Infrared Toggle Switch
Any TV or VCR remote that operates at a frequency of 38 kHz can be programmed to activate this infrared toggle switch. The circuit can be constructed on a veroboard that is quite tiny, an…
Know the mission before touching a wire.
Understand what you are making, prepare the right tools, and make the workbench safe.
Project details
Infrared Toggle Switch is a electronics project. Any TV or VCR remote that operates at a frequency of 38 kHz can be programmed to activate this infrared toggle switch. The circuit can be constructed on a veroboard that is quite tiny, an…
- Source pages
- 215-216
- Named parts
- 3
- Build goal
- Working, tested prototype
Tools you need
- Digital multimeter
- Wire stripper and side cutters
- Soldering iron with a fine tip
- Current-limited bench supply
Use eye protection, good lighting, and a clean insulated surface throughout the build.
Safety precautions
- Disconnect every power source before changing a connection.
- Check component polarity, pinout, and supply voltage twice.
- Use a current limit for the first power-up.
- This project may involve hazardous voltage. Work only with qualified supervision and proper isolation.
Gather, identify, and understand every part.
Use the standardized inventory, then open What's this? to learn each part's role, advantages, limitations, handling, and specifications.
What's this?Image, role, pros, cons, handling & specifications
CD4538
A semiconductor stage performs switching, amplification, regulation, rectification, or logic.
What it does hereIt controls current or signal flow at a defined point in the circuit.
Buy / compare this part ↗Advantages
- Fast and efficient
- Compact
- Can control larger loads from smaller signals
Limitations
- Pin order varies
- Sensitive to overvoltage and reverse polarity
- May need cooling or bias components
Handling
- Verify the datasheet pinout
- Avoid static and soldering heat
- Check notch, stripe, or flat-face orientation
Specifications to verify
- Use the exact model, value, package, and rating listed for CD4538; similar-looking parts are not always interchangeable.
- Confirm pinout, maximum voltage/current, dissipation, gain or forward voltage, and package.
What's this?Image, role, pros, cons, handling & specifications
NEGATIVE
A named project component whose exact role is defined by the source circuit and build guide.
What it does hereIt performs a documented electrical, control, interface, or construction function in this project.
Buy / compare this part ↗Advantages
- Selected for this project
- Can be checked independently
- Supports modular troubleshooting
Limitations
- Substitutes may differ
- Generic names can hide variants
- Pinouts and ratings vary
Handling
- Compare the received part with the source
- Keep it labelled
- Do not force connectors or adjusters
Specifications to verify
- Use the exact model, value, package, and rating listed for NEGATIVE; similar-looking parts are not always interchangeable.
- Confirm dimensions, ratings, connection method, polarity, and environmental limits.
What's this?Image, role, pros, cons, handling & specifications
T1 - transistor stage identified in the circuit
A semiconductor stage performs switching, amplification, regulation, rectification, or logic.
What it does hereIt controls current or signal flow at a defined point in the circuit.
Buy / compare this part ↗Advantages
- Fast and efficient
- Compact
- Can control larger loads from smaller signals
Limitations
- Pin order varies
- Sensitive to overvoltage and reverse polarity
- May need cooling or bias components
Handling
- Verify the datasheet pinout
- Avoid static and soldering heat
- Check notch, stripe, or flat-face orientation
Specifications to verify
- Use the exact model, value, package, and rating listed for T1 - transistor stage identified in the circuit; similar-looking parts are not always interchangeable.
- Confirm pinout, maximum voltage/current, dissipation, gain or forward voltage, and package.
Connect one verified path at a time.
Explore the named components and standardized signal flow, then use Source Check to verify exact physical pins, values, and topology before applying power.
Trace this circuit.
Infrared Toggle Switch: interactive parts, standardized terminals, responsive anchored wires, student explanations, and the original circuit reference in one shared system.
Trace before wiring
Follow power, ground, inputs, processing, and outputs in that order. Never guess a pin from package shape alone.
Connect with power off
Make short, labelled connections and share a common ground only where the schematic requires it.
Inspect every joint
Check continuity, polarity, adjacent shorts, and loose connections before the first power-up.
Open all source diagrams and build views 1 visuals
Confirm the hardware-only control path.
This project does not include firmware in the source. The circuit itself provides the required behaviour.
How to connect
- Match every controller label to the circuit view and source pin map.
- Join grounds before signal wires when separate low-voltage supplies are used.
- Keep motors, relays, pumps, and other loads on a suitable driver and external supply.
Common mistakes
Reversed VCC/GND, board-label versus GPIO-number confusion, missing common ground, and charge-only USB cables.
Troubleshoot
Disconnect loads, continuity-test one path at a time, then test with a current limit.
Software preparation
No IDE, board package, library, or firmware upload is required for this project.
If you add a programmable controller as an extension, document its pin map separately.
How to upload code
The original design is implemented entirely in hardware, so proceed after verifying the circuit and supply.
Assemble, deploy, test, and troubleshoot.
Use the complete source notes in build order, then pass the final checks before calling the project finished.
Build in functional stages
- Power and regulation
- Controller or processing stage
- Inputs and sensors
- Outputs and loads
- Enclosure and strain relief
Power up safely
- Inspect unpowered continuity first
- Apply the lowest safe current limit
- Measure supply rails before signals
- Add one load at a time
- Record expected and actual results
Work from simple to complex
- Confirm power, ground, polarity, and orientation
- Compare each pin with the source
- Test inputs separately from outputs
- Replace only one variable at a time
- Power off before every correction
Follow the documented instructions.
These notes come from this project's source and remain in their original order.
Project overview
Project build noteAny TV or VCR remote that operates at a frequency of 38 kHz can be programmed to activate this infrared toggle switch. The circuit can be constructed on a veroboard that is quite tiny, and it makes use of components that are not hard to find or expensive. For the purpose of signal detection, a TSOP1738 (IRX1) integrated infrared receiver module is being utilized here. This minuscule device's power source is decoupled by the components R1 and C1, respectively (receiver module). The output pin 3 of IRX1 is at a high level while it is in the idle state, which is when there are no infrared signals present. This turns off the monostable that is connected around one portion of the famous dual-precision monostable CD4538 (IC1). In order to prevent retriggering while the active state is being used, its Q output (pin 6) is connected to input pin 4. The length of time that monostable oscillations last is determined by the components R2 and C3 (around one second). Circuit operation When a genuine infrared pulse train is received by module TSOP1738, the output of the module drops low for a brief period of time. As a direct consequence of this, the monostable (IC1) is instantaneously triggered by the negative-going pulse at input pin 5. Now that the flip-flop (IC2) has been set, its Q output (pin 15) will be high since it is being clocked by the output of IC1. Through the use of the transistor T1, this energizes the relay. Freewheeling diode D1 protects the relay from back e.m.f. while resistor R4 controls the amount of current that flows through the base of transistor T1. As previously discussed, when IC2 receives another pulse train from the remote handset, it is once again timed by IC1, and its output toggles in order to de-energize the relay and disconnect the load from the 230V AC mains. Utilize regulated 5V DC power to supply energy to the device. Noise is reduced thanks to capacitor C4, and a buffering function is provided by capacitor C5.
You built Infrared Toggle Switch.
You followed the full workflow from understanding the mission to testing the finished project. That is a real engineering achievement - well done.
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