Nano current meter based on an ATtiny84

Johnson Davies published a new build: This project describes a simple low-current meter I devised to check the sleep current of different microcontroller circuits, such as ones based on AVR microcontrollers. It’s capable of measuring currents of between 10µA and 30nA with reasonable accuracy, using an ATtiny84 and a few other low-cost parts Project details […]

Free PCB coupon via Facebook to 2 random commenters

Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three […]

DIY Analog resource monitor for your PC

Sasa Karanovic posted detailed instructions of how to build a physical dashboard for your PC, that is available on GitHub: The overall architecture is very simple; There is a python script that is running on a PC and collects CPU, memory, network and GPU usage. Then, it sends that information over serial COM port to […]

ATTiny85 Pulse oximeter with photoplethysmogram (PPG) display

tinyPulsePPG, an ATTiny85 Pulse Oximeter with Photoplethysmogram (PPG) display by Jeff Magee: This project implemented on an ATTiny85 displays a moving Photoplethysmogram together with pulse rate and estimates of SpO2 – blood oxygen percentage. It uses an SSD1306 128×32 OLED display and a Max30102 sensor. It is emphasised that this should not be used for […]

Current meter based on ESP-12E and LTC4150

Victor Chew made a simple current meter based on ESP-12E, LTC-4150 and SSD1306 OLED module that measure the average current draw of a variable load accurately: The meter is powered by the micro-USB port on the ESP-12E. I soldered header pins onto the IN and OUT terminals of the LTC-4150. The whole idea is that […]

UPDI Programmer Stick

Johnson Davies designed and built this UPDI Programmer Stick based on an ATmega328P, that is available on GitHub: This is a USB-stick sized UPDI programmer, for programming Microchip’s new 0-series and 1-series ATtiny chips from the Arduino IDE It’s based on an ATmega328P, and is essentially an Arduino Uno on a USB stick, so you […]

Free PCB coupon via Facebook to 2 random commenters

Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three […]

Single diode temperature sensor with Arduino ICU (& reverse-bias leakage)

Use a single diode as a temperature sensor with Arduino ICU Our LED light-sensing experiments lead to an interesting observation: When these loggers are left running overnight they still produce readings because reverse-bias ‘leakage-current’ eventually triggers the Interrupt Capture Unit (ICU) – in the absence of any light. The speed of this self-discharge depends on […]

#FreePCB via Twitter to 2 random RTs

Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week: Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch […]

JesFs – Jo’s Embedded Serial File system

suchende tipped us to the small File system for NOR flash: The main problem for “very small devices” – until now – was the “File System”: everybody knows “FAT”, “NTFS”, … but have you ever thought of a file system on a small chip? Or even inside of a CPU? No problem, with the right […]

Linear Nixie tube HAT for the Raspberry Pi

Mark Smith has been working on a HAT for the Raspberry Pi that can drive two IN-9 or IN-13 linear Nixie tubes: This project as described in www.surfncircuits.com came about because I needed a retro looking linear meter for my espresso maker water tank. I’m always running out of water in my espresso maker, and […]

#FreePCB via Twitter to 2 random RTs

Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week: Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch […]

JTAG debugging the ESP32 with FT2232 and OpenOCD

Erich Styger has written an article on how to use an inexpensive FTDI evaluation board as JTAG debug interface to debug ESP32 based devices: In “Eclipse JTAG Debugging the ESP32 with a SEGGER J-Link” I used a SEGGER J-Link to debug an ESP32 device with JTAG. I looked at using one of the FTDI FT2232HL […]