Product tests

DMX-512 led light teardown

Here is a tear-down of a very cheap DMX-512 controlled LED light from It promised four colors (R, G, B and white) with 15W power and DMX-52 controlling. It has some reliability issues so I decided to take a look inside. Here are some pics of the product first. What is inside? Opening few

2in1 Wireless and Wired Microphone

I got a very cheap wired/wireless mic  from I plan was to have a cheap “disposable” microphone for uses where I don’t want risking the more expensive microphone. Basically the product looks OK. The construction is plastic, but till feels acceptable for the price (less than 10 Euros on sale). If I get this

Testing NanoVNA

NanoVNA is very tiny handheld Vector Network Analyzer (VNA). A vector network analyzer (VNA) is an instrument that can be used to measure antenna or coax parameters such as SWR, impedance and loss. It can also be used to characterize and tune filters. It is a very useful tool to have if you are building

Micro Bit case

The Micro Bit is an open source hardware ARM-based embedded system designed by the BBC for use in computer education for use in UK. It’s use has spread to many other countries as well. It is a quite nice Bluetooth IoT experimenting platform with low barrier of entry to programming. I have few years ago

Component tester case

I had earlier built Original Hiland DIY M12864 Graphics Version LCR ESR PWM Transistor Tester Kit and used it successfully. The kit worked well, but on longer term use I felt that the lack of proper case for it was sometimes annoying. I had some time though if making my own case, but it felt

Mustool MT77 multimeter

I saw one day an interesting looking multi-meter MUSTOOL MT77 Large Screen Smart Digital Multimeter Voltage Tester 3-Line Display Fully Auto-Range True RMS 6000 Counts DMM with Analog Bargraph.It is advertised as phone size design: 12 mm thin body and pocket size design make it looks like a smartphone. The meter has unibody design so

Cheap spectrum analyzer and signal generator

In search for some cheap and useful RF test hardware, I came by Geekcreit® Spectrum Analyzer USB LTDZ_35-4400M_Spectrum Signal Source with Tracking Source Module RF Frequency Domain Analysis Tool at sale price of aroundy $30/EURO30. It looked to have quite promising specifications: Attribute: RF frequency domain analysis tool Interface: usb Power supply: usb Standby current:

Socket tester tested

An electrical outlet tester, receptacle tester or socket tester is a device used to verify that an electrical wall outlet is connected correctly. It confirms continuity and polarity of the electrical connections. The outlet tester is designed to check that each contact in the outlet is connected to the proper wire in the building’s wiring.

Useless device kit

A useless machine is a device which has a function but no direct purpose. Typically it is an amusing engineering “hack“, or as an intellectual joke. The most well-known “useless machines” are those inspired by Marvin Minsky‘s design, in which the device’s sole function is to switch itself off by operating its own “off” switch.

USB cable tester

I had a small box full of USB cables that I did not know if they were good or not after use. Those were taken out of use when they did not seem to work OK, and nothing is more annoying than unreliable USB charging cable. I found this 3-In-1 Micro USB Type-C Data Mini