Version 2
    555 Timer Project | Flashing LED Headband

    The Learning Circuit | element14 presents |  Project Videos



    555 timers are one of the most popular and versatile ICs on the market. In the previous lesson, we learned how 555 timers get used in circuits. There are three main types of circuits in which they are used, monostable, bistable, and astable. Astable circuits are likely the most common use for 555 timers. In this episode, Karen shows how to create an astable circuit using a 555 timer. Follow along as she uses resistors and capacitors to create an RC circuit to affect the timing of the circuit. Karen’s final circuit uses a 4-position DIP switch to allow for the use of 4 different resistors and therefore 4 speeds to control the flashing of LEDs. While Karen uses this circuit to create flashing lights on a headband and a hat, the uses are endless. Try your hand at making the circuit and use it to make art, on decorations, or create warning lights. Come up with other ideas for how to use this circuit and post them in the comments below!


    Final SchematicCircuit Layout

    Supplemental Content:




    Bill of Material:


    Product NameManufacturerQuantityBuy KitBuy Kit
    Electrolytic Capacitor, Miniature, 10 µF, 25 V, 515D Series, ± 20%, Radial Leaded, 5 mmVishay1Buy NowBuy Now
    Ceramic Disc Capacitor, 0.01 µF, 100 V, ± 20%, 5 mmVishay1Buy NowBuy Now
    LM555CN - Timer, Oscillator & Pulse Generator IC, TTL Compatible, Astable, Monostable, 4.5 V to 16 V, DIP-8On Semiconductor1Buy NowBuy Now
    Through Hole Resistor, 220 ohm, 400 mW, ± 1%Vishay1Buy NowBuy Now
    Through Hole Resistor, 1 kohm, 500 mW, ± 1%TT ELECTRONICS / WELWYN1Buy NowBuy Now
    Through Hole Resistor, 22 kohm, 250 mW, ± 1%, Axial Leaded, 200 VTE Connectivity1Buy NowBuy Now
    Through Hole Resistor, 47 kohm, 250 mW, - 1%, 200 V, Axial LeadedTE Connectivity1Buy NowBuy Now
    Through Hole Resistor, 100 kohm, 250 mW, ± 1%, Axial Leaded, 200 VTE Connectivity1Buy NowBuy Now
    Through Hole Resistor, 220 kohm, 250 mW, ± 1%, Axial Leaded, 250 VMulticomp1Buy NowBuy Now
    Prototype Board, 25 x 15 grid, 1.6 mm, 72 mm, 47 mmMulticomp1Buy NowBuy Now
    LED, Cool White, Through Hole, T-1 3/4 (5mm), 20 mA, 3.2 VCreeBuy NowBuy Now
    Slide Switch, SPDT, On-On, 2.54mm, Through Hole, Side, 4 A, 250 VAPEM1Buy NowBuy Now
    DIP / SIP Switch, Raised Rocker, 4 Circuits, Rocker, Through Hole, SPST, 30 VDC, 150 mAGRAYHILL1Buy NowBuy Now
    2226TG -Contact, 2226 Series, Socket, Crimp, 24 AWG, PinMulticomp2Buy NowBuy Now
    2226A-02 -Connector Housing, 2226 Series, Receptacle(Female), 2 Positions, 2.54 mmMulticomp1Buy NowBuy Now
    Wire-To-Board Connector, 2.54 mm, 2 Contacts, Header, Male, 90degAMP - TE CONNECTIVITY1Buy NowBuy Now
    9V battery snap, flexibleMulticomp1Buy NowBuy Now
    Battery, 9 V, PP3, Alkaline, 565 mAhPro Elec1Buy NowBuy Now
    Hook-up Wire Spool Set - 22AWG Solid Core - 10 x 25ftAdafruit1Buy NowBuy Now


    Additional Parts:


    Product Name

    LED strand or chosen Light source