sdgprofileSteve Gardner is an Electronics and Firmware Engineer in the UK. He works at an engineering design consultancy where he primarily architects electronic medical devices. His focus is on analogue and power electronics although most design work involves the use of microcontrollers, processors or FPGAs which he is proficient with.

In early 2015, Steve decided to start publishing regular content on his YouTube Channel to share some of his knowledge and personal projects, which he hopes to grow both to engage others in the hobby and also to help complete stalled projects…

Steve started electronics as a hobby as early as he can remember and has always had a fascination with learning how electronic devices work. He has had a full time electronics job for the past 15 years designing a multitude of electronics devices from pregnancy testers to precision surgical cutting tools.

An interesting RGB LED controller

Just spotted this neat looking RGB touch controller for RGB LED strips etc. It looks to fit in a standard 25mm 1 gang pattress so might be handy for any permanent RGB installations in your home:

Take a look on the Banggood website

Since receiving these controllers, I decided to design my own PCB so that it could control DMX Lights. The first step was reverse engineering the connectivity between the touch panel and the controller IC.

Now some finishing touches with a new PCB from JLCPCB.

The production files for ordering your own PCBs from JLCPCB can be found here:

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The Effect of DC Bias on MLCC Capacitors

This video explores the effect of DC Bias on Class II MLCC Capacitors and why once you’ve deployed a ceramic capacitor in your circuit, the capacitance may not be the same as the specified value.

SDGEE #066 – MLCC Capacitors
MLCC Schematic
Schematic for the Capacitor Tester

Above is the schematic for the test PCB. The parts listed are only suggestions and not particularly critical. You may want to select a Zero-drift chopper stabilised op-amp for U2 to give the best results. (I used LM7321 for U1 and AD8628ARTZ for U2).

The PCB should be powered from 5V, and once you have a capacitor soldered down, adjust RV1 so that the output is at 1V precisely. As you apply a bias voltage at J1, you will see the effect of bias voltage on the capacitor.

Since the output is calibrated at the start of the test to 1V and the output is proportional to capacitance, you can simply multiply the nominal capacitor value by the output voltage to work out what the actual capacitance is at your test voltage.

Change in capacitance for Y5V Capacitors
Change in capacitance for X7R Capacitors
Change in capacitance for other types of dielectric

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Best BST-933B/Jabe UD-1200 Soldering Station

Here we have a nice high power soldering station for those that want something a little more professional for their electronics work. It’s essentially the same as the popular JBC soldering station but at around half the price.

The unit I obtained from Banggood unfortunately had the Chinese UI, but there is a seller on AliExpress selling the Jabe branded station with an English UI. The Jabe and Best stations are idential. Product – Jabe UD-1200 Precision Smart Lead-free Soldering Station 2.5S Rapid Heating with Dual Channel Power Supply Heating System

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A DIY SMD Pick and Place Tool for Electronics Assembly

This video describes a DIY Vacuum Pick-up tool for picking and placing parts from an SMD component tape. The basic design for this tool involves using a vacuum pump and a solenoid to control the vacuum to a handpiece under control of a foot pedal.

By applying vacuum to the tool, a component can be picked up from an SMD tape and transferred to the PCB being assembled. The schematic, Gerber files and firmware for the PIC18F13K22 microcontroller are attached below.

Schematic of the Design

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Hayear HY-2307 Camera

A look at a 16MP CMOS Camera that can record direct to SD Card, output to HDMI and also USB interface.

This one is from Banggood:
And is coupled with a 180x Lens is from Lapsun on eBay:

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