What's the best way to familiarize yourself with the tens (hundreds?) of thousands of electronic components? One at a time, of course, preferably in the order that interests you.
Your experience from last year has advanced you well along the road and since the vast majority of parts are inexpensive, at the minimal power levels we're working with there's not much to lose by reading and thinking a little before going for it.
Inventory
- Each of the lab's six workstations is equipped with a variable temperature soldering station, Panavise circuit board holder, and variable power supply.
- A Dremel and drill press is available for common use
- An oscilloscope is also available for shared use
- A fixed, gondola-style multi tipout bin cabinet houses a good selection of electronic components
- A 7-drawer movable parts cabinet houses additional tools and support material (screwdrives, nutdrivers, solder suckers, CCB, Acrylic sheets, wallwart PS, etc.)
Concern for our environment is an engineering practice that simply must dominate our project design philosophy. Even though our circuits require only small scale DC power levels, consideration of the various power options available to us is a very important design decision.
AC-DC Variable Power Supply
Each of your workstations comes equipped with an AC-DC Variable PS. This is a good choice for prototyping and debugging activities. Banana- and alligator-type plugs are available.
AC Adapter
For stationary indoor applications close to a wall receptacle an AC adapter (aka wall wart) is a good choice. These devices transform household AC into an approriate DC source. When selecting an adapter pay close attention to voltage, current, tip and polarity specifications. These devices should be unplugged when not in use to eliminate power consumption completely.
Rechargeable Batteries
Since the disposal of non-rechargeable batteries is of environmental concern, portable projects that require small scale power supplies should be designed with a rechargeable power source in mind. To support this strategy, each of you has been provided with a selection of AAA, AA, and 9V rechargeable batteries.
Solar Cells
For outdoor applications, solar cells are the natural choice for many projects. Cells come in a wide variety of styles and ratings but price remains a consideration. There are an ever-increasing number of solar-powered products coming to market and thought should be given to saving the cells of those devices that have reached their end-of-life. The cells can be used to power your projects directly or used to charge batteries from which the power is drawn. In some cases, well-matched cells, batteries and loads can eliminate the need for a charge controller unit that prevents the overcharging of batteries leading to reduced performance.
As a developer you have a number of options when it comes to the surface on which to mount your components. A few of the options aviable to us are summarized below.
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Point-to-Point Copper Board
A predrilled fiberglass board laminated with copper-encircled holes is probably the simplest mount for the components of your circuit. Particular attention must be paid to the pitch (distance between holes) of the board as it must be compatible with your components, particularly your chip seats (IC mounts). The ease with which the components are dry fit on the board is offset by the tricky, unforgiving technique of soldering wires within relatively small tolerances. Nevertheless for simple circuits, this is a good option.
StripBoard (Veroboard)
For larger circuits, stripboard is a good option. It is similar to your solderless breadboard in that there are long rails of electrically continuous holes that , if desired, can be interrupted by using an X-ACTO knife to make a slice across the rail.
Copper Clad Board
Copper clad Board (CCB) is a laminate of a fiberglass core and either one or two thin side of copper. The trace of your circuit can be hand-drawn with a Sharpie marker (below left) and then placed into a tank of etchant (we use Ferric Chloride). After 10 minutes or so, the etchant removes any exposed copper, leaving behing the copper protected by the marker. Paper towel with nail polish remover can remove the Sharpie ink.
EAGLE
The ability to manufacture a printed circuit board to specification yourself is an impressive skill. This course will introduce you to this technique and, with practice, you can become quite proficient. The light version of EAGLE can be used to layout your circuit prior to laser printing it onto blue toner transfer paper. The heat from a clothes iron is used to transfer the toner (plastic) to a prepared copper clad board, prior to etching (below right).
Two examples from former ACES (I. Comery and J. Gettings) appear below. Here's the first documented attempt by former ACES a few years back!
The Work Backwards strategy is seldom more important than in electronics applications. Before starting, wise students envision such details as appearance, ergonomics, durability, scalabilty, and maintainability of their final product. Fortunately there are a wide variety of choices for the mounting of your projects.
Acrylic Sheets
Probably the most versatile option. Inexpensive sheets of various dimensions can be readily purchased from hobby, hardware, and home improvement outlets. They can be further cut to any desired size, drilled, molded with the use of a heat gun, welded, and sandwiched in parallel with your CB with the help of threaded standoffs. The transparent property of this material typically enhances the esthetics of your final result as the components are readily visible.
Project Boxes
A wide variety of project boxes are available, many designed specifically for the housing of electronic circuit boards. These are also available at many hobby, hardware and home improvement outlets.
Product Tins
With a little imagination, gum, mint, and candy tins offer both functional and whimsical enclsoure strategies for your projects.
Formal Enclosures
For the more serious, custom developer, a wide variety of enclosures are available for specific applications. Check out the product line of Hammond, one Canadian manufacturer based in Guelph, Ontario.
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