Karhu Active Pulse teardown

Karhu Active Pulse (W311) was a fitness tracker product that was sold cheaply few years ago. It was quite comfortable on the wrist the UFit application running on Android was just fine (not very good or bad). Most functions go on by pressing that white circle (pulse, sleep monitoring) for about three seconds. You can

Lutron LCR-9063

I bought a Lutron LCR-9063 meter long time ago (expect around 20 years or more) to be able to measure value of coils and capacitors. I has worked well for me. What looks like the same meter are sold as VOLTCRAFT LCR-9063 Component tester. This meter is designed for measuring resistance, inductance and capacitance. LCR-9063

Behringer CT100 look inside

Behringer Cable Tester CT100 is a pretty nice and cheap cable tester for all kinds of audio cables.The CT100 accepts many type of cable you might use in a recording or live performance situation: XLR, mono and TRS phone (¼”, 1⁄8″, TT), RCA and even MIDI. here are three operating modes: Cable Test, installed Cable

Antenna isolator teardown

A ground loop in your AV system caused by antenna connection or TV cable is very common if you have your computer connected to the same system. This type of ground loop problem can be solved by using suitable isolator between your AV system and the antenna cable. Antenna isolator is very convient way to

Moxa Nport teardown

Moxa NPort® 5400 device servers provide many useful features for serial-to-Ethernet applications, including an independent operation mode for each serial port, user-friendly LCD panel for easy installation, dual DC power inputs, and adjustable termination and pull high/low resistors. NPort® 5400 device servers can connect up to four serial devices to an Ethernet network, allowing you

DMX 512 control board DMX 192 repair

DMX stands for Digital Multiplex DMX512 (Digital Multiplex) is a standard for digital communication networks that are commonly used to control stage lighting and effects. DMX can now be used to control almost anything, reflecting its popularity in theatres and venues. I have some DMX-512 controlled lights and also built some DMX-512 hardware myself. I

PIR sensor teardown

This is a tear-down of an interesting PIR (passive infra red) sensor found from some unknown light system believed to be powered from 230V AC. The chips used seem to be ST LM2904 low power opamp and TFK U2100 timer control chip. The sensors are PIR sensor and LDR. The most interesting part is that

Night light teardown

Here is a teardown of cheap mains powered LED night light from LIDL. After few years of use this light became very dim and so useless. I opened it to see what is in it and what was broken. Let’s open it. Circuit board details Here is the circuit diagram. This is quite typical transformerless