LEDS1• 1
LED Strobe Light
Ramsey Electronics Model No. LEDS1
• Bright blue stroboscope without high voltage or glass tubes.
• Adjustable flash rate.
• Audio mode flashes to your stereo.
• Runs on 12V DC.
• LEDs won’t burn out.
• External trig allows for expandability.
• 3 different LED boards to choose from.
Super-Bright LEDs pulse to your music. Switch over to
stroboscope mode for a super-blue hypnotic flash! Use the
LEDs as a super flashlight. The possibilities are endless!
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PARTIAL LIS T OF AV AILABLE KITS :
RAMSEY TRANSMITTER KITS
• FM10A, FM25B FM Stereo Transmitters
• AM1, AM2 5 Tr ans mit ter
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• FR1 FM Broadcast Receiver
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• TT1 Telephone Recorder
• SP1 Speakerphone
• MD3 Microwave Motion Detector
• PH14 Peak hold Meter
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• WCT20 Cable Wizard Cable Tracer
• LABC1 Lead Acid Battery Charger
• ECG1 Heart Monitor
• DCI1 DTMF Controller Interface
RAMSEY AMATEUR RADIO KITS
• HR Series HF All Mode Recei vers
• QRP Series HF CW Transmitters
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• QRP Power Amplifiers
RAMSEY MINI-KITS
Many other kits are available for hobby, school, scouts and just plain FUN. Ne w
kits are always under development. Write or call for our free Ramse y catalog.
LEDS1 LED Strobe
Ramsey Electronics publication No. LEDS1 Rev. 1.2
April 2003
COPYRIGHT ©2003 by Ramsey Electronics, Inc. 590 Fishers Station Drive, Victor, New York
14564. All rights reserved. No portion of this publication may be copied or duplicated without the
written permission of Ramsey Electronics, Inc. Printed in the United States of America.
LEDS1• 3
LED Strobe Light
Ramsey Publication No. LEDS1
Manual Price Only $5.00
TABLE OF CONTENTS
Introduction ........................................................ 4
LEDS1 Circuit Description ................................. 4
“Learn-As-You-Build” Kit Assembly ....................6
Parts List ............................. ............................... 7
Assembly Steps ..................................................9
Setup and Testing ...........................................12
Troubleshooting Guide .....................................13
Main Board Parts Layout Diagram ...................16
Main Board Schematic Diagram .......................17
LED Board Parts Layout Diagram ....................18
LED Board Schematic Diagram ........................19
Ramsey Kit Warranty ........................................23
KIT ASSEMBLY
AND INSTRUCTION MANUAL FOR
RAMSEY ELECTRONICS, INC.
590 Fishers Station Drive
Victor, New York 14564
Phone (585) 924-4560
Fax (585) 924-4555
www.ramseykits.com
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WARNING: According to the Epilepsy Foundation it is
possible that this kit may present a risk to those with this
affliction. Affected individuals must be aware of the
possible triggering of seizures by certain visual stimuli.
INTRODUCTION
Everyone has seen a strobe light at one time or another. The bright
eye-popping lights are real attention-getters. They typically use Xenon bulbs
which require high-voltage. In recent years, super bright LEDs have become
cheaper and brighter, to the point where they rival flashlight bulbs. Now,
using some of these LEDs, we bring you the LEDS1! The LEDs take the
place of a Xenon flash bulb. You get a nice bright blue flash without high
voltage, and no glass tube to break. Included with your kit is a 9 LED array,
but a 20 LED array is also available from Ramsey. In addition, the LEDs will
last virtually forever instead of burning out after a short time like a tube. As
well as flashing at an adjustable rate like traditional strobe lights, the LEDS1
also has an audio input that allows it to flash to music. Both high and low
pass filters allow the LEDS1 to flash to treble or bass. And for even more
expandability, there is an external trigger jack that allows you to control the
LEDS1 with your own external source or connect two LEDS1’s together.
LEDS1 CIRCUIT DESCRIPTION
Before we begin dissecting the circuit, let’s have a look at the “big
picture” and see what it is that we’re trying to accomplish. What we want is to
have a circuit that will flash a bunch of super bright LEDs at an adjustable
frequency, and also be able to flash them in response to an audio input.
The adjustable frequency is generated by U3, LM555 timer IC. The
potentiometer R19 controls the frequency at which U3 oscillates. The pulses
from U3 are fed to Q1, a power MOSFET. This MOSFET switches all the
LEDs on whatever LED board is plugged in to jack J5. A power MOSFET is
used because it makes a good high-current switch and won’t get hot. That’s
right, the LEDs are drawing enough power that heat is a design concern!
To make the LEDS1 flash to music is a bit more complicated. The
first step is to run the audio through a filter depending on whether you want
the LEDS1 to flash to bass or treble. There are two user selectable filters to
do this: high pass and low pass. The high pass filter will filter out low
frequency signals and allow high frequency signals (treble) to get through.
The low-pass filter attenuates high frequencies and lets low frequencies
(bass) through. The high-pass filter is made up of U1:A and its support
components. The low pass filter is made up of U1:C and its support
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components. The user selects which filter the audio passes through by
pushing switch S1. After being filtered the audio signal arrives at U1:B where
it is amplified slightly by a factor of 22. After this, the amplified audio goes to
U2, an NE555 timer, that is configured as a retriggerable monostable
multivibrator. The circuit produces an output pulse every time the audio signal
gets above its threshold level. For example, consider a piece of music that
has a drum beat. The LEDS1 is set to low-pass the audio. The drum beat
makes it through the filter, is amplified by U1:B, and triggers U2. Now, you
might be thinking: “Isn’t sound a sine wave? Every time the audio reaches a
peak, it would trigger U2 and produce a flashing effect” This is true, and
sometimes a single drum hit will produce a couple of quick flashes instead of
just one flash, because one drum hit contains many peaks as shown in the
picture.
This is where some “tweaking” can come in to play, and is discussed later in
the manual. Now let’s take a look at the parts list and get building!
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RAMSEY Learn-As-You-Build KIT ASSEMBLY
There are numerou s so lde r connections on the LEDS1 printed circuit board.
Therefore, PLEASE take us seriously when we say that good soldering is
essential to the proper operation of your kit.
• Use a 25-watt soldering pencil with a clean, sharp tip.
• Use only rosin-core solder intended for electronics use.
• Use bright lighting, a magnifying lamp or bench-style magnifier may
be helpful.
• Do your work in stages, taking breaks to check your work. Carefully
brush away wire cuttings so they don't lodge between solder
connections.
We have a two-fold "strategy" for the order of the following kit assembly
steps. First, we install parts in physical relationship to each other, so there's
minimal chance of inserting wires into wrong holes. Second, whenever
possible, we install in an order that fits our "Learn-As-You Build" Kit building
philosophy. This entails describing the circuit that you are building instead of
just blindly installing components. We hope that this will not only make
assembly of our kits easier, but help you to understand the circui t you’re
constructing.
For each part, our word "Install" always means these steps:
1. Pick the correct part value to start with.
2. Insert it into the correct PC board location.
3. Orient it correctly, follow the PC board drawing and the written
directions for all parts - especially when there's a right way
and a wrong way to solder it in. (Diode bands, electrolytic
capacitor polarity, transistor shapes, dotted or notched ends
of IC's, and so forth.)
4. Solder all connections unless directed otherwise. Use enough
heat and solder flow for clean, shiny, completed connections.
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LEDS1 MAIN BOARD PARTS LIST
The main board is the larger of the two. Sort and “check off” the components
in the boxes provided. We do our best to pack all our kits correctly but it is
possible that a mistake has occurred and we missed a part. Please note that
physical descriptions of parts are for those currently being shipped. Sometimes the parts in your kit may have a different appearance but still have the
same values.
RESISTORS
3 1K ohm resistor [brown-black-red] (R5,R6,R8)
5 10K ohm resistor [brown-black-orange] (R1,R2,R3,R4,R10)
1 22K ohm resistor [red-red-orange] (R9)
4 68 ohm resistor [blue-gray-black] (R12,R13,R14,R15)
2 100K ohm resistor [brown-black-yellow] (R17,R20)
2 300 ohm resistor [orange-black-brown] (R7,R16)
1 330 ohm resistor [orange-orange-brown] (R18)
1 470K resistor [yellow-violet-yellow] (R11)
1 100K potentiometer (R19)
CAPACITORS
4 .1 uF ceramic disc capacitors [marked 104] (C1,C2,C13,C14)
1 .1 uF electrolytic capacitor (C7)
4 .001 uF ceramic disc capacitor [marked 102] (C3,C4,C5,C6)
1 .47 uF electrolytic capacitor (C9)
2 1 uF electrolytic capacitor (C8,C11)
1 10 uF electrolytic capacitor (C12)
1 33 uF electrolytic capacitor (C10)
SEMICONDUCTORS
Note: Chips may have other numbers and letters on them; the important numbers are those listed in brackets.
2 NE555 timer [marked NE555] (U2,U3)
1 71F7034_H N channel power MOSFET [marked 71F7034_H] (Q1)
2 1N4002 silicon diode (D10,D11)
1 1N270 germanium diode (D12)
1 LM324 quad op-amp [marked LM324N] (U1)
1 7805 voltage regulator [marked 7805] (VR1)
MISCELLANEOUS
2 2.1mm power jack (J2,J5)
2 2.1mm power plugs
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1 24AWG wire, red/black, 7 inches
1 3.5mm stereo jack (J3)
1 RCA jack (J1)
3 pushbutton switches (S1,S2,S3)
1 double sticky foam tape 4 inches
LEDS1 LED BOARD PARTS LIST
The LED board is the smaller of the two.
RESISTORS
4 68 ohm resistor [blue-gray-black] (R31,R32,R33,R34)
1 150 ohm resistor [brown-green-brown] (R35)
SEMICONDUCTORS
9 Vishay Telux™ LEDs (D28,D33,D35,D36,D37,D38,D39,D40,D41)
MISCELLANEOUS
1 2.1mm power jack (J6)
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