Infrared Remote Control Decoder & Switcher Project

Infrared remote controllers are everywhere around us. The majority of home appliances are controlled using infrared remote controls. In this article/video, we learn to build a device that can decode (almost) any IR remote control and use the instructions to switch the relays (loads). So we can use this feature in a variety of applications without buying a new IR remote control and expensive hardware, such as turning ON/OFF the lights, opening/closing the curtains, ... etc. I have used an ATTiny85 microcontroller as the heart of the circuit. The device can record up to three IR codes in the EEPROM memory and switch 3 separate devices. Each relay can handle the currents up to 10A. The load switching mechanism (momentary ON/OFF, toggling, .. etc) can be programmed by the user.

I used Altium Designer 21.4.1 and the SamacSys component libraries (SamacSys Altium Plugin) to design the Schematic and PCB. I also used the Siglent SDS2102X Plus/SDS1104X-E to analyze the IR signals.

The device works stable and reacts well to the transmitted IR signals. So let’s get started and build this puppy!

References

Original Article: **broken link removed**

[1]: Altium Designer electronic design CAD software: https://www.altium.com/altium-designer

[2]: SamacSys Altium plugin: https://www.samacsys.com/altium-designer-library-instructions

[3]: ATTiny85 schematic symbol, PCB footprint, 3D model: https://componentsearchengine.com/part-view/ATTINY85-20SUR/Microchip

[4]: TS2937-5.0 schematic symbol, PCB footprint, 3D model: https://componentsearchengine.com/part-view/TS2937CW-5.0 RP/Taiwan Semiconductor

[5]: L7805 schematic symbol, PCB footprint, 3D model: https://componentsearchengine.com/part-view/L7805CV/STMicroelectronics

[6]: SI2302 schematic symbol, PCB footprint, 3D model: https://componentsearchengine.com/part-view/SI2302DDS-T1-GE3/Vishay

[7]: FDN360P schematic symbol, PCB footprint, 3D model: https://componentsearchengine.com/part-view/FDN360P/ON Semiconductor

[8]: Siglent SDS2102X Plus oscilloscope: https://siglentna.com/products/digital-oscilloscope/sds2000xp-series-digital-phosphor-oscilloscope

[9]: Siglent SDS1104X-E oscilloscope: https://siglentna.com/digital-oscilloscopes/sds1000x-e-series-super-phosphor-oscilloscopes

 

[KlausST]

Hi,

The clearance between relay contact traces and control circuit seems not enough for line voltage.
Did you follow clearance and creepage distance rules?

Klaus

 

[Hesambook]

Hi,

The clearance between relay contact traces and control circuit seems not enough for line voltage.
Did you follow clearance and creepage distance rules?

Klaus

I agree that the creepage can be increased, however, the distance is enough to satisfy the requirement. As a rule of thumb, 1.6kv/mm or 40V/mil should be the minimum creepage (UL796 Standard)

 

[KlausST]

Hi,

I guess you looked at the "functional isolation", but you need to apply "safety isolation".

Just to clarify: If somebody gets hurt or dies because you did not apply the correct value, you are reponsible for that.

Klaus

 

[Hesambook]

Hi,

I guess you looked at the "functional isolation", but you need to apply "safety isolation".

Just to clarify: If somebody gets hurt or dies because you did not apply the correct value, you are reponsible for that.

Klaus

Don't worry, that mostly applies to SMPS designs with high voltage/transient peaks. Also, the distance between mains contacts is huge and more than enough.

 

[Emic89]

You did good work!

 

[Hesambook]

Infrared Signal (a Sony remote)

 

[FvM]

If the control circuit is accessible to the user (e.g. connected to your computer by the programming interface), it must provide double or reinforced insulation to the mains circuit. The required PCB creepage distance for 230 VAC (150 - 300 V phase to neutral) is 3 mm (e.g. according to IEC 1010, similar requirements in other standards), respectively the design won't pass a safety approval.

 

[Hesambook]

If the control circuit is accessible to the user (e.g. connected to your computer by the programming interface), it must provide double or reinforced insulation to the mains circuit. The required PCB creepage distance for 230 VAC (150 - 300 V phase to neutral) is 3 mm (e.g. according to IEC 1010, similar requirements in other standards), respectively the design won't pass a safety approval.

Where is the neutral line here?!!

 

[KlausST]

Hi,

safety regulations don´t care whether you switch phase or neutral ... in any case you have to follow the same clearance and creepage distance values.

The regulations usually take the phase-to-neutral-voltage for determine minimum distance values.

Klaus

 

[Hesambook]

Hi,

safety regulations don´t care whether you switch phase or neutral ... in any case you have to follow the same clearance and creepage distance values.

The regulations usually take the phase-to-neutral-voltage for determine minimum distance values.

Klaus

This is the whole standard. As I said before I followed the UL table. You can follow what you like in your own design.

 

[ZASto]

MAy I ask who stepped on your toes ?

 

[KlausST]

Hi,

I agree that you follow UL table.

This is the whole standard. As I said before I followed the UL table. You can follow what you like in your own design.

Maybe I'm wrong. What I see: The minimum distance on your PCB is somewhere between 1.5 and 2.0 mm
Post#1, blue layer, smallest distance relay center contact copper trace to copper area.
According the regulations and the tables this maybe is sufficient for functional isolation.

But we talk about two isolated nets.
Two isolated nets sometimes are named as primary and secondary.
Here you need to prevent from electric shock, (safety isolation) apply the rules for "reinforced isolation",.
Some rules say you need to double the table values.
Please confirm that you understood the regulations and designed the PCB according reinforced isolation rules.

Klaus

It's not my intention to cause problems, but to prevent you from problems.