Programming the spark core

Some of the following material is basic operating information for the Spark Core - for example, see the Spark Core documentation page on Getting Started. Nonetheless, there's other material here which can be a little harder to find. And it's definitely useful for using / programming / doing whatever with the Spark Core. Prerequisites [...]

By | 2017-02-04T18:43:54+00:00 Wednesday, 13 May 2015|Tech Note|0 Comments

Eclipse IDE set-up for Spark Core

The development system which the spark team have created is interesting, and certainly works for quick testing of the Spark Core one has just purchased. However it's really not a true / professional development environment... Therefore the question of: if a more serious environment is requried, how should one proceed? It's definitely possible! With a little [...]

By | 2017-02-04T18:43:35+00:00 Saturday, 9 May 2015|Tech Note|0 Comments

Transformers and IEC 61558

Upon starting to consider designing an isolation transformer, for potential listing as a product on this site, or at the very least for powering my latest project, I decided to review the standard IEC 61558 Safety of power transformers, power supplies, reactors and similar products. This is the relevant standard for transformers of all types [...]

By | 2017-02-04T18:39:28+00:00 Saturday, 9 May 2015|Tech Note|0 Comments

Nixie controller communications

This Tech Note details the communications protocol for the Nixie Controller Supply. The controller is based on an ATmega 328P uC with communications via a standard RS-232 style serial link (+3.3 V high / 0 V low), at a speed up to 115200 bps. Message format Top level description Byte Description SOH Start of [...]

By | 2017-02-04T19:32:50+00:00 Thursday, 23 April 2015|Tech Note|0 Comments

Inrush current limiter

In my last posting, relating to the design of an isolated power supply - Designing an isolation power supply - I identified that there could be an inrush current problem... (There most definitely was! The 2 A slow blow fuses didn't stand a chance with the 300 VA toroidal transformer having a primary winding DC resistance of 3.92 [...]

By | 2017-02-04T21:51:42+00:00 Thursday, 24 July 2014|Tech Note|0 Comments

Isolation supply design

One piece of equipment that the lab has been lacking is an isolation transformer. Such a transformer is useful for testing circuits/devices such that they're "isolated", as the name of course suggests. A good overview of why one might do / needs to do this is provided on Dave Jones' EEVBlog: EEVblog #279 – How NOT [...]

By | 2017-02-04T22:08:36+00:00 Wednesday, 23 July 2014|Tech Note|0 Comments

Bidirectional logic level shifting

Level shifting - changing the voltage of a signal from one circuit to suit the voltage of a second circuit - is not particularly new... Witness the very common MAX232 IC from Maxim, which provides unidirectional conversion of signal lines from true RS-232 voltages to TTL voltages. A similar requirement exists for interfacing 5 V logic [...]

By | 2017-02-04T22:28:18+00:00 Saturday, 19 April 2014|Tech Note|0 Comments

50 ohm TTL line driver

This Tech Note describes the 50 ohm TTL line driver kit (and PCB). The design for this came from a need to interface a 1 pps (1 Hz) TTL reference signal from a GPS Disciplined Oscillator to a 50 ohm output. The 50 ohm output signal being connected to a signal generator, frequency counter, etc. Hardware The [...]

By | 2017-02-04T22:17:38+00:00 Saturday, 19 April 2014|Tech Note|0 Comments

Arduino SRAM expansion

This Tech Note describes the Arduino Mega SRAM expansion shield kit (and PCB). The design for this shield comes from Andy Brown - - where he has detailed all the relevant information. So, this Tech Note is not a full description, rather just the relevant links and additional information. (Refer to Andy's website for all the details!) Update [...]

By | 2017-04-23T10:09:52+00:00 Saturday, 19 April 2014|Tech Note|1 Comment