Materials & Cost

Use 1/4 inch wide tape for wiring in most projects. Peel the paper back from the tape to expose the adhesive side. Major online stores carry this tape. Look for spools of ~22 yards. Usually discounts are available for packs with multiple spools. Look for prices around 10 cents per yard.

These are the lights for your projects. It is easier to locate these in major online stores based on their full name. Use 3mm sizes for projects in this website. Buy these in bulk for about 1-2 cents each.

These projects were completed with CR 2032, CR 2025, or CR 1620 batteries. These batteries may be interchanged as each is ~3V. Battery numbers represent width and thickness. Thus, a CR 2032 is 20 mm wide and 3.2 mm thick. A CR 1620 is 16 mm wide and 2.0 mm thick. Major online retailers sale these in bulk. You should look for a maximum cost of 25 cents per battery.

Transparent tape secures components to your copper or aluminum foil wires. It also acts as an insulator to avoid short circuits. Any inexpensive tape will work. It can also be substituted with masking tape.

Resistance is rated in Ohms. While resistors look similar to each other, their multi-colored lines indicate how much resistance they provide. Some projects on this site require 10K resistors. Major online stores sale these in bulk for about 5-6 cents each.

Photo resistors (also called photo-conductive cells) provide minimal resistance in bright light and large resistance in darkness. Major online stores sale these in bulk for 8-15 cents each. There are several types of photo resistors rated for their light sensitivity. Projects on this site were tested with GL5549, GL5539, GL5537, GL5528, and GL5516 photo resistors. Photo resistors with higher values function best for voltage divider circuits (where darkness lights the LED, however lower values function best for circuits where LEDs light in bright light.

Tilt sensors (also called ball switches or tilt switches) contain tiny metal balls within the component. When the component is jostled, the ball moves and either closes or opens the circuit. Major online stores sale these in bulk for 8-11 cents each (it may help to search for SW520D). Do not purchase mercury based switches for safety and waste disposal reasons.

Paperclips come if different sizes and finishes. You want #1 size (~1.25 inches long) clips with non-skid grooves. Jumbo clips also work but may be difficult to place on some projects. Do not get vinyl coated paperclips because they slide off projects easily. Local stores sale paperclips inexpensively.

Magnetic tape is a great way to temporarily hold some circuit components (e.g., LEDs, paper clips as wires). Thus, it works great for constructing switches and paper-based breadboards to explore more complex circuit constructions. Magnetic tape is easily cut with scissors and includes a paper backing.

The tape shown is 0.5 inches wide and 10 feet long. Look for prices of $4.00 and under in local or online stores.

Binder clips are optional for projects on this site. They can substitute paperclips to secure components and batteries but are more bulky and expensive. Use medium-sized clips to secure batteries.

Because the glue used on sticky notes is easy to remove, it is perfect to temporarily secure components to paper-based breadboards (when they lack magnetic attraction like resistors). Only the sticky portion of the note is needed so any size will do.

You can find these inexpensively at local dollar stores (~$1.00 for 200). They can also be located easily through online retailers.

Paper fasteners (also called brass brads) can be used as rotational switches. Try to purchase 3/4 inch fasteners or larger. Larger fasteners are generally better because they allow more room for fingers to move the switch. Local stores sale these inexpensively.

Aluminum foil conducts electricity and can substitute copper tape. However, it needs to be secured with an insulating tape (e.g., masking, transparent, electrical). If you use aluminum foil, try to avoid creases and wrinkles. Thin strips of about 1/4 inch wide work well. Similar to copper tape, try to use as few pieces as possible to complete your circuit. Generally, you can find aluminum foil inexpensively at local dollar stores.