Electronics

A time-delayed alarm is a useful device that can be used in various scenarios, such as security systems or to remind you to close the freezer properly. The alarm is triggered after a certain amount of time has elapsed, providing a delayed response. In this article, we will discuss the design of a time-delayed alarm using two NE555 timer ICs and some passive components. The NE555 timer IC is a popular integrated circuit that can be used in various applications, including timing and oscillation, both will be used in this design.

Jan 3, 2024

I repaired this for my girlfriends mum who wanted to throw it away. DC61 Battery Pack nominal voltage: 21.6 V rated capacity: 2100 mAh (46 Wh) 6-CELL (214141) 6INR19/66-1 Preliminary Testing ✔ PSU 26 VDC at dc barrel plug ❌ No current draw when plugged into battery Unless the button is pressed no voltage is applied at the terminals After pressing the button on top of the battery the light flashes red 32 times and then green once (the 32 flashes of death) before extinguishing and a voltage of 11 VDC was measured at the two battery terminals Disassembly After prying the battery casing open using a metal prying tool, plastic spudgers and plastic picks to keep the released latches open the battery measured 22 VDC at the main battery terminals.

Dec 31, 2023

My friend saved this one from the trashcan. Because it was defective I offered to repair it for her. Defects The filter retainment clip on top is broken. The vacuum works as intended but shuts off after a short time. When pressing the trigger again the vacuum again works for a short duration. The on-time decreases after consecutive trigger pulls. Issue 1 Scanning The broken clip is scanned with an EinScan 3D scanner. This scan is used as a reference in CAD to model a replacement part.

Dec 31, 2023

Reverse engineering of a Dremel 12 V battery charger. The chargers specifications according to the manual: Voltage range: 1-3 cells, 3,6 - 12 V Charging current: max. 1500 mAh Reverse Engineering Two pictures were taken to trace the connections on the pcb. Since this is a simple one sided pcb this was fairly easy. The pcb has the markings: PCB1857V1

Sep 23, 2023

This was my first attempt at milling my own single sided circuit board on my 6040 CNC router. Along the way I had some issues with the pcb blanks bowing, but I ended up with a functional LPT to USB adapter for Estlcam.

Sep 28, 2020

The name audio spectrum analyzer is probably a bit too high trotting. A more befitting name would be funny looking graph display that changes with the music. But this was my second electronics project in 2018. It uses only through-hole components on a two-layer PCB.

Jul 1, 2018

Features The software runs on a RPi 3b. The handheld features a 3.5′ 320×240 px TFT-LCD screen that I salvaged from a car rear view monitor but via the RPi’s onboard HDMI interface, it can also be connected to a larger monitor. On the front of the device, there are eleven buttons with four additional ones on the back. The backlight metal button on the side is the console’s power switch which is connected to the “PowerBoost 1000C” charge controller with an integrated 5.1 V boost converter from Adafruit.

May 1, 2017