Path: utzoo!utgpu!attcan!uunet!husc6!mailrus!iuvax!silver!commgrp From: commgrp@silver.bacs.indiana.edu Newsgroups: sci.electronics Subject: Re: chase light schematics wanted Message-ID: <7200002@silver> Date: 27 Jul 88 16:11:00 GMT References: <24055@bu-cs.BU.EDU> Organization: Indiana University CSCI, Bloomington Lines: 61 Nf-ID: #R:bu-cs.BU.EDU:-2405500:silver:7200002:000:2410 Nf-From: silver.bacs.indiana.edu!commgrp Jul 27 11:11:00 1988 >I'm looking for the schematics to a simple chase-light circuit, >or anything else that might be neat to hook up to the 9 lamps in >my 9-line ATTfone... > -Dorian-> >|\ /\ \ ARPAnet: dorian@eddie.mit.edu I. Very easy "blinkie" do-nothing machine: Connect blink-LED in series with normal LEDs to make all blink together. Red blinker in series with yellow and green normal LEDs works with a 9v battery; no current-limit resistor needed. Connect several such series-strings in parallel and arrange the LEDs randomly over the surface to be decorated. [designed by Duke McMullan] II. DUAL SEQUENTIAL FLASHER [designed by Chuck Lane] 555 drives two J-K flipflops in 7473 arranged in series as freq. divider (Q output of one connected to C input of other, all J and K inputs to Vcc). Three lines (555 output, Q outputs of both flipflops) go to A,B,C inputs of 74145 10-line decoder; input D is grounded. Power connections: Vcc gnd --------|------------- 555 | 4,8 1 7473 | 4 11 74145 | 16 8 Each of 74145 outputs 0 thru 7 go to two parallel LEDs (select LED pairs for equal brightness in parallel; use clear, undiffused LEDs). Outputs 8 and 9 are unused. All LED anodes are in parallel and connected to +5v thru 47 ohm 1/4w resistor. Adjust 555 frequency as desired; I used 10k from pin 7 to Vcc, 1M between pins 6 and 7, 0.1uf capacitor from pins 6&2 to ground. Arrange LEDs in two sequential strings around a border, such that the two LEDs illuminated at any instant appear to be chasing each other: <-- rotation 4 3 2 1 0 5 7 6 6 7 5 0 1 2 3 4 I used this circuit in an animated name-tag holder for conventions. ICs are on back of a piece of "universal" p-c board, battery holder goes in shirt pocket. Power supply: Four alkaline AA cells in series with 10 ohm 1/4w resistor. When circuit begins to fail from battery depletion, connect shorting jumper across resistor. Battery life is at least 10 hours. -- Frank W9MKV reid@gold.bacs.indiana.edu bitnet: reid@iubacs