Author: Vasile-ion Diaconescu
Year of publication: 2004
Article taken from the 2004 edition of Tehnium.
What it is?
In TV troubleshooting, various verification and control devices are often needed. The exception is not the operation of checking the remote controls. A simple and efficient installation for this purpose is presented below.
The scheme is based on an infrared radiation sensor produced by Vishay. Next to it are presented the most common capsules for 5V stabilizer, TSOP1738 IR sensor and BC557 transistor.
For the sensor, the far pin is the output pin, Vs (the middle one) is the pin for the supply voltage, and GND is the ground pin. Looking from the front (convex side), the arrangement of the pins is (from right to left): output, power supply and GND.
In order to know if the sensor is receiving something, the output will have to be connected to a display device: a simple LED. As can be seen in the diagram in the next figure, the output TSOP1738 sensor controls a transistor that has an LED in the collector circuit.
For powering the sensor a voltage of 5V will be used, obtained by stabilization with 78L05 steel construction from the 9V voltage. The 4.7uF capacitor performs the filtering of the supply voltage in case of supplying the assembly from a voltage source with transformer and rectifier. Resistance can be 470, 560 or 680R.
How does the circuit work?
The operation is very simple: when receiving an infrared signal, the sensor will convert this information into a pulse train; these, in turn, will operate the transistor, putting it in intermittent conduction; The LED will turn on and off very quickly, like a very fast "signaling". The assembly has a very high sensitivity noticing signals from relatively long distances and even when the remote controls are not pointed at him.
TSOP1738 can be used as the equivalent for TSOP1736. It is recommended that the entire assembly be placed in a box, with the sensor mounted on the outside (with the convex part); the power supply can be made from a 9V battery also fixed in the box; the connection between the battery and the assembly, can be made with a special connector for 9V batteries, houses can be found in trade; a switch for disconnecting the power supply can also be mounted on an outer wall of the box (the diagram with the switch is presented below).
Some tips in case the remote control does not work
- Cleaning contacts from batteries;
- Cleaning the keyboard and wiring with isopropyl alcohol;
- Checking the emitting LED of the remote control, the final transistor, the quartz; the wiring routes will also be carefully inspected.
Careful: receiving signals of approx 38kHz, the mount may not be sensitive to some types of remote controls that emit on other frequencies (115kHz, in the case of remote controls for satellite receivers). The tested assembly received signals from various TV remote controls, CD player and even from TV-Tuner remote controls.
Download the electronic schemes
To carry out this project in your own laboratory, you can download the electronic schemes in .dsn format (TinyCAD design) by here.
In order to better understand the operation of this assembly, we have attached the video materials below where similar circuits are presented:
The presentation picture of this article was taken from https://giphy.com/