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Here’s a FREE graphics program to make your PICAXE Electronic Bread Board Layout Emulator Imagine being able to produce a professional quality diagram such as the one shown above to show how a circuit was laid out on a breadboard. You can – and the software to do it is FREE! And despite the name, it’s not limited to PICAXE circuits, it’s universal! W e shouldn’t have to tell you how incredibly ver- but to make it nice and simple for anyone else (magazine satile breadboards (also known as “Protoboards” editors included!) to understand. are when it comes to designing, developing and Professionals are one thing but newcomers hesitantly troubleshooting electronics circuits. following circuits “paint by number” style may especially We often use them here at SILICON CHIP when developing benefit from lucid layouts. projects for the magazine and we encourage readers of all Typically these will be students learning about practical levels to use these quite cheap and widely-available aids. electronics (often under tight syllabus and time constraints), But what if your design doesn’t quite work as intended when very clear circuit layouts may be appreciated as a and you start looking for help – perhaps on-line. confidence booster. You’re going to need to transfer the design onto paper, In spite of today’s ease of digital imaging, pictorial reor at least into a format that someone else can easily read quests may however meet with some reluctance, perhaps and hopefully trouble-shoot. due to the untidy nature of hook-up wiring. Well – let’s Or perhaps it does work exactly as you’d hoped and you face it – often it IS messy! want to share your brilliant design with the world (maybe Even some old hands are wary about posting public even get it published in photos of their new super SILICON CHIP?) It’s essenOriginal “Virtual Breadboard” software: Ray Wilson duper layout, as they tial that a clear, lucid repfeel the wiring may be resentation is presented, PEBBLE development and article author: Wayne Geary scorned. Additional material: Stan Swan and Ross Tester not only to avoid errors At least one’s soldering 64  Silicon Chip siliconchip.com.au breadboarding easy . . . will not be criticised with solder-less breadboards! Although long established for versatile and rapid prototyping, these breadboards still take time to populate, with associated wire stripping and neat component layouts requiring a focused mind and steady hand. When wrangling components under pressure, perhaps as a stressed teacher organising course work or a student Going way back, meeting project deadlines, confusing this is a valve “crystal set” radio receiver. Many, many “rat’s nest” layouts may result. millions of radio and electronics Well, now there’s a way to produce enthusiasts have “cut their teeth” breadsuperb breadboard layouts in just a few boarding circuits just like this one or more recently, minutes – thanks to new JavaScript- with diode-based crystal sets! based software known as PEBBLE (PICAXE Electronic Bread Board Layout Emulator). This totally free program has appeal for newcom- and straighten the leads. A 1964 patent describes a wooden ers, old hands in the electronics field and even (or perhaps plate breadboard with mounted springs and other facilities. especially?) school electronic courses. Some early commercial electronic kit “boards” had a While the title includes the word “PICAXE”, it is stressed cardboard or plastic base with a series of springs arranged that the program is equally useful in general and digital in a matrix and the component leads were slid between electronic fields. Besides, “PEBBLE” has a much better ring the turns of the springs to secure them mechanically and to it than does “EBBLE”! electrically. These were still readily available in the 1980s There’s something compulsive about a neat looking and 90s; indeed it is still possible to buy such things today breadboard circuit that makes you want to go and build it. as part of multi-circuit electronics project kits. Compared with gathering the tools to wrestle with a lashed All this brings us to today’s classic, usually white or up soldered version, a lucid “birds eye view” breadboard bone-coloured plastic pluggable breadboard, as illustrated layout tends to encourage even the most hesitant assem- in this article. It was designed by Ronald J Portugal of EI blers. Instruments Inc. in 1971. The author purchased his first breadboard of this type in the late 1970’s having 30 rows Breadboards and their advantages of two groups of five holes and two rows of holes along “Breadboards” got their name from the way electron- each side for power rails. ics circuits were often lashed together on a piece of scrap The breadboard has a matrix of holes in the top, one tenth softwood, sometimes using small brass nails hammered of an inch apart (most multi-pin components are based on into the board as anchor/solder points. the Imperial measurement). Inside there are sprung metal Occasionally, beginners misunderstood the term and strips which electrically link groups of holes together in actually pinched mum’s good breadboard to hammer nails a known pattern. into and connect components – with predictable (and often When a component lead is pushed into one of the holes painful!) results. it slides between the copper fingers at each side of the hole Some early breadboards in the days of vacuum tube cir- which makes electrical contact. When a second component cuits (valves) used point-to-point wiring and later circuits lead is pushed into another hole in the same group then used tag strips mounted to the board, onto which compo- the two component leads make electrical contact. A typinents were soldered to the various tags. cally breadboard has one or two rows of holes down each Other examples had an insulating sheet with a series side that are generally used for the power supply rails. of tags or pins along the two long sides between which Between these two sets of power supply rails are rows components were soldered. of holes, normally arranged as two groups of five with a The downside of these early breadboards was that the re- central gap. The gap is two holes wide and suits most of use of components could be difficult due to need to desolder the DIP integrated circuits. As discussed in this article, here’s a five-way tagstrip . . . siliconchip.com.au . . . and two types of tagboards. All three of these were very popular methods of construction before PC boards became the more preferred method. September 2009  65 Again, back in the pre-PC board days, construction methods were usually either point-to-point (ie, from component to component where possible) but also involved the use of tagstrips to also mount components on. One prime advantage of the breadboard is that no soldering is required, which removes the safety risk (eg, of burns). Other advantages are that components can quickly be changed for circuit adjustment, there is no damage from soldering and desoldering so that components can be re-used many times over and time to develop or change a circuit is faster than a soldered board. As such, a circuit can be constructed and tested quickly to prove operation before moving to more permanent prototyping boards and ultimately designing and assembling final project circuits on custom-designed printed circuit boards. For these reasons, many hobbyists, electronics labs and in particular schools make use of breadboards. In the school environment, safety with hot soldering irons and the short time available to perform an electronics lab session make the use of breadboards virtually paramount. What is (and is not!) PEBBLE? PEBBLE is a software program that gives a visual or pictorial simulation of a circuit layout on a protoboard. It does not design the circuit for you, nor does it show any errors you have made. If, for example, you connect the battery the wrong way around and your errors are copied by those who then build the circuit, the smoke will escape just the same! It enables the user to show the layout of a circuit being assembled on a breadboard or protoboard. The visual representation includes the wiring and a range of discrete electronic components, integrated circuits and even a range of off-board components. It was originally intended as an aid to producing PICAXE circuits, therefore PEBBLE features an extensive range of PICAXE chips and many of the more frequent support chips, all of which have the pin designations shown against each pin. But it’s grown into much more than a PICAXE aid. It’s now universal and can be used with virtually any breadboard/ protoboard circuit. There is a range of general-purpose DIP format IC chip layouts for those occasions when the chip Above is the opening screen of PEBBLE. The 23-way board is the default but you can change it as you wish. At right is the component menu – just drag and drop those required. 66  Silicon Chip siliconchip.com.au you are working with is not Included is a range of comincluded in the default packponents suited to the PICAXE age library of components. microcontroller community. PEBBLE does not incorAfter some months of hard porate any animation. If you work including a number of must have animation, there preliminary releases for othare several commercially ers to trial, Version 2.2 was available packages which released. incorporate animation and Now in version 2.4 (even if operational emulation. our screen shots show 2.3!), it Commercial programs inincorporates some recommenclude PICAXE VSM by Rev dations from members of the Ed for £50, Yenka ElectronPICAXE community includics by Yenka.com (Crocodile ing well respected educator technology) at $825 for a small and frequent S ILICON C HIP school site license), Virtual contributor Stan Swan. Breadboard by Virtualbread- Here’s how the component holes are connected together The original package ocboard.com, and the National internally in a typical breadboard/protoboard. Others may cupied 354 Kbytes of disk Instruments Multisim “Elec- only have one supply rail top and bottom. space and contained a total tronic Workbench” for $909 of 54 files. The program infor a single user for 1 year or corporated a single 23 row $27225 for a college license. Some of these commercial breadboard as a working “surface” with single orientation products may have a free limited version available for general 8, 14 and 16-pin DIP IC packages, a single size of trial purposes. resistor, a single type of capacitor, a single colour horizontal PEBBLE is not a trial – for your money ($0.00) you get format only LED, a single size and type diode package, and the complete working version. Schools will be lining up wires that could only be aligned to the breadboard holes. for this one! While Ray Wilson has subsequently incorporated some of the changes started by the Author (for example 38-row Origins of PEBBLE bread boards) and a few of the simple suggestions put forA US audio enthusiast by the name of Ray Wilson cre- ward by PICAXE community members, Ray, being primarily ated a program called Virtual Breadboard to aid him and analog-oriented was happy to leave development into the his followers in the analog and audio fields. This program digital and PICAXE realms to an enthusiast in that field. had a rather limited repertoire of components and wires. PEBBLE at Version 2.4 occupies 3.6MB of disk space and Earlier this year, the author contacted Ray Wilson for contains a total of 461 files. permission to take the core from the Virtual Breadboard What PEBBLE includes program and create a program package aimed at the general and digital electronics enthusiast. PEBBLE has an extensive repertoire of components, Dragging the DIP IC image to the breadboard, then (right click) editing to insert label text and selecting the “Picaxe 14M” to display the IC with pin identification” siliconchip.com.au Composite image showing the editing features for various types of light emitting diodes (at the left) and signal/power diodes (at the right). September 2009  67 including: • approximately 40 breadboard permutations, • numerous DIP integrated circuits in 8 pin sizes, • resistors in four physical sizes, • capacitors in four types with each in three sizes, • LEDs in five colours and four orientations, • diodes in two packages with three sizes, • transistors in two package formats and four orientations. • terminal strips in various formats including some generic SIL plug-in modules which use terminals strips, • four switch formats, • and extensive range of other components including LDR’s, thermistors, resonators, piezo sounders, potentiometers, trimpots, LCD modules, various battery combinations, keypads, relays and assorted motors including a servo-motor. Breadboards Breadboards are provided in 23, 30, 38, 44 and 50-hole lengths. In addition to the ubiquitous white breadboard there are several in alternative colours such as some light blue variants which provide better contrast for many components. There are boards available in formats with single and dual power rail per side. One breadboard variant is based upon the complete DSE H-6505 prototyping board, a second is based on the DSE H-6513 fibreglass prototyping board while a third is based upon the Kiwi Patch Board (KPB). While not exactly a breadboard in the visible sense, there is a separate off-board area provided below the displayed breadboard with a similar but invisible, hole spacing for the positioning of typical related breadboard components such as toggle switches, LCD modules, motors and batteries. The invisible hole spacings are the same as the visible breadboard area. There is also a specialised version of a 23-row white breadboard with coloured polarity indication for the power Flexible wire editing allows colour selection, wire positioning and compact grouping with the offset wire feature. 68  Silicon Chip rails, a small off-board patch area at the right end having visible holes/connections points and a pre-wired battery box (including three AA cells) for a quick-start format for learners and school applications where time in getting newcomers under way is critical. DIP IC packages From the humble beginnings for DIP IC packages with just a single orientation in 8, 14 and 16 pins, PEBBLE has an extensive range providing 27 DIP packages. These include 4, 6, 8, 14, 16, 18, 20, 22, 24, 28 and 40pin formats and can be orientated with pin 1 to the bottom left or the top right. Each size is available as a general DIP package for use when a specific IC is not available. A full range of PICAXE chips in the 8 to 40-pin range is provided. The ubiquitous 555 timer IC is also included. Frequent support chips such as RTC’s (DS1307 and similar), EEPROM (24LC series), i2c Expanders (MCP23017), Darlington transistor packages (ULN2803), H-driver package (L293D), various other packages such as the 74HC595 shift register and 4000 series IC’s for counters and BCD to 7-segment drivers. Finally there is a typical 7-segment display (FND500 series). Discrete components: Resistors are available in four physical sizes and two orientations (horizontal and vertical). The colour bands on the resistors are active and change to reflect the selected resistance value. Capacitors are provided in polyester “greencap”, radial and single-ended electrolytics and tantalum packages. Capacitors can be oriented in four directions to account for polarity and three sizes for each package. Capacitance value can be included as a notation displayed across the body of the component image. Diodes are provided in both glass (orange colour) and plastic (black colour), each in four orientations to account A large range of breadboards/protoboards are available from the selector below the component menu. siliconchip.com.au for diode polarity. The text colour for diode type notation/ labelling realistically reflects the typical colours on these diode packages. LEDs are available in five colours and four orientations. Terminal strips are available in a number of different formats including header sockets and header pins and screw type. General terminal strips come in lengths from 2 to 9 terminals/pins per strip. Longer presentations can be provided by placing shorter strips end to end. Under the terminal category are included some specialised items which includes a series of Single-In-Line (SIL) modules with from two to nine terminals, a typical mini stereo socket as used for PICAXE micro-controller programming and the RevEd AXE029 modules intended for plugging onto a breadboard for ease of programming. One can of course still lay out a PICAXE programming circuit on the breadboard using the standard 10k and 22k resistors. Miscellaneous components currently include some 12 device types including LDR, thermistor, clock crystal, resonator, potentiometers and trimpots (both in two orientations), batteries in eight formats from two to four AA cells a 9V battery and a CR3032 3V Lithium cell, 2x16 character LCD modules with serial, i2c and parallel connections, two sizes of keypads, two relay images and several motors: DC, uni-polar and bi-polar steppers plus a servo motor. Switches are provided in four basic packages being SP momentary push button, SPST toggle, SPDT toggle and DIP switch. The pushbutton and toggle switches are provided in four orientations. DIP switches are available as a hexadecimal rotary 6-pin package and from two to nine switches in a single DIP package. the resistor colour code) and with horizontal and vertical orientations aligning with the breadboard holes. Selections now available include: • wire ends to be bare (for insertion into a hole) or insulated for continuation in a new direction; • the body of the wire to be offset vertically and horizontally from the breadboard holes by one-third of a row so two wires can be run between the rows of holes: • wire ends that start and end straight or turned left/up or down/right; • wire end alignment to three positions as left/up from hole lines, on the hole lines, or right/down from hole lines. Note tabs Small one and three-line note tabs are available, akin to post-it note strips, that can have some (short) text on them as indicators or for information. Note tabs are not restricted to alignment with holes and can be placed anywhere on the screen. Memory/screen resolution Wires are an area where extensive permutations have been incorporated. The original scheme started with wires available in ten colours (as black, brown, red, orange etc akin to PEBBLE version 2.4 is a 3.6MB package comprising an HTML program front end and a series of JavaScript files with various functions for the internal applications and utilities which make up PEBBLE and finally a library of component images. The bulk of the memory required is taken up by the component library. PEBBLE runs under a JavaScript-enabled browser. It has been tested by the Author with Internet Explorer 7 and Mozilla Firefox 3.0.11. PEBBLE may function with other web browsers but has not been tested by the author. Note that the browser must allow JavaScripts to operate. (Editor’s note: we can also confirm it runs perfectly on Google Chrome!). Ideally, the screen resolution should be at least 1280 x 1024. The following provides a guide on what can be achieved/seen with various screen resolutions. A minimal PICAXE 08M circuit to allow programming and operation on the breadboard with battery supply. The circuit matches the insert schematic from the PICAXE manual. Adding a pushbutton switch (digital input) and potentiometer (analog input) to the PICAXE circuit in the image at the left. Breadboard wiring siliconchip.com.au September 2009  69 breadboard is fully visible and the breadboard plus the entire off-board component area is also visible without scrolling once the titles at the top of the screen are scrolled out of the way. For longer breadboards, a screen resolution width of 1440 pixels is required for a 44-row breadboard and a width of 1600 pixels is required for a 50-row breadboard without the need to scroll horizontally. Using PEBBLE Just imagine trying to draw out this rats-nest in the conventional way: the likelihood of errors is enormous! However, with PEBBLE, it’s just a matter of moving methodically across the protoboard and reading component positions, then dragging PEBBLE components into the same places on the virtual protoboard. Repeat for all the links and you have a diagram that’s not only easy to follow, it’s repeatable – and it also makes troubleshooting that much easier! At a resolution of 1024 x 768 the screen width is adequate for a standard 23-row breadboard (but not the stretched 23-row Learners Board). The entire breadboard is visible but it will be necessary to scroll down to see the off-board component area and some selectors/buttons at the bottom of the component menu. With a 30-row breadboard, all of the holes are visible but not the right hand border/edge of the board without scrolling horizontally. With a screen resolution of 1280 x 1024, up to a 38-row Expanding the circuit by adding three LEDs as output indicators to the PICAXE circuit. 70  Silicon Chip To start PEBBLE, simply double-click on the PEBBLE. html file within the directory (folder) where you have stored the program package. A desktop shortcut can be created right clicking the PEBBLE html “program” file and selecting create shortcut. Then drag or copy this shortcut onto the desktop for a quick start. Once the program is started, the user is presented with a component menu down the left side of the screen, an empty 23-column breadboard, SAVE/LOAD buttons below the menu together with a breadboard selector. When the breadboard selector is clicked upon, a full list giving all the breadboard permutations is given. Select the desired board type and the displayed board changes instantly without affecting any components already on the board. Components are placed by left clicking the icon on the component menu or dragging to the breadboard. Once on the bread board the component can be further repositioned. Right clicking on a component or wire initiates a component specific pop-up window with various editing options including the ability the copy or delete the component. The pop-up window for many component types has a text input box at the top in which the user can place text for the component label. Remove the default text if no label is desired. The component specific pop-up edit windows allow defining a title/label, selection of package type/size, ori- Click the Save/Load button displays a window with the data for the circuit in the image at the left. Cut and paste to a text editor to save for the future. siliconchip.com.au entation for many discrete components. Once the user becomes proficient in the use of the wire editing window, a wire can be routed to virtually any point on the board in whatever shape or path the user desired. Below the left side component selection menu are two buttons. The right side button labelled “Clear all” does just that. There is the usual “Are you sure?” type pop-up confirmation window in case of an accidental click. Click the “Okay” button in the confirmation window and the breadboard is instantly cleared. The left side button labelled “Save/Load” provides a new window. When clicked the component data for all items including wires on the breadboard is displayed in a list. You can copy and paste this data into a text file, using for example MS Notepad, for saving and future use. To reload a previous design, copy the component data from the saved text file into the window and click to “Load Circuit” button. You are asked to confirm that you wish to delete all existing components, then the new circuit is loaded and immediately displayed. This text file method can also be used to transfer breadboard circuit designs/ layouts with others. To obtain a hard copy of the visual presentation, just press the “Print Scrn” button on your keyboard. Then, using an image editing program such as Photoshop, MS Paint or PaintShop Pro, paste (Ctrl-V) the data into your image editing program of choice. From there you can clip the desired portion and save the image in whatever image format you desire (from those that your paint program provides). So with PEBBLE loaded onto your computer, never again siliconchip.com.au should there be embarrassment over providing an image of what your latest and greatest breadboard project looks like. You will need to ensure that you unzip using the directory structure so that the various file type are placed in the correct sub directories. The package can be placed on any drive or even a memory stick and the main directory name can be changed but the sub directories must remain as defined in the zip file. Accessing PEBBLE PEBBLE V2.4 can be used in either of two ways. Firstly, some sites are hosting PEBBLE in an on-line format so that users can use PEBBLE direct from the internet without having to download a zip file and uncompress the file to store the program on your hard drive. Sites that are providing this form of access to PEBBLE include: www.rev-ed.co.uk/picaxe/pebble www.gadgetgangster.com/toolbox www.picaxe.orconhosting.net.nz/pebble24a Alternatively, some websites will provide the PEBBLE program as a zip file that can be downloaded, uncompressed and stored onto your hard drive, which will enable use of PEBBLE without access to the internet in future. Note that the computer must still have a javascript enabled browser installed to use PEBBLE. www.rev-ed.co.uk/software/pebble.zip www.minisumo.org.uk/pebblev 2_4a.zip SC September 2009  71