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 […]
Author Archives: DP
Modifying RAM SPD data
Zak Kemble wrote a post on his blog showing how he modified the RAMs Serial Presence Detect (SPD) data: Recently I brought some low-power Mini-ITX motherboards; a Gigabyte GA-N3050N-D3H and a Biostar N3050NH. These boards take SO-DIMM DDR3 RAM, the sort found in laptops. The boards are both pretty much the same, however the Gigabyte board lacks […]
ChipStick – A small scale experimental Forth machine
Ken Boak blogged about his ChipStick PCB build: The ChipStick design has the following features: MSP430FR2433 with 15.5K FRAM and 4K SRAM External SRAM or FRAM device connected via SPI on USCI B0 CH340G USB to serial converter IC on detachable section of board 3V3 voltage regulator Reset Switch and User LED 20 Pin DIL footprint to allow insertion […]
Having cheap PCB’s made, part 2
Batches of PCBs from Ivo of Knutsel.org: The first batch was a new run of the LivingColors Arduino shield. The second batch was a breakout board for the NiceRF SX1276 LoRa module. Here I experimented a little with contour routing. The third batch was an adapter board to use no-name CC2500 modules in boards designed for […]
Mains 230VAC isolator
Jaanus Kalde has built an isolator box: Probing mains powered schematics is hard. Most oscilloscopes are earth referenced, so connecting ground probe to random spot of mains connected device will make a small explosion. Also there is the risk of electric shock by touching wrong part of the schematic while being in contact with something grounded like […]
Low voltage power supply unit
Dilshan Jayakody writes: In this post we introduce simple and flexible, regulated low voltage power supply unit. This power supply has provision for 4 outputs such as 1.5V, 1.8V, 2.5V and 3.3V. We mainly build this low voltage power supply unit to test (and power-up) low voltage MCUs, CPLDs and radio receivers. For this power […]
Building a simple circuit probe
Vicente Jiménez has published a new build: Sometimes you need to check one circuit and test some of its nodes. Usually a tester in voltage mode is a good solution, but it has a pair of problems. First, it measures about zero both when the node is driven at zero volts and when the node […]
An almost-GHz active differential oscilloscope probe (Part 3)
Christer Weinigel wrote a series of three posts about how he built a active differential scope probe which is usable up to about a GHz: This is part three of a series about building a active differential oscilloscope probe. Part 1 covered why I wanted a differential probe and the design of it. Part 2 […]
#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 […]
Building a better RTL-SDR TCXO
Craig posted an article describing how he built a 28.8MHz RTL-SDR TCXO, that is available on github: Here’s a scratch-built 28.8MHz TCXO capable of +-1ppm stability from 0C-55C; best of all, it’s not only easy to build, but is designed entirely from readily available and inexpensive components. For improved temperature stability, the main oscillator can […]
Counterfeit Macbook charger teardown: convincing outside but dangerous inside
Ken Shirriff writes, “What’s inside a counterfeit Macbook charger? After my Macbook charger teardown, a reader sent me a charger he suspected was counterfeit. From the outside, this charger is almost a perfect match for an Apple charger, but disassembling the charger shows that it is very different on the inside. It has a much […]
19th century radio technology meets the Beaglebone
Ashish Derhgawen built a coherer-based receiver with a simple decoherer mechanism, and connected it to a Beaglebone to decode the received signals: In my last post, I described how I made a spark-gap transmitter and receiver. For the transmitter, I used a car’s ignition coil to produce high voltage sparks, and for the receiver, I […]
Atmel SAM D09 Development board
Dan Watson has designed a development board for the Atmel SAM D09 microcontroller: The Atmel SAM D series of 32-bit microcontrollers includes several devices, each with a long list of features at great prices. Perhaps the best known of the series in the maker community is the SAM D21 due to its use on the […]
Free PCB Sunday: Pick your PCB
We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will […]
App note: Iris Recognition SFH 4780S
This application note from OSRAM describes the use of the SFH 4780S in iris recognition (iris scanning) as illumination module. Link here (PDF) Personal authentication is becoming a key requirement for various electronic devices. Besides of the pin number, today most systems are based on so called biometric “properties”. Biometrics can include fingerprints, facial features, […]
App note: Eye safety of IREDs used in lamp applications
This application note from OSRAM describes the possible hazards of infrared LEDs (IREDs) used for lamp applications with respect to the IEC-62471 standard and how to classify IREDs according to different risk groups. Link here (PDF) As the radiated optical power of light emitting diodes (LEDs) has increased in recent years, the issue of eye […]
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 […]
Building a “$5 Forth computer” – first steps
Ken Boak writes: In this post we look at a new MSP430 FRAM based device – the MSP430FR2433. It has 15K of FRAM, 0.5K of Info FRAM and 4K bytes of SRAM. As well as the memory, there are 3 serial communications interfaces, a multichannel 10 bit ADC and 3 timers. All of this in […]
nRF24L01+ 2.4 GHz wireless connectivity with the tinyK20 board
Erich Styger writes: I’m using the tiny and inexpensive Nordic Semiconductor nRF24L01+ transceiver (see “Tutorial: Nordic Semiconductor nRF24L01+ with the Freescale FRDM-K64F Board“) in many projects: it costs less than $3 and allows me to communicate with a proprietary 2.4GHz protocol in a low power way (see “IoT: FreeRTOS Down to the Micro Amps“). I have […]
OpenGarage, an Open-source WiFi garage door opener
Ray Wang has published a new project called OpenGarage, an open-source garage door opener based on ESP8266 and the Blynk app: Today I am very excited to introduce you to OpenGarage — an open-source, universal garage door opener built using the ESP8266 WiFi chip and the Blynk app. I’ve wanted to finish this project for a […]