Beginning Circuitry: Build a Metronome
Spark your interest in electronics and circuitryEssembly Time: 5 hours
Skill Level: Beginner
Are you a practicing musician? Do you love playing your instrument and improving your skill? Well, every musician needs to practice, but how can practice be complete without your very own homemade metronome? This beginner circuit can be a great way to spark your interest in electronics and circuitry. The metronome is powered by a simple 9 Volt battery and utilizes one of the most common timing integrated circuits, the 555 IC. Being both practical and educational, this project is a great way to spend a few hours of the weekend.
Step 1: Examine your perforated board to route components to each other.
Step 2: Solder leads.Begin with your IP socket Pick a spot for it close to the top of the board and solder only a couple of its leads at first. Until you are completely comfortable with its placement, solder the rest of its leads.
Step 3: Adding componentsOften times, it's easier to begin with the lowest sitting components. A lower profile leaves the board easier to navigate around, so we will begin with the lowest lying components: the resistors.
Step 4: CapacitorsCapacitors are next. If you can spare the real estate, bend their leads to a right angle so they can also lie on the board.
Step 5: Wire the boardNow that the components are set go ahead and wire the board. Use solid core wire, since it is easier to work with. Don't forget to use strips as short as you can make them. For the speaker, potentiometer, and LEDs cut some wire about 3-4 inches long and solder the wire to the board. The end of the wire will be soldered to the parts to give more length to them.
Step 6: Attach componentsAttach your potentiometer, speaker, LEDs, battery clip, and switch to the board via extended wires. Although the switch isn't shown on the schematic, it can be easily incorporated into the project. Attach one of the two PINs of the switch to the positive lead (red) of the battery clip. The other pin is connected to the board using wire. The switch should act as an extension to the clip. Insert the timer IC in the correct direction.
Step 7: Prepare enclosureNow it's time for the enclosure. Begin by covering the lid of the box with masking tape, preferably white. With a pencil, ruler and a t-square, carefully mark your holes. I would suggest drawing a grid and using the intersections as points to drill. Center and trace the speaker.
With a pen, mark the spots for the rest of the parts and make sure to leave enough room for the battery. I chose to stand it up at the rear of the box. Make sure your bits are the appropriate size and begin to drill.
After you have drilled the holes for the front of the enclosure, proceed to drill holes in the back to mount your board. Leave room for the battery. Use separate screws, nuts, and washers to mount the board.
The back of your enclosure should look like this, with rubber feet still to come.
Step 8: Make musicYour finished product. Use the nuts and washers that came with the parts to secure your knob and switch to the front of the box. Hot glue works great to attach the speaker and LEDs.
|Description||Manufacturer Part No.|
|Enclosure, high class ABS plastic speedy box||H2851-R|
|Knob, 1/4 shaft, 24mm, black, with set screw||JK-902B|
|Switch, toggle, solder lug, panel mount||1MS9T1B1M1QE|
|LEDs (2), uni-color green, 565nm, 2-pin, T-1 3/4||LG3330|
|Battery, 9V, Super Alkaline||L6F22/VINNIC|
|Capacitor, electrolytic, radial, 22µF, 16V, 20%||R22/16|
|555 IC, Standard Timer, Single, 8-Pin, MDIP Rail||LM555CN|
|IC Socket, 8-Pin, Dual Wipe, Soldertail||6000-8DW-R|
|Resistor (3), 1.0kΩ, 1/2 watt, 5%||CF1/2W102JRC|
|Rubber Feet (4), SJ-5023 Series, Bumpon||SJ5023BLK4|
|Nut (4), Hex, 4-40, Zinc-plated Steel||36012|
|Screw (4), Pan Head, PPN 4-40 x 1/2, Phillips||28655|
|Washer (12), Flat, #4, 9/32 (OD), Zinc-plated Steel||#4FW-R|
|Potentiometer, Resistor, 250kΩ, 10%, 2W, Solder Lug, Panel Mount||--|
|Wire, 22 AWG, Solid, Blue, 100 ft.||9313-LB-R|
|Battery Clip, for 9 Volt||A104-R|
|Speaker, Round, Ferrite, 8Ω, 5W||TR-050F|
|Proto Board, 2.5 x 4.5, 5640 Holes, Plated Thru||PCB-858-R|
Recommended Solder Starter Kit
LEDs will not light, sound isn't produced, turning the knob doesn't affect the tick-rate, etc.
1. Check the soldering job. Make sure the solder from leads don't touch each other.
2. Replace the battery.
3. Match components with the schematic's specifications.
3. Check for damaged components.
4. Make sure polarized components are oriented correctly on the board (e.g. IC, capacitors, and LEDs).
This project was assembled by Ari Dubinsky. Ari is a graduate of Carlmont High School and will be attending Cal Poly San Luis Obispo in the fall of 2010, pursuing a degree in Electrical Engineering. Ari has teamed up with Jameco to accelerate his learning as well as to lend a helping hand to a major electronics distributor. His interests include shredding on the guitar, martial arts, and music production.