Stephen added his entry in the Open 7400 Logic competition, he made a LCD backpack that uses the SPI interface. Using two 74LS595 serial to parallel shift registers connected in series, he successfully sends data to the 16×2 LCD and adjusts the backlight brightness, by sending 2 bytes over the SPI. The first byte to be sent is displayed on the LCD, and […]
Author Archives: DP
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, […]
PIC LCD backpack free PCB build and hack
Having built a free PIC LCD backpack PCB, Ezflyr decided to hack its pins to use with his temperature and humidity sensor. He successfully adjusted LCD backpack’s firmware, and developed a small app to display the temperature and humidity information on the computer. Via the forum. If you build a free PCB we’ll send you another one! […]
Soldering iron tip selection guide from Hakko
Arhi contacted us about this useful guide for selecting the right size and shape tip for your soldering iron. First part of the article compares various diameter tips used over the same soldering point. Graphs show that for the fastest work-flow is when using larger or same size tips as the solder point. The second […]
Arduino solar radio
Simon built a solar powered Arduino FM receiver. Using a solar panel to charge the batteries, this Arduino controlled device can work without the need to recharge. A SI4073 FM tuner ICs output is connected to a TDA7051 integrated amplifier, while the Arudino controls the channel selection of the FM tuner. There is a multi-position switch used […]
Is soldermask required for fine pitch IC soldering?
Intrigued about a discussion on the forum about whether soldermask is needed between fine pitch pads, Brian decided to test it. In the video of the test he placed solder paste on both the FR4 board material, and the soldermask, as well as some on a tined pad. Once done reflowing his results were in. Both the FR4 and the soldermask acted the […]
Surface mount soldering tutorial
EEVblog made a SMD hand soldering tutorial. In the video Dave explains how to solder small SMD capacitors and resistors, all the standard size pitches for ICs up to a 0.5mm pitch, as well as some tips how to use large thermal pads, like adding thermal paste or preheating the board and the IC.
Debugging a glitch on a CoolRunner-II project
While working on his CoolRunner-II 50Mhz counter project jbaele found a bug. The reset line was showing a serious glitch when the stop signal was sent to the counter. The glitch was found to be the result of having the stop and reset signals next to each other on a ribbon cable. The capacitance of […]
Oldest working Weller soldering tool contest
All-Spec Industries anounced the oldest working Weller soldering tool contest. All that is needed to enter is to send a picture of your tool to them, along with your name and shipping adress. First prize is a Weller WD1002T soldering station, and all entries recive a All-Spec Mug Boss. Via the contact form.
Bus Pirate Qt GUI
Vincent is coding a Bus Pirate GUI with Qt. Being cross platform it should run fine under Windows, Linux, and Mac. So far it is a modified console with firmware update support. A code repository is available. Via the forum. Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.
What are the topics you need to know to master microcontrollers?
Chuckt asked what goals important to master microcontrollers. There’s been some good suggestions so far, which are consolidated on the wiki: Basic Pins/port/direction (LED flashing) PWM (LED intensity) Advanced UART communication (when and how to use max232 chip) SPI communication I2C communication CAN communication Interrupts (pin – detect button press, UART – communication) Hardware timers Interfacing an […]
SSL/TLS library side by side comparison
Brian stumbled on this side by side comparison of SSL/TLS libraries and gave his review of it: So in summary of what code bases I find usable from a licensing prospective: TropicSSL and axTLS are clear winners in terms of the license CyaSSL and PolarSSL are GPL V2 + FLOSS which is less desirable Next I looked […]
7400 competition entry: Analog comparator
Joseph built an analog comparator for the Open 7400 Logic competition. Using two NAND 3-input gates and a D-type flip-flop, he build a clocked analog comparator. After reviewing the internal composition of a CMOS NAND 3 gate he noticed that two of them connected in the right way make up a comparator. To make his own version he used a D-type flip-flop to […]
How-to use surface mount parts with a breadboard
Pppd shared a tip for using surface mount parts with a breadboard, mount them on 0.1″ pin header: Also, I’m probably not the first one to do it this way… but if you don’t like through-hole parts just as much as I hate them you may want to use surface mount resistors, capacitors or even […]
Voltage monitor for car’s battery and its charging system
Raj designed a car battery volt-meter. The core of the project is a PIC16F1827 which uses its internal fixed voltage reference FVR and ADC to precisely measure the battery voltage. Measured voltage is displayed on a 4 digit 7 segment display. His circuit is connected to the car’s battery through a standard car lighter jack. Via the […]
I2C controled 8 relay driver switches plug-in devices
Megabug posted his I2C relay driver board for controlling 8 outputs. It controls 8 relay switches in which one pin of each switch is common, while the other pins are available through 8 screw type headers. It uses the PCA9554 8bit I2C port expander to drive a ULN2803A buffer which in return drives the relay coils. All buffer input […]
#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 […]
7400 competition entry: Animated LED Christmas sign
Raj entered his Animated LED Christmas sign into the Open 7400 Logic Competition. Having already build a PIC controlled version, he wanted to try and control the sign using discrete logic only. The individual letters are build from red LEDs and run of a 32V power supply. Check out the video of this project below. Via […]
HAKKO soldering pencil driver update
Arhi compares his soldering iron driver with commercially available products. After designing and building a open source soldering station for Solomon or Hakko soldering pencils, he posted a full analysis of his project. While his driver has some overshoot, once it stabilises the temperature has less swing then the original drivers. With some PID tuning even better […]
Controllable aquarium moonlight strip
Theatrus build a controllable aquarium moonlight strip on the fish tank bubbler. Royal-blue Osram high power surface mount LEDs provide the lighting, and an ATmega88 the control. RS485 port is used for control. All of the design files should be available shortly. Its quite potent (visible with the main 6x80W T5s running). Its easy to mount […]