An electronics geek blog, dedicated to sharing and open source. Check out my stores: EU / EU & US .
... if only it was as simple as connecting their terminals together! Project Context You may remember the custom 18650 cell-based battery I made a while back... well, I assembled more of them ! I therefore figured I should come up with a way of connecting several of them together in order to make a bigger "battery" out of them (because... why not?). Before digging into this project, I should first…
so many measurements now made possible! Project Context Have you ever wondered how well a given component (voltage regulator, operational amplifier, ferrite...) could filter the noise coming out of your power supply? In theory all of these components' datasheets should provide you with a figure of merit, typically the Power Supply Rejection Ratio ( PSRR ). But what tool should you use to make sure…
... without making any fire! Project Context This project isn't really a creation, but more like something I assembled together during the little spare time I could find. It all started when I found a listing for 100x salvaged 18650 li-ion cells on a local auction website. Not having a home to build a powerwall into, I thought of the next best thing to do with them: make my own 48V backup battery…
Or how to snoop on targets by looking at their current consumption... Introduction For several months, I had the chance to share an office with a security researcher whose hobby was to break the ESP32 AES engine by only looking at its current consumption . His measurement setup was not ideal: long wires, a noisy current probe that required lots of trace averaging to measure anything... something…
Or how to use a common component for a completely different purpose! Introduction For several months, I had the chance to share an office with a security researcher whose hobby was to break the ESP32 AES engine by only looking at its current consumption . His measurement setup was not ideal: long wires, a noisy current probe that required lots of trace averaging to measure anything... something…
I started experiencing an issue with my A5 speakers: my right speaker was getting quieter than the left one! I don't know about you, but for me this was one of these issues that would constantly annoy me as it progressively got worse.... there's so much an operating system's equalizer could do! As customer support let me know that replacement parts weren't made anymore , I decided to sacrifice a…
A very small form factor project, not only measuring an object's speed but also displaying it! With its UART interface, interfacing with Arduino platforms is dead simple too! Introduction If you follow this blog, you may have noticed that this is my third project using doppler sensors, and my second with the CDM324 . This tiny sensor is just so neat for its price! A quick refresher on the Doppler…
A 7Hz High Pass Filter to measure voltage ripple on power supply rails. Project Context Following the making of my DC-coupled low frequency, low noise amplifier board I discovered that a crucial piece of equipment was missing from my toolkit if I wanted to measure voltage ripple on power supply rails: a low corner frequency high pass filter , or DC-block . Such device allows you to remove the DC…
Sometimes one may want to measure tiny signals ’ frequency contents at frequencies just above DC . How tiny you may ask! Well, my arbitrary goal for this project was to clearly measure the thermal noise of a 50 ohms resistor (around 0.9nV RMS for a 1Hz measurement bandwidth at room temperature) to be sure to be able to measure any device output I may encounter in the future (maybe audio…
A 60 Nixie tubes contraption that I postponed for 5 years... Introduction It has been three years since my last blog post, and four years since my last published project.... time flies! As you may have guessed, most of this time went into my family and the Mooltipass project , with its third device successfully funded through Kickstarter! It's quite hard to find the time for the funky side…
Very few are lucky enough to use such a piece of equipment... so I figured I'd share this experience with you! Let me first start this write-up by apologizing for the lack of recent articles. As you can imagine, I've been fairly busy working on the Mooltipass ecosystem , and more recently on an upcoming wireless device! Unfortunately this article is not going to be about its antenna (we're not…
Made using only components from my stock ! Why This Project? For once, this project was not for me... it was for my wife ! Every morning she takes the bus then train to go to work. If she misses her train, she has to wait for more than 30 minutes for the next one. Not missing her bus is therefore quite important. Where we live every bus station has a display letting you know in real time when the…
I couldn't believe my eyes when I saw how tiny that sensor is ! 2023 Edit - New Project Version! I just made an improved version of this project, check it out here ! Otherwise, feel free to read about the non-MCU based version below: The Doppler Effect I'm sure you're quite familiar with the Doppler effect: you send an RF signal at a given frequency to a target, and if this object/person is moving…
Or how to try to spend as little time as possible programming several thousands MCUs .... Why.... Just Why? As you may know I started the Mooltipass offline password keeper project more than 2 years ago. Together with a team of volunteers from all over the globe I created two Mooltipass devices which were successfully crowdfunded through Indiegogo and Kickstarter , raising a total of around $290k…
I usually never use libraries... but made an exception for these quick projects ! I'm pretty sure that most people reading this very article know about the (very) cheap ESP8266 Wifi module . A bit more than a year ago, I actually made a small development board for it, which was recently used in the connected lamp that wakes me up. While what follows pales in comparison to what cnlohr has…
It's always fun playing with dangerous voltages ! The Idea For quite a while I've had this project idea in the back of my head that would involve using many Nixie tubes . These funny looking cold cathode displays were actually introduced during the 1950s and unfortunately need quite a high voltage to work (from 100V to 180V depending on the type). This meant that I had to find an easy, cheap and…
Did you know that most ceramic capacitors lose up to 80% of their capacitance near their voltage ratings? The Idea Not every electronics enthusiast knows that a ceramic capacitor's capacitance changes with the voltage you apply to it . This can be particularly annoying when designing RC filters or DC/DC power supplies... you might therefore think your capacitor's value is 10uF when it actually is…
I've always wanted to play with these 10W RGB LEDs! The Idea So for some reason I bought 2 IKEA lamps at a flea market. As IKEA furniture has a long history of being hacker-friendly, I figured they shouldn't be an exception to the rule. My plan? Fit a few 10W RGB LEDs in there together with an ESP8266 to use the final result as an alarm clock . The Schematics When you are dealing with a LED…
This is one of these "just because" projects... The Idea I'm sure that most of you are familiar with the stroboscopic effect . To paraphrase wisegeek , it is a phenomenon of human visual perception in which motion is shown to be interpreted by a brain that receives successive discreet images and stitches them together with automatic aliases for temporal continuity. In short, motion is an artifact…
$120k and a year after my previous article, you might be interested to know what happened behind the scenes... Let's pick things up where we left off I can't believe the Mooltipass project is already more than 15 months old... it has been (and still is) an incredible ride. In my previous article the project had only started 4 months earlier. I'm happy to say that during the months following that…