Plus Too Apple replica on FPGA


Steve Chamberlin over at Big Mess o’Wires presents the Plus Too, a working hardware replica of the Macintosh Plus and Macintosh 512Ke computers.

The original Macs contained a Motorola 68000 CPU and about half a dozen major support chips, with all of the Mac-specific behaviors and OS routines defined in a 128K toolbox ROM. Plus Too uses an FPGA to model the Mac’s IWM (floppy controller), SCC (serial ports), VIA (general purpose I/O), mouse, and keyboard hardware. The toolbox ROM data was copied from my real Mac Plus (nicknamed “Lonely”) for use with Plus Too.


The project is built on an Altera DE-1 FPGA dev board and at this time implements only the absolute minimum of hardware necessary to boot the computer. The disk is read-only, and there is no keyboard, sound, SCSI, serial ports, or real-time clock. In the next version, Steve plans to use a custom built board and a real 68000 CPU, and add the physical connectors necessary to use a real Mac Plus mouse and keyboard if desired.

For all the details on this project, check out the Plus Too build log.

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 14pF between the wires had enough leakage to hamper the project.

Via the forum.

Get the CoolRunner-II development board for $15 and XC9572XL dev-board  for $15.

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.

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 HD44870  display
  • Analog-Digital Conversion (ADC)
  • Digital-Analog Conversion (DAC)
  • EEPROM (store stuff)
  • Sleep/low power (battery operation)
  • Bootloaders (memory map, self-writing)

Broad concepts

  • Multiplexing (timers, pins)

Image by David Henry : CC BY-SA

Via the forum.

DIY Arduino Ambilight using ShiftBrites


Don built an Amblight for his home theater PC. He put together this tutorial describing his build of a multichannel Arduino-based Ambilight. He estimates the BOM at $40 (in addition to the Arduino).

The bill of materials include 6+ ShiftBrites (your call, I wouldn’t do less than 6 though), a printed circuit board, wire, and headers. Additionally this will require all of the components needed to get over 0.5 Amps at 5.5-9V DC on to the board to drive the ShiftBrites; this cannot be reasonably done over USB power. My ultimate goal here is to give others some ideas on how to go about this project for less money than it would cost to essentially buy everything in a kit. I went in to this trying to be resourceful and I feel pretty good about how it turned out.

Read more at Don’s Projects.

Thanks Hoz. Via the contact form.

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 at the code bases.

CyaSSL looks the most complex, and that is born out in terms of the code size (27kLOC). Meanwhile PolarSSL/TopicSSL and axTLS come in at less than half of that with 12-14kLOC.

In terms of file/module organization TropicSSL/XySSL/PolarSSL looks a bit better than axTLS at least at first glance.

I conclude that if I want to have the most robust SSL/TSL I should look to port CyaSSL. If I want the freest SSL I should adopt axTLS or TropicSSL/XySSL. axTLS is still maintained by the original author while XySSL is not.

Via the forum.

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 save the output value from the gate before it resets on the next cycle. Schematic, as well as some logic gate theory, is available on his site.

Via the contact form.

CoolRunner-II breakout free PCB build

Schazamp has built a free CoolRunner-II breakout board. He had success building a 8bit binary to 3X4bit decade converter which he will use to drive a 7 segment display via the 74hc4511 driver.

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 the free PCB drawer.

Get the CoolRunner-II development board for $15 and XC9572XL dev-board  for $15.

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 transistors on your bread board circuits. There’s an easy way to do that, just use the pin headers and solder the 1206/0805 parts to them

Via the forum.

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 contact form.

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 pins are broken out so direct TTL drive is possible by bypassing the I2C port expander.

Via the forum.

Free O’Reilly webcast: Core Network Protocols


O’Reilly is offering a free webcast on “Core Network Protocols: Two techniques you need to know.” The 60 minute presentation by Bruce Hartpence will be live this Friday, October 14, 2011, at 1 PM PT.

In this webcast we’ll talk about address space, the purpose of the network mask and the reasons we manipulate network masks. As we go over subnetting and supernetting, listeners will be given two techniques to use when working through masking problems. As a part of the webcast, a simple and more complex problem will be completed.

Register now at O’Reilly.

#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 it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

You can get IR Toy v2 for $22.05, including world wide shipping.

Continue reading “#FreePCB via Twitter to 2 random RTs”

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 the contact form. Continue reading “7400 competition entry: Animated LED Christmas sign”

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 results could be achieved.

Via the forum.

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 (a handful of command strips have held two up next to T5s for over a year). Its fully dimmable and controllable.

Via the forum.

IR helicopter automatic altitude control

Amieres built a IR controlled Helicopter with Wiimote using USB IR Toy V1. A camera connected to the laptop tracks the helicopter. Using the USB IR Toy the laptop sends automatic altitude control signals. Setting attitude points is done with Wiimote’s up/down buttons, while nunchuk joystick is used for motion control.

Via the comments.

You can get IR Toy v2 for $22.05, including world wide shipping.