Stephen Coates' Homepage


stevecoates.net

Updated: 8th April 2016


Home Page

About Me

Contact Me


Amiga 1200T

AvoMeter

CRT Fan Club

Electronic DC Load

Backlight Hacking:

BT Decor 2200

Mastech MS8218

Walkman Repair

(D)SLR Focusing Screens

Photo Printing

Cherry Pi Project

Motor Cars & Safety

Stephen's Flickr Page

Crap Customer Service

8th April 2016 - Cherry Pi

A while back, I started a project to mount a Raspberry Pi computer in a Cherry G80-3000 keyboard (Amiga/BBC Style). Here is the result.

The Cherry Pi in Action

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8th April 2016 - A quick comparison of Lightjet prints vs Inkjet prints

In this post I demonstrate some of the differences between these two printing technologies.

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13th July 2015 - SLR/DSLR Focusing Screen Experiments

Many modern low end SLR cameras have terrible focusing screens. If you have seen one of the high quality focusing screens found in manual focus film cameras, you will probably come to hate the focusing screens in modern auto-focus cameras.

I attempted to bodge a higher quality focusing screen into my EOS 500D, with varying success.

Read more...

Left: A typical DSLR viewfinder, with no focusing aids. Right: A high quality focusing screen with a cross split prism for high end cameras.



July 2015 - More Road Safety

Certainly journeys in Rotherham have now become more dangerous and more time consuming due to the council's unnecessary closure of a subway. Here's a letter which I wrote to the local paper. At least one other person wrote in to the paper as well.

 

       


6th March 2015 - Car Parking

Many walkers, such as myself, will tell you that motor cars parked on the pavement are a nuisance. Here is a Flickr page which shows some photos of illegal parking in my area. 

Meanwhile, many lazy sods avoid some places because 'there's no parking'. I have never really needed parking anywhere, so I'm surprised many people make such a fuss about it.

Here is a letter I had published in my local newspaper recently.

Hopefully it will inspire some people to use more sustainable transport.


6th March 2015 - Customer Service Updates

The Crap Customer Service pages have been updated to feature Northern Rail, and a couple of response letters.


28th October 2014 - New Series! - Crap Customer Service

After getting fed up of being treated poorly by many organisations, I decided it was time to name and shame them on the internet. Over the coming weeks I will be publishing various complaints here on this website, and where applicable, any responses received from the organisation concerned.

Feel free to get in touch if you have similar experiences with the organisations listed.

First up in this series is Manchester Airport, and the security bloke who lacked fluency in English. I'm getting rather fed up of people working in England who lack fluency in our language.

Read More...


22nd June 2014 - Sony Walkman Repair & Maintenance

My old Sony Walkman has suffered lots of abuse over the years, but I manage to keep it working. Find out how on my new Walkman page.



March 2014 - Motor Cars & Safety

I wrote a short article about the safety and environmental impacts of motor cars.  As someone whose health issues are somewhat a consequence of this, it is something I feel strongly about. Read the article here: Motor Cars & Safety.

I urge everyone to do their best to consider safer and more environmentally friendly transport.

An important note on noise pollution: I don't mention noise pollution much in this short article, because I focus more on safety in terms of 'car crashes', but noise pollution is a major issue which so few people seem to understand. Cars create noise at such a level, that if the road were a typical work place, we would be required to wear hearing protection. The noise can be very distressing, as well as irritating. I live near a busy road, and can not keep my window open in summer because of it. 

I'd be willing to hear from other people who suffer from motor car related noise problems. If you would like to get in touch, please visit the Contact Me page.



March 2014 - EEWeb Site of the Day

My site is due to be the Site of the Day on EEWeb next month in April. EEWeb is on online community for electrical and electronic engineering. It features forums, news, jobs, featured engineer, featured website, and a comic :).

Check it out here: http://www.eeweb.com/websites/stevecoates



18th January 2014 - More Updates

New Look 

Firstly, you may have noticed the site's new look. It has been modernised, and looks a bit cleaner. I'm updating all the existing pages with the new look, and all new pages will get it. It utilises some CSS, which simplifies the code. I may eventually update it to include some PHP, but that's something for the future, at the moment, I'm focusing on the content.

Backlighting Guides

After being frustrated with the backlight on my Mastech MS8218 multimeter, I decided to improve it. Check it out here. I also made a backlight for a telephone's LCD, which didn't already have a backlight. I documented that as well (click here). The page shows how you can make a simple but effective LED backlight to place behind your LCD.

Backlit telephone LCD


Lincs Amiga Group

After a break of about 3 years, I've started attending the Lincolnshire Amiga Group (LAG) again. At LAG meetings, a group of Amiga enthusiasts from across the country meet in Lincoln to play with Amiga computers. I'm finally getting my Amiga 1200 running again. I even managed to set up wireless networking!

Check out the official website at http://lincsamiga.org.uk/ and see some of my photographs at Flickr.



12th December 2013 - Project Updates

Various electronic projects of mine have been mentioned around the internet lately. Here they are on this site.

Electronic Constant Current DC Load

A constant current DC load is useful for power supply and battery testing. Basically, you set a current, and it will try to draw only that amount of current, regardless of the input voltage. As I'm building a bench PSU, this is a useful tool to have, and a very simple one to build. I have documented the circuit design and build on the following page: http://stevecoates.net/cc_load/.

This image shows the fully functional stripboard prototype:

 

Bench Power Supply & SOIC8 fun

I've been experimenting with a variety of bench power supply designs lately. My current design is based on an LM723 chip, with a 2N3055 as a series pass transistor. It features adjustable voltage (between about 2.5 -- 25V), and adjustable current limiting (between about 30mA and 1A). It will have a panel voltmeter and ammeter. I was pondering using the traditional ICL7107/7106 IC for these, but I decided to do it using an Arduino, as an excuse to learn some Arduino programming. Current monitoring is achieved by a MAX4172 IC. This is a surface mount IC, and required a bit of fiddling to use on a breadboard.

(Update: I decided to buy some small ready made panel meters instead)

Eventually, the power supply circuit will be retrofitted into the 'Datatext' case which can be seen in the photo.

I'll publish full details eventually, but in the mean time, here is the circuit diagram (subject to modifications) and some photos.

Breadboard:

Ghetto SOIC8 adapter:



27th July 2012 - Test Equipment! Thurlby 1503 Multimeter Mods

A couple of years ago, I got an old Thurlby 1503 digital multimeter off ebay for about £10. This is a "four and three quarter digit" multimeter, which gives it a nice bit of precision.

It has a small LCD display which updates slowly and is hard to read. So, I'm modding it to have a larger, brighter, LED display. Here it is with the original LCD display, next to the AvoMeter:

A Black and White photograph of the Thurlby 1503 digital multimeter. Shown in comparison to a Model 9 AvoMeter.

Hitachi V-222 20MHz Oscilloscope

I've wanted an oscilloscope for years. I finally got this one. It's a basic 20MHz analogue scope. Got it off ebay for about £70. Works nicely. Here's a photo of it showing the waveform from a voltmeter IC's internal oscillator:

Photograph of a Hitachi V-222 20MHz Oscilloscope



3rd December 2009 - Pictures

Amiga 1200T

2012 Update: The Amiga 1200 Tower is now working much better.

I have uploaded a few pictures of my Amiga 1200T. They aren't very good though. The Amiga is located in the loft where only limited space and light is available. The photo at the side shows the system working with a Microvitec 1438S monitor.

Unfortunately though, this system isn't very reliable. Last time I used it, the graphics from the VooDoo were rather weird. But sometimes, it wouldn't work at all. I wonder if there is a bad connection somewhere between the VooDoo and the Amiga.

See the rest of the pictures here.

Parallel Port based Analogue to Digital converter

To the left is a screenshot of the programme I wrote to monitor up to all seven inputs from a Maxim MAX118 8 bit ADC. The screenshot is showing just Channels 1, 3 and 7 in use.

  • It can measure voltages from 0V to 5V.

  • With an LM335 temperature sensor (together with an op-amp interface circuit), temperatures of -20°C to 105°C can be measured.

  • With an LM35DZ sensor (again, with an op-amp interface circuit), temperatures between 0°C and 100°C can be measured.

The circuit interfaces to a PC with a 'Standard' (unidirectional) parallel port. This means it *should* work on an original IBM PC. However, I was unable to test this. The programme was written in QuickBasic 7 and runs in MS-DOS or Windows 95/98.

The circuit diagram shows how the MAX118 is interfaced to the parallel port. The 74LS157 is used to convert the 8 bit output from the ADC into two 4 bit nibbles.

I will put some more complete details on the site eventually, but do to accuracy issues I had with the MAX118, I am currently trying to make a similar system, but using the cheaper and slower ADC0808. The ADC0808 should be just as suitable despite its slower speeds, as high speeds are not required for measurements such as temperature.

I also hope to try and make interface such a device to the Amiga computer as well as the PC.


21st July 2009 - Power Tower

At LAG13 last Saturday, I got a Power Tower to put my Amiga 1200 in. Well, only the Blizzard 1230-IV, Mediator, HD and cards, as the tower already had a motherboard. Pictures and details coming soon. In the meantime, check out the topic about it on the Classicamiga forums and my Flickr page (see below).

Also, we have some new members at the CRT Fan Club :).


2nd July 2009 - I can't really think of a title

I haven't put much on this website. I made a brief update about the convergence problems on my Sony monitor.

I have finished my college project of building an Analogue to Digital converter for the PC's parallel port. I will post some information and pictures of this soon.

I am also going to make a page about getting the VooDoo 3000 graphics card to work on an Amiga 1200 with a Mediator PCI. I expect this was simple for some people, but me and the guys at LAG had a bit of difficulty. It is all working now though. Just got to sort out the sound and network card, and hopefully get it in a tower.

Got a few photos of LAG meetings and of Lincoln which I will put online sometime. In the meantime some lower resolution versions can be found on my Flickr page: http://www.flickr.com/photos/36651585@N04/

Older Updates


Cool websites I recommend you should check out:

ClassicAmiga - Your Guide to everything Amiga

Amiga Computing and Retro Gaming

Link to Dave Jones EEVBlog

Electronics Video Blog

Electronics, Solar Power and Metrology

Old-School Game Blog

Other links:

The Aussie Space Time Traveller

E-Maculation - Macintosh Emulation

EEWeb - Electrical Engineering Community