Jbeale reviewed how much current small USB WiFi routers draw. His intent is to connect them to the Raspberry Pi which can only provide 140mA over the USB port. It turns out that from Internet connectivity the routers draw under 100mA, but if used in high speed LAN operations the current draw jumps over R-Pi’s […]
Author Archives: DP
LTC4370: current-sharing controller with reverse current blocking
Here is an interesting part from Linear Technology, it’s the LTC4370 current-sharing controller, with reverse current blocking. Basically it allows you to tie two power supplies in parallel, without the fear that one will source more current than the other. It also has built in protection that prevents the current from flowing into the supplies. […]
Bus Pirate RFM12B radio data module demo
Hacromatic posted a tutorial on interfacing RFM12B radio data modules with the Bus Pirate: We’re working with some RFM12B RF modules, and needed to verify that they were working properly, so we used a Bus Pirate. We thought it’d make a nice intro to SPI on the BP so we wrote it up. Via the […]
App note: Theory behind ground loops
Analog Devices discusses ground loops and how to manage them: Transmitting data over long distances is fraught with potential problems. A ground loop can be a source of interference that can induce a noise voltage between the grounds on either end of the transmission. If this voltage is large enough, it can cause data errors […]
App note: Using and understanding voltage references
This tutorial on voltage references covers theory and how it works in practice: When specifying a reference, keep in mind that initial accuracy, temperature coefficient and long-term stability all play a role in overall accuracy of the finished product. By taking some care in applying the reference, and by avoiding some key pitfalls, the reference’s […]
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: Circuits and principles of high side current measurement
Maxim describes several high side current measurement circuits: This application note describes the use of current sense amplifiers, differential amplifiers and instrumentation amplifiers to measure battery charge and discharge currents in portable equipment, computer notebooks and USB accessories. It compares high side current sense amplifiers with low side differential amplifiers and recommends selection criteria for […]
App note: IrDA stack for infrared data exchange
IrDA is a set of protocols for exchanging data over infrared light. It’s significantly more complicated at the protocol level and hardware level than simple IR transmitter like remote controls. To get started in IrDA you’ll need some software to encode and decode packets, Microchip describes their IrDA stack in this app note: The Microchip […]
Workshop Update for August 24th, 2012
Setup the alternate look for the Open 7400 Competition mini site. Still a bit to do. Also fixed a problem with the social media icons under Firefox latest versions as long as we were in there. Next week we have a bunch of scratch and dent projects to give away. These are working projects, but […]
Via options: Tenting, capping, plugging, or filling
From comments on our earlier Poision via effect in manufacturing post, Bearmos shared an article about via options in PCB manfacturing: On the PCB side of things, here’s an article from a PCB fab that goes over a couple of the via options: via tenting, caps, and plugs (PDF!). This just landed in my inbox […]
Developing FFT applications with low-power microcontrollers
Squank provided some links for developers who’d like to use the Fast Fourier Transform in low-power MCUs. FFT is an algorithm used in DSPs to quickly convert time-based functions to spectrum-based function, and vice versa. Via the forum.
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. More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times a every week: Free PCB Sunday. The classic. Every week, […]
Gaining experience with schematic and PCB work
Wardy gives some advice on how to improve your schematic and PCB design skills. His advice is to clone consumer products with available schematics. He provides links to a few examples to get you started. Using a realistic design will confront you with the kind of obstacles that present themselves to the original designers themselves […]
Week in (p)review August 24, 2012
Here’s a summary of major developments over the last week. Free PCB Friday is coming up soon. Workshop Video #36: Beers in Bunnie’s Workshop Workshop Video #35: Singapore Mini Maker Faire 2012 report 3D Model: FT311D Breakout Board Check out Matseng’s IR remote control intervalometer in the project log forum Workshop Update for August 23rd, […]
Resurrecting a dead Bus Pirate using a GoodFET and a floppy cable
Bob Sheep tweetted: Resurrecting a dead Bus Pirate using a GoodFET and a floppy cable. Get your own Bus Pirate for $30, including worldwide shipping.
Workshop Update for August 23rd, 2012
Edited Beers in Bunnie’s Workshop video. Please check it out. Finished the “nixie pile” driver and holder boards, and sent them to Seeed Studio’s PCB service. They’ll be black. It seems Maker Faire New York acceptance letters went out today, we will be there with Louis from the San Francisco taco crawl and videos, and […]
Emicon-Fun inductor/capacitor lessons
Riktw writes to inform us of a tutorial site covering the theory behind capacitors, and inductors, as well as noise suppression filters. The site is actually a blog, with new posts being posted every month or so. When looking for a small switching power supply module at the website of Murata I found this Emicon-Fun! […]
Powering projects from Li-polymer cells
Sjaak gave an example of powering a project from Li-polymer cells. His design uses the MCP73811 to handle the charging, while the TPS61200 DC/DC converter maintains 3.3V on it’s output regardless of the battery voltage. Via the forum.
40pin IDE cable to 40pin breakout board
Chris designed this simple 40pin IDE to 40pin ”0.1 header to easily breadboard with his DE0-Nano FPGA development system. While it was designed for the DE0-Nano, any board that uses the 40 pin IDE header can be broken out in this way. He provided in-depth instructions on how to build your own, including the design […]
Theater light show project
Here is a light show project from North Street Labs built for the Hippodrome. They built 7 large LED panels that are controlled trough an RS-485 link. Each panel has 86 RGB LEDs and an Arduio controlling them. The build is well documented if you want to try this at home. Via Hacked Gadgets.