Digital trainers integrate a breadboard with simple I/O and they are a great tool to learn digital circuits. DIGILAB-R is a vintage style digital trainer designed to be compatible with the Scuola Radio Elettra DIGILAB. It can be used to perform all the experiments in the Digital Electronics distance learning course that was popular in the 80's.
Many MCU applications use electro-mechanical relays to control AC loads. While this is an excellent solution for occasionally turning on/off a load, it is not suited for frequent switching or PWM applications. SSR1/A is an opto-coupled solid state relay that can control two AC loads in a arduino shield form factor.
While working with Arduino in industrial applications it's often useful to have a isolated voltages available. Depending on the circuit configuration, ISO02 can generate galvanically isolated unipolar and symmetric voltages from the 5V Arduino power. The circuit is based on a basic push pull configuration and uses an easy to obtain off the shelf transformer.
Like many other hobbyist we have always been fascinated by radioactivity and the sensors to detect it. Geiger-Müller tubes are a common and relatively inexpensive way to measure radiation. GRAD is a complete solution for radiation counting in an Arduino shield form factor. Its main features are dual tube support to increase sensitivity and very low power consumption.
A new version of this project is available here
The Apple II SCSI card from 1986 was one of the first interface cards to attach a Hard Disk Drive to the Apple II line of computers. A2SCSI is a clone of the last revision (rev.C) of the card with a few enhancements to improve compatibility with modern SCSI drives.
The Tandy TRS-80 model 100/102 and 200 provide a ROM socket to add built in programs to the machine. To make inserting and replacing the ROM more user friendly the designers choose to use a custom chip socket (Molex series 78805) with 700mils pitch. The Molex carriers that mate with the sockets have been out of production for many years and are nowadays impossible to obtain.
The apple IIgs, like many computers from the 80's and early 90's, has a analog RGB output at a 15KHz horizontal frequency (same as NTSC/PAL). The majority of modern monitors and TVs will not sync to anything below 31.5KHz on their VGA input. If you have a TV with a SCART connector it is possible to wire the RGB directly to the TV. Most TVs in USA, however, use the YPbPr component instead of SCART making a direct connection not possible.
Being nostalgic for the birth of laptop computers we recently acquired an Olivetti M10. The M10, like many of the KC-85 derivatives like the Tandy TRS-80 Model 100 and the NEC PC8201A, uses custom modules for their system RAM. These modules contained four 2Kx8 SMD SRAMs mounted on a ceramic substrate with a non standard DIP footprint. Needless to say, these modules have become increasingly hard to find.
The Minipro TL866 is very popular among hobbyist because of its low price and ease of use. Its list of supported chips is however somewhat limited compared to more expensive professional programmers. The E2R16v2 adapter adds support for the ROM pinout compatible EPROM of the 27C400/800/160 and C322 series.