WiFi enabled Motors


WiFi controllable motors for your many projects. An Open Source platform that anyone can use.

Using our motors is as simple as joining your motors network (or adding the device to an existing network) and controlling it with any of our apps, its built it webpage, or just raw JSON packets. Our motors are made to be both a solution for someone not skilled enough to set up stepper and servo motors, and for experts who want a less messy way to implement motors. Our hardware and software are both on github, and our board was made specifically to be compatible with the free version of EagleCad.

WiFi enabled Motors – [Link]

Creating footprints in KiCad using a scanner


Jan @ jasiek.me decided to use a flatbed scanner to trace out a footprint in KiCad. [via]

Some time ago I sourced a number of very cheap SD card sockets from China for a hobby project I was working on. Sadly, when it came to PCB design, I couldn’t find the footprints for this particular socket anywhere – the part being a proprietary invention of the factory rather than a cheap knockoff of a reputable brand like Amphenol or Molex for which drawings are readily available off of snapeda.com.

Creating footprints in KiCad using a scanner – [Link]

App note: Engineering scaling


Scaling large values to be fed on limited input digital meters, application note from Murata. [via]

It is oftentimes necessary to attenuate “large” input signals down to a level that more closely matches the input range of a selected meter. For example, suppose the signal to be measured is 19 Volts, and the input voltage range of the available meter is 2 Volts (the preferred model for any attenuation circuit). Obviously, the “raw” input signal voltage is much too high for a ± 2V meter to measure directly and must first be attenuated.

App note: Engineering scaling – [Link]

Improvement in the resolution of Retinal Prostheses

Image : Roux S., Matonti F., Dupont F., Hoffart L., Takerkart S., Picaud S.,
Image : Roux S., Matonti F., Dupont F., Hoffart L., Takerkart S., Picaud S.,

Denis Meyer @ elektormagazine.com discuss how the researchers improved the resolution of retinal prostheses.

A retinal prosthesis substitutes for the photo-receptor cells of the defective retina. It’s composed of a camera carried in spectacles; electronics that processes the camera information; and a matrix of microscopic electrodes implanted in the eye in contact with the retina. These electrical signals are carried to the brain by the optic nerve. With such implants, totally blind patients can recover some visual perception in the form of spots of light called phosphenes. Alas, these are not clear enough to recognize faces, read or move around.

Improvement in the resolution of Retinal Prostheses – [Link]

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]