Welcome to the Cumbria & Scottish Borders Area Group Forum

You may have noticed the new Contact Us tab at the top of the page. Whilst you are encouraged to comment on any blog post with any opinion, suggestions, help or guidance that others might benefit from these should be relevant to the post. If you want to contact us about any other subject, or would like to write something yourself on a subject that interests you for example model building, designing layouts, baseboards or any projects you are working on - the Contact Us page is now available and working. Simply fill the Contact form and press the submit button.  Author rights can only be given to MERG members and it would be helpful to provide this when applying. If you have found something or fixed something don't hesitate to share it with the group.  If you are having problems with anything and looking for a bit of help - just ask Andy R 

The first Beginner's session of JALSIG (Just Another Language Special Interest Group) took place last night with around nineteen participants. JAL offers a much easier way to program PICs which you will find in many MERG circuits. As you can see from the image of a PIC 12F675 as used on many Pocket Money Projects ( above ), some of the pins have multiple functions and it can take quite a bit of time to work out what bits need to be set to achieve your requirements. JAL contains configuration files for every PIC family making this process of selection much easier. If you want to get a feel of the discussion, you can now watch it in the MERG TV area, but to save searching here is a direct link  BEGINNERS ONE It's not everyone's cup of tea, but if you want to find out how the Easypoint circuit really works..(as an example) this is where you can start Andy R

Sunday's Zoom meeting had our largest audience so far with 19 members attending from various parts of the country. Alan Geekie gave us an excellent and well received presentation on 3D printing that included FDM (Fused Deposition Modeling) and SLA (Stereolithography apparatus) types He first showed how we can source "things to print" using sites like Thingiverse. His own filament printer was the Prusa i3 Mk 3S which is available either as a kit (£699) or pre-assembled (£899) and features a self leveling bed. It also benefited from an additional multi material upgrade kit and he demonstrated the start up sequence of leveling, homing, clearing remaining filament from the hot end and then beginning the print.  The process of slicing where a 3d object drawing file (.stl) is broken up into the x,y,z drawing coordinates for each individual layer was also explained. Alan then moved on to resin printers using another Prusa model, the SL1 and its associated curing and washing mach...

If you want to program your own PICs or upgrade them to the latest version, a PIC programmer is an essential tool This one can plug directly into the included Zero Insertion Force (ZIF) socket but an additional pin to pin extension cable is also provided. The PIC chip needs to be removed from the board and placed in the correct location on the ZIF socket. It supports 8, 14, 18 and 20 pin devices. The jumpers need to configured specific to the device in use. On some PCBs an ICSP (In Circuit Serial Programming) header is provided. This allows the Chip to be programmed on the board and is a common feature on some of the MERG Kits. The cable provided above is NOT suitable for ICSP use. A short cable needs to be made up specifically for onboard programming. The cable should not exceed 6 inches ( 150 mm ) in length. Greater lengths can be problematic, particularly for K type PICs Andy R

For those using or thinking about using Digital Command Control ( DCC) on their layouts, a MERG kit CANCMD2 is available. At today's meeting of the Virtual Area Group, Martin Perry described in detail how this circuit worked. All DCC controllers work to an agreed NMRA standard  , which sets out how the required  control data is encoded and superimposed on the track power lines.  The original Rev A board ,CANCMD1 which ran off an ac supply was described and details given on how this could be modified to run off the safer dc power blocks that we are familiar with. The newer improved CANCMD2  board  which requires a 15 Volt dc supply, has additional leds to indicate when the board is powered up and also to show when track output is available.  Other improvements are in the design of the power supplies and in the PIC timing now working from an 8 MHz crystal rather than the previous less reliable resonator. A link will either pass power to the tracks using a CMO...

The JAL (Just Another Language) online course is just about to start.  At the inaugural meeting of the JAL Special Interest Group last week, a few suggestions were made for suitable PIC development boards. The 50 mm x 50 mm  board above is from Fraser Smith and is the same one featured in his automatic signals articles featured in the March and June 2020 Journals.  At £1.40 for one and only £1.80 for two that include the 20 pin DIP socket,  my choice was clear. The advantage of this board is that it can be used for 8, 14 or 20 pin PICs, The second potential board is designed by Alan Turner. It is slightly smaller at 50 mm x 33 mm but can only support 8 pin PICs. Given that most of the pocket money kits produced by Davy Dick utilise the 8 pin  16F765 chip, perhaps this will not be an issue, The board is available in two versions, differing only in the power capabilities of the onboard  5 Volt regulator. ( 78L05 or 7805 ) This board can be used to build some ...

Another excellent Zoom Meeting this afternoon run by the West of Scotland Area Group. Over forty people joined the meeting. Davy Dick first showed us a  commercially available multi function stepper motor driver module. Operating between 5 and 12 Volts it works on both four and five wire motors. Four different operating modes are available selected by jumper. There are two push button switches on the board that have different effects depending on the selected mode. These switches could be removed and replaced by external ones.  In addition a 4pin header allows further  connection to switches or sensors. The large pot controls the speed of the motor and the smaller one, the length of travel when that mode has been selected.  This is a good board for simple end to end travel ( shuttles) and costs less than £5 on eBay (other suppliers are available).  Davy demonstrated it working driving a NEMA-17 motor with  lead-screw and limit switches and then with the muc...

I have just ordered a couple of PIC development boards from Fraser Smith in preparation for the JAL (Just Another Language) Zoom course starting soon.  I ordered some 11 pin 3.5mm pitch terminal blocks from RS which are priced at 63 pence each. This is only 2 pence more than the four pin. As you can see they break up to form 3 off 3 pin  and 1 off 2 pin connector. These connectors fit the EzyBus input module ( 3+3+2) for each 8 pin row with a 3 pin left for other projects.   If you are interested in finding out about PICs and PIC programming, there is still time to sign up for the JAL Special Interest Group. See previous postings for details Andy R

Due to the density on the LM317 module circuit board, the fitting of securing screws through the two available 3.1 mm holes is potentially problematic. There is also a potential for shorting on the soldered pins under the board.  I designed a holder in Sketchup that resolves both problems. The hollow area provides clearance for the soldered pins and two holes are provided for securing to a baseboard. The module simply clips on to the two plastic pins. If anyone is interested, I can send you the .skp file and/ or the .stl file if you have a 3d printer. Here is an image of the completed unit alongside my almost completed freight yard. Might be able to print a few for those without printers Andy R

The LM317 is a very useful device for producing specific voltages for your layout.   You can buy it as a 3 pin device and by adding a few capacitors and two resistors you can set the output voltage to between 1.25 volts below the incoming supply voltage and 1.25 volts higher than ground. The ratio of the resistors determine the output voltage based on the following formula.  V out = 1.25V x { 1 + R2 / R1 } The Output voltage is also affected to a small extent by the current flow in the adjust line. Resistors are normally 5% tolerance so producing an exact fixed voltage can be problematic. It's for this  reason that one of the resistors is normally made a variable one to enable fine tuning. You can make these yourself on a piece of strip-board,  but given the costs involved it is much cheaper to obtain them as a  built module . I bought some warm white LED's which theoretically operate in the 3.0 Volt to 3.2 Volt range. Using the LM317 module I could set the vol...

You may or may not be aware that there are some Special Interest Groups ( SIG's) being created within MERG. It is easy to get involved by going to the relevant page on the website. I've put the link here  for your convenience. I have always been fascinated with what is happening inside those Pocket Money Kits and the JAL Group (Just Another Language) will show how this PIC chips get programmed. The Inaugural Meeting took place tonight with beginners, intermediate and experts attending. In future there will be fortnightly meetings. One of the meetings will be in the form of a beginners course and two weeks later a general meeting. Everyone is free to join both. If your interested in finding out about JAL and PIC Programming there is a new section in the Knowledgebase section of the MERG website you can have a look at. https://merg.org.uk/merg_wiki/doku.php?id=sig:jalsig You can find out in the Useful Equipment section what you will need to participate. Cheers Andy R

Thanks to everyone who attended Sunday's Zoom meeting. There were five regular Hawick Men's shed attendees and a further two from other areas. Nice to see you all. Martin Pearson sent me his print file for a solder reel holder that conveniently fits on the PCB holder that Keith Torrington showed us during the meeting.  It's a very useful and robust tool for holding the PCB firmly while assembling your electronic project. I bought mine years ago and they are much better than the traditional " extra hands" type that use crocodile clips to potentially damage your board.  https://amzn.to/2OmJPww  is a link to the Amazon Site. I had to slightly modify Martin's file by reducing the external diameter from 20 mm to 19 mm so it would fit my particular solder reel. Thanks for sharing Martin. For those interested in 3D printing, we are hoping to confirm that Alan Geekie will be available to give a presentation on that subject at our next Zoom meeting. Lookout for your in...

Hi All Just a reminder that the next zoom meeting is on Sunday 12th July at 2pm. This is a coffee and chat meeting . Keith will open the meeting at 1.45 pm so members can get logged on. See you there Andy R

Welcome to the site which has been set up for all members of the Scottish Borders Group of MERG.  As you know, I have been working on various Arduino projects recently including the station and cafe displays.  There are many resources available online when you come across a problem but a good reference book which explains how things work is essential.  I have tried a few and found the following book the best so far. It is well written and laid out logically for the beginner to be able to develop new skills. The structure of the Chapters makes it easy to find the relevant section.   By clicking on the link below you will be able to look inside and see for yourself. https://amzn.to /38HfrWW If you decide to purchase through this link  you should be aware that I will receive a small commission on any sales generated which will help to finance further projects Andy R