reader – Experimental Engineering

Posted on December 18, 2017 by The Engineer — Leave a comment

Stripboard Magic – A Call For Information

Some time ago I posted about an ancient piece of EDA software called Stripboard Magic, which was made by a small British company by the name of Ambyr. I have been hosting copies of this now long-dead software for some time, as it still seems to be in popular demand long after being abandoned by it’s creators. I have been contacted by a reader about the existence of Service Packs for this application, which neither of us have been able to locate.

From what I have been able to gather, Ambyr ceased trading around 1999-2000, after having sold the rights to distribute Stripboard Magic to Maplin Electronics. What I’m not certain of is the timeframe of these service packs appearing, or where they could originally be found, the Ambyr website apparently vanished about 6 months after Stripboard Magic was originally released, but they were presumably intended to make the application easier to use & less buggy.
Unfortunately the timeframe for the company’s existence was before the Wayback Machine started archiving the internet, and the only record they have of Ambyr is a domain holding page dating back to 2000.

If there are any readers who have copies of these service packs, or some information on where they can be found, or indeed any more information in general about this seemingly short-lived company, please drop a comment or E-Mail me directly through the Contact Page. Inquiring minds need to know 😉

73s, de 2E0GXE

Posted on December 31, 2011 by The Engineer — 1 Comment

Velleman MK179

This is the Velleman MK179 Proximity Card Reader, which is supplied in kit form. In the image above you can see the completed kit, the read coil is etched onto the black PCB on the left. Bringing a recognised card close to the coil operates the relay on the main PCB for a programmable amount of time.

Closeup of the main PCB, 12v DC input at top right. Left IC is an LM358 dual Op-Amp, the IC on the right is a PIC12F629 with Velleman’s custom firmware.
Logic power is supplied to the ICs & the oscillator from the LM7805 regulator at the top of the PCB. The relay is a standard 15A SPDT 12v coil relay, with the switch contacts broken out onto the screw terminals on the left.

As it is not provided with the kit, unlike other Velleman kits, here is the schematic for this.

Posted on December 21, 2011December 21, 2011 by The Engineer — Leave a comment

MSR605 3-Track Magnetic Stripe Writer

This unit was bought from eBay to experiment with Magnetic Stripe cards, for little money. This unit is capable of reading & writing all 3 tracks, & both Hi-Co & Lo-Co card types.
Interfaced to a PC through USB, this has a built in PL2303 USB-Serial IC & requires 3A at 9v DC to operate.
The 3 Indicator LEDs on the top of the unit can be toggled by the included software for Power/OK/Fault condition signalling.

Bottom of the unit with the model labels.

Closeup of the model label & serial number.

Here the bottom cover has been removed, showing the main PCB. The pair of large ICs bottom center interface with the magnetic heads. The IC above them has had the markings sanded off.

Closeup of the Prolific PL-2303 USB-Serial converter IC.

Here the connections to the R/W heads are visible, current limiting resistors at the left for the write head, a pair of signal relays, a pair of optoisolators & a LM7805 linear voltage regulator.

Here is the trio of indicator LEDs on a small sub-board.

The PCB has been removed from the main frame here, the only component visible is the rotary encoder.

The rotary encoder has a rubber wheel fitted, which reads the speed of the card as it is being swiped for writing. This allows the control logic to write the data to the stripe at the correct rate for the speed of the card. This allows the unit to write cards from 5-50 inches per second speed.
The Write head is directly behind the rubber pressure roller.

Here you can see the R/W head assembly. The write head is on the right, read on the left. When a card is written to, it immediately gets read by the second head for verification.

The drivers for this unit are also available here: Magcard Writer Drivers