Topic: Electronics

The new items published under this topic are as follows.

Eeprom Programming Software unstable -- Jun 27, 2007

A while back I was actively developing my EasyTitle device, which controls a mini disk unit to allow quick editing of titles and table of contents. It is controlled by a PIC16F84 (1K program EEPROM, 68 bytes data RAM, 64 bytes data EEPROM ). To store all the keyboard codes and macros it uses a 24LC64 EEPROM (64k). I was using a PDIP PIC but a SMD EEPROM. The problem I was faced with is populating the 64K eeprom, as I had no means to program a surface mount chip (Only own a home made PIC programmer so wouldn't have been able to program a PDIP eeprom either).

After searching the net to find a way of populating an eeprom in stages, or indirectly from the PIC and finding no solutions, I decided to dive in and try it myself. So using a C compiler and various data sheets I finally came up with some source code which allowed me to program the PIC with a chunk of the data I wanted putting into the eeprom. It was tedious but eventually got the job done. I needed to re-program the PIC for every segment of data and increment the buffer count so the PIC knew where to place the data.

Not being able to find a similar utility on the web made me think that others might also find this useful, so I am now (finally) posting the code for anyone and everyone to use as they wish.

Feedback is greatly appreciated, together with ideas of improvements or additional features (although with it being such a small utility there is little room to implement more). If anyone finds this useful please send me a quick email so I know my work was not in vain.

Download can be found here (in the downloads section).

New found electronics skill - PCB making unstable -- Dec 10, 2006

No more stripboard for me... I have now 'mastered' the art of creating my own PCB's. Using a standard Laser printer and Ferric Chloride, I have produced my very first home made PCB.

The circuit used was from EasyTitle 2, a controller for minidisk players which emulates the remote control and allows you to quickly program all the minidisk titles from either a keyboard or PC Serial port. (Pretty nifty).
EasyTitle can be seen in it's entirity here

Using the supplied PCB layout I have 'seccessfully' (open to debate) created my own PCB board as can be seen in the gallery.

Homebrew portable USB battery charger! unstable -- Mar 22, 2006

I have just finished putting the final touches o­n an idea I had earlier today...

I am taking a flight to the states this weekend, and want to listen to MP3's o­n my Ipaq for as long as I can during the journey. This made me thing how long my ipaq batter will last when constantly playing MP3's, considering lately it has been dieing o­n me and i have had to restore all my files and settings (Pain in the arse!).

Anywhoo... I came up with the idea of having a square 9v batter in some sort of circuit that will power a USB socket, after all these devices o­nly use the 5v rail from a USB socket to charge and power. So I searched the internet a little and found a copule of people had already made such a device (Mainly for ipods, but they all do the same thing). People have been using Zener diodes to create a 5v supply from a 9v battery, or an array of 1.2v (AA, AAA...) batteries. Well seeing as I have been playing with electronics which need a regulated 5v supply lately, I know a little about the 5v regulator L7805. So, I have designed a circuit which uses the 7805 regulator, a capacitor (have lots of Tant caps laying about), and a few diodes for safety (of my ipaq). Put it all together o­n a test board and it all worked :). But the 7805 regulator wastes the extra power by converting it to heat... not much use for me and a bit crappy when relying o­n a small battery. So I decided to add a toggle switch, which I got from an ebay auction of "Various electronic components...". Together with the switch I needed an LED to show if the circuit was powered or not.

So after a quick trip to Maplin, I had all the bits needed to create my first practical project. Spent the rest of the night building the circuit and carving out the project box. Granted my Drimmel skills arent anything to boast about, but all in all I think I did a satisfactory job (It's not there for it's looks anyway). The o­nly annoying bit was the USB hole is not very square, and the socket is recessed into the box.

Well the glue is now drying, o­nce thats all set I will be giving it a field test to see how well it copes with charging my ipaq, and how long it lasts.

I think I wont be taking it to the states with me after all... I'm sure the airport security wont appreciate a little black box with a big red switch, LED and a few electronics being in my hand luggage... I doubt I would have time to explain myself and it just isnt worth the hassle (Those who know me will already know the hassle surrounding this trip to the states!!!).

I have, as always, posted some pics in the gallery. Link to them from here.

I will try and post circuit diagrams soon but it's pretty obvious where all the components go.

PIC Programmer complete and working! unstable -- Mar 19, 2006

I have finally finished my implementation of David Tait's classic programmer. It took me a while to plan it out o?nto a stripboard, but with the help of Lochmaster it all eventually took shape. Apart from having destroyed 2 PIC's :( Expencive hobby...

I am now looking forward to creating PIC software and making more LED's flash. There is o?ne project which is o?n my mind at the moment and should start to take shape in the next couple of weeks. I have already plotted out the circuit and created the stripboard layout, which will no doubt need refineing.
In the mean time here are the pics of my programmer.

In the downloads section you will find the stripboard layout for the programmer, together with a copy of the Linux port of Tait's programming software (Including all source code and build scripts).
Stripboard layout
Programming software (linux)

Another 2 elecy projects complete. unstable -- Mar 05, 2006

Granted they were bought as kits, but proved to be good experience with soldering and learning how the electronics work in them.

The first o­ne I did was a basic thermostat, ranging from 5c to 30c, turning o­n a relay which allows for a 24v 3A power output (Could come in handy for something).

The second o­ne is a 35 led (7 x 5) display for a scrolling message. The messages are programmable and it runs off either a 9v battery or power supply. The interesting thing about this kit is it takes a standard PIC microcontroller. So i bought it with the intention of replacing the PIC with o­ne of my own, complete with software to control the LED's in whichever way I feel the need. Unfortunately the company who make the kids declined my request for the source code, so I will be backwards engineering the chip from scratch and the schematic of the electronics.

Which leads me o­nto the next project in mind (when I can get all the components). I plan to build my own (Well, schematics off the net) PIC programmer. I am missing o­ne type of resistor which Maplin doesnt ever seem to stock :( So when I get that I will really start to make things flash in all sorts of patterns (Hopefully).

Pictures and movies can be found in the usual place.

My first electronics project is now up! unstable -- Mar 04, 2006

I have just uploaded the images for my first electronics projects to the gallery. I also put my first download up, the source code to control the parallel interfaced LED's.

Pictures can be found here.
Source code is here.

New found hobby unstable -- Mar 02, 2006

I've been experimenting lately with electronics, soldering and all that good stuff. Just finished building an interface with my Parallel port, controlling 8 LED's. I wrote a program in Linux which controls a "Knight Rider" display. I'll add the pictures, schematics and source code over the next couple of days.

I have a few more projects up my sleve so will keep the site updated with what i'm up to. In the mean time, I have uploaded links to various electronics websites which I have been using to learn all about the basics. Many a night has been spent playing with components and blowing up transistors :(