James decided to reverse engineer car ultrasonic parking sensors. These sensors have integrated electronics that handle all the measurements. They are connected to the car’s internal computer via a low-speed single wire CAN network. James provides pinouts, protocol interface, and some source code to interface with them. Since I know a thing, or two, about […]
Author Archives: DP
BootDrive loads Arduino sketches from an SD card
Kevin wrote an Arduino bootloader that loads sketches from an SD card. BootDrive is open source and available on GitHub. Announcing the formal release of BootDrive for Arduino. If you’ve been reading the blog, you know that I’ve been working with Justin Shaw of Wyolum labs to enable their I2SD (Arduino clone with a micro-sd […]
MCP2200 breakout board free PCB built
Megabug built a free MCP2200 breakout board. MCP2200 are USB-to-UART converter chips by Microchip. In fact they are PIC18F14K50 microcontrollers programmed with the USB-to-UART firmware. We were able to hack one and program an open source USB stack into it. If you build a free PCB we’ll send you another one! Blog about it, post […]
23K256 breakout board free PCB built
Ian Griffiths built a free 23K256 breakout board. The 23K256 is a 256Kb SPI SRAM memory chip, but it comes in DIP too so we nixed this project. If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for […]
A basic introduction to Phase Locked Loops
Kenneth was curious about Phase Locked Loops so he decided to dive into them. PLLs generate an output signal that is phase-synchronized to an input signal. They are widely used in telecommunication, radio, and computer systems. One place we commonly find PLLs is the frequency multiplier circuit inside microcontrollers. The inevitable next step was to […]
Open source hardware presentation by Erik de Bruijn
Erik let us know about his presentation on open-source projects. It uncovers some of the motivation behind an open source project, as well as the means to achieve your goals in open source. I talk about the non-rival nature of information and how a culture of sharing enables the emerging phenomenon of open hardware. Via […]
#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. This week we have a guest PCB, the Itead mystery pcb. Use your coupon to pick this PCB, or any other in the […]
Alpha testers needed for RX/TX Lab’s open source solar powered GPRS/GSM sensor platform
TX/RX Labs open source project BACON is nearing the alpha testing stage. They have released an announcement asking for any developers wishing to get involved with Alpha testing to contact them. Project BACON is MSP430 based solar powered GPRS/GSM sensor platform. It has on-board battery management, GPRS/GSM modem, 3 axis accelerometer, mems mic, GPS, temperature […]
USB LCD Backpack PIC18F24J50 free PCB build
Dolabra built a free USB LCD backpack PCB. His version is one of our prototypes based on the PIC18F24J50 microcontroller, which is different to the one we sell at Seeed with a PIC18F2550 uC. He had to do some coding to adapt it to the new chip. If you build a free PCB we’ll send you […]
Review of the XC9572XL clone by Numato Lab
A few weeks ago Numato Lab ported our XC9572XL CPLD breakout board to KiCad. Hilipka got one of their assembled boards for free and wrote a review. its quite a nice board, feeld of high quality even included an oscillator the JTAG header is not labeled at all, making it difficult in the beginning I […]
Open source USB HID joystick firmware update
Kiran updated the firmware on his DIY joystick. It features 10 buttons and an analog joystick all controlled via a PIC18F14K50 USB microcontroller. The firmware update provides mapping for all 10 buttons, while the next update will add functionality to the analog stick.
USB IR Toy free PCB build
Kenith built the USB IR Toy free PCB. You can use it as a remote control with your computer, view infrared signals on a logic analyzer, or capture and replay remote control buttons. Dangerous Prototypes never ceases to amaze me with how they are poster child of open source hardware. You can literally go back […]
Vetinari’s random-tick clock
Mick decided to build Vetinari’s clock based on WaitingForFridays project. Lord Vetinari, from the Discworld book series, has a clock in his office that is designed to make his visitors feel uncomfortable by having the second hand move at irregular intervals while still keeping exact time. The erratic second hand in Mick’s project is driven […]
App note: ATXmega USB Hardware Design Recommendations
Here is an design recommendation from Atmel about implementing USB on AVR XMEGA microcontrollers. The article provides all the basic information you’ll need to get started with designing USB devices with the XMEGA. This document is written for hardware designers to help them develop their applications. It assumes that readers are familiar with the AVR […]
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 we have a guest […]
App note: Lamp dimmer using PIC12C508
Here is a reference design from Microchip describing how to built a Light dimmer with a PIC12C508 and a few discrete components. The circuit uses a simple zener voltage doper, to drop the voltage from mains to 5V required by the PIC. Watch out, there is live mains voltage involved. This reference note describes an […]
App note: Designing with ultra fast comparators
Here is an app note from Linear Technology covering the problems and solutions of designing circuits with ultra-high speed comparators. More specifically the problems associated with using their LM1394 7ns single supply comparator. The mechanics and subtleties of achieving precision circuit operation at DC and low frequency have been well documented. Relatively little has appeared […]
App note: Protect your batteries from reverse insertion
Rsdio tipped us to an app note from Maxim describing how to protect your Lithium Ion batteries from reverse insertion into the charger. The circuit is a Li-Ion battery charger with an added analog comparator designed to detect when then battery is inserted the wrong way and disconnect it from the charger. Combining a linear-mode […]
Open source micro-ampmeter with autorange
Here’s an open-source micro-ampmeter with autorange. It can measure current from 0.05μA to 10mA. It’s designed on a single layer PCB, making it easy to build with DIY etching techniques: The micro-ampermeter described here is intended for experimenting with low-power devices. I have just a general multi-meter in my home lab, which is not very […]
Drag soldering tips for Hakko 900M series and compatibles
A few weeks ago we wrote about hollowed-out chisel tips, and how good they are for drag soldering. Unfortunately they are either hard to find, or made only for expensive soldering irons. There also seem to be some patent disputes that keep them out of the US market for most major brands. Recently we were […]