwidth can therefore reveal the time difference between the two pulses. The photodetector used in this setup was Vishay BPV10 high speed Si pin type with a bandwidth of 200 MHz. The photodiode signal is amplified using an AD8001 Opamp based preamplifier circuit with a gain of 35 (31 dB) and BW of 50 MHz.

Experimental setup for measuring the speed of light
Experimental setup for measuring the speed of light

Michael measured the path difference of the two beams to be 1851 cm and the difference in the time of flight to be 62 nanoseconds from the oscilloscope. This results in the measured speed of light to be 298548387 m/s, which is remarkably accurate for such a simple setup.

Time difference between the arrival of the two pulses can be seen on the oscilloscope
Time difference between the arrival of the two pulses can be seen on the oscilloscope

Find more about this project.

Inductive Proximity Switch Using TCA505


This circuit is used to design an inductive proximity switch. The resonant circuit of the LC oscillator is implemented with an open half-pot ferrite and capacitance in parallel (pin LC) and if a metallic target is moved close to the open side of half pot ferrite, energy is drawn from resonant circuit and the amplitude of the oscillation is reduced accordingly. This change in amplitude is transmitted to a threshold switch by means of demodulator and triggers the outputs.

Inductive Proximity Switch Using TCA505 [Link]

LTC3623 – Switching regulator doubles as Class-D audio amplifier


Clemens Valens @ elektormagazine.com discuss about LTC3623 switching regulator which can be used as Class-D Audio Amplifier.

Sure thing, Elektor has published several designs of adjustable power supplies based on switching regulators, so we know that doing this properly in a reproducible way and without making things overly complex requires some serious head scratching. The anxiety may be reduced vastly though by a new adjustable synchronous buck regulator which uses a single resistor to set its output voltage anywhere between 0 and 14.5 volts. Using the device is very simple; you can even use it as an audio amplifier.

LTC3623 – Switching regulator doubles as Class-D audio amplifier – [Link]

Chronio – Low power Arduino based (smart)watch


Max.K @ hackaday.io designed his own impressive watch based on Atmega328p with Arduino bootloader, Maxim DS3231 (<2min per year deviation),  96×96 pixel Sharp Memory LCD (LS013B4DN04) and it’s powered by a CR2025 160mAh coin cell battery.

Chronio is an Arduino-based 3D-printed Watch. By not including fancy Wifi and BLE connectivity, it gets several months of run time out of a 160mAh button cell. The display is an always-on 96×96 pixel Sharp Memory LCD. If telling the time is not enough, you can play a simplified version of Flappy Bird on it.

Chronio – Low power Arduino based (smart)watch – [Link]


16×32 RGB Matrix Panel Driver Arduino Shield


Raj @ embedded-lab.com has revised his RGB Matrix Display Shield to an improved version.

The shield now also carries the DS1307 RTC chip on board along with a CR1220 coin cell battery holder on the back. It is applicable for driving popular 16×32 RGB matrix panels with HUB75 (8×2 IDC) connectors. Row and column driver circuits are already built on the back side of these matrix panel. The data and control signal pins for driving rows and columns are accessible through the HUB75 connector. It requires 12 digital I/O pins of Arduino Uno for full color control.

16×32 RGB Matrix Panel Driver Arduino Shield – [Link]

Test application for the FPGA Tibbit in the smart LED controller configuration

This application example shows how to connect and use RGBW LED stripe with TPS hardware platform. The main difficulty is that LEDs have their own color generation circuit inside. New FPGA Tibbit #57 can generate fast PWM signal, which is needed for proper LEDs operation. Also, the topic shows the main advantage of FPGA technology. It allows the user to create any external interface, which will be easily connected to the TPS platform.

Test application for the FPGA Tibbit in the smart LED controller configuration – [Link]