Nuclear physic applied in smoke detectors

Robert Gawron writes: Not many people know, but in some smoke detectors, radioactive materials play an essential role. Today I will present one of those devices, and my -successful- attempt to reverse engineer it and get the circuit diagram. Those smoke detectors uses a small amount of Americium-241 (chemical symbol: Am) obtained in nuclear reactors […]

Brute force computation for cheap log digital potentiometer

Michael from Acidbourbon writes: This article covers the attempt to build a digital logarithmic potentiometer out of two linear potentiometers. The benefits of this concept Linear digital potentiometers can be easily procured and don’t cost much There are IC packages with two or four modules inside anyway The resulting logarithmic potentiometer is very flexible in […]

RC2014/LL and RC2016/10

Scott Lawrence has written an article detailing his Z80 homebuilt computer, the RC2014: The RetroChallenge is upon us again! This time around, I plan on working on my Z80 homebuilt computer, the RC2014. (Website for RC2014, Order a RC2014) For a few months now, I’ve had my RC-2014 computer built, and modified to be an RC2014/LL […]

DIY USB power bank from laptop battery

A DIY USB power bank made from an old laptop battery from DoItYourselfGadgets: A situation many can relate to: an empty smartphone battery and no outlet around! That’s exactly why I recycled an old laptop battery into an USB power bank. This article will show you the basic powerbank circuit consisting of Lithium cell charging circuit, […]

A low-voltage disconnect for 12 volt lead acid and lithium batteries

KA7OEI writes: The avoidance of overcharging is usually pretty easy to avoid: Just use the appropriate charging system – but overdischarge is a bit more difficult, particularly if the battery packs in question don’t have a “protection board” with them. Lead acid batteries (almost) never come with any sort of over-discharge protection – one must […]

9V/1kV DC/DC converter

Robert Gawron’s home insect electrocution project: Currently I’m working on a device to electrocute home insects like cockroaches, progress is small because they are smarter than I thought, but that’s a different story. For that project I had to find a source of sufficient high voltage and output power. Presented in previous post 5V/400V converter […]

DIY smart glasses

Harris has been working on his DIY smart glasses: The glasses themselves are based around an STM32F051K8 microcontroller (LQFP32 for easy soldering!). All the firmware is custom written though I got the LCD driver initialization codes from the BuyDisplay examples. The firmware is written using a somewhat “co-operative scheduling” with interrupts methodology and for most […]

Using Tronsmart Pavo M9 for HDMI input streaming

Danman wrote: Thanks to a tip of my reader, I found a relatively cheap (69Eur) Android box with HDMI input and record ability. I thought that it should be possible not only to record the HDMI input but also to stream it in realtime so I ordered one for experimenting. Full details at Danman’s blog.

Hacking a UART where there never was before

Thanks to Andrew for sharing – check out the full post on their blog, MOAM Industries. As part of a prototype developed 12 months ago I was tasked with reading measurements from a blood pressure cuff [sphygmomanometer] in real time. Not surprisingly there are no consumer level devices that have a serial interface because what […]

Behringer v-tone GMX212 Hybrid tube amplifier mod

Davide Gironi wrote a post on his blog showing how he modified the Behringer v-tone GMX212 Hybrid tube amplifier: For this project I’ve used 12AX7 vacuum tube. This tube is one of the most used for the guitar preamplification. So there are many resources available on web. The first problem i faced it’s the power stage. […]