Hello the inhabitants of our site! He made another homemade product that could be useful for truck drivers. This is an audible warning light that starts to work when reverse gear is engaged, warning about the danger of pedestrians who are at that moment behind the car. It emits intermittent sound signals. The device diagram is shown in the photo.
For assembly, we need the following materials and tools.
Materials: transistors MP39 - MP42 -3 pcs, MP37B or KT312 - 1pc, MP26B-1pc, resistors MLT-0.5w 1kom-2 pcs, 39 kom-2pcs, 510 ohm-1pc, 180 ohm-1pc, variable tuning resistor -10kom- 1pc, diode D 9 V -1pc, instead of it you can use any similar one, for example, D 223, electrolytic capacitors 30 microfarads * 16 v -2 pcs, any relay 12v, you can use a car-1pc, TA-56M telephone capsule or small dynamic head 0.1GD-17, 0.5GD-30-1pcs, Chinese mounting plate 5 * 7cm-1pcs in size, mounting wires for soldering.
Instruments: Soldering accessories - soldering iron, tweezers, solder, wire cutters, pliers, screwdriver, power supply, multimeter. We select as follows.
Step 1. We check all the radio components for operability with a multimeter. On the circuit board, solder the entire circuit of the device, and check the correct assembly.
Step 2 Temporarily disconnect the top according to the scheme the output of the resistor R5 from the power supply "minus 12V", and configure electronic switch on transistors V1-V3. By selecting the capacitance of capacitors C 1 and C 2 we achieve the desired switching frequency of the relay.
Step 3 Now we set up the operation of the sound generator, while turning off the power of the electronic switch. We supply 12V “minus” power to the upper terminal R5, and “plus 12V” - to the lower terminal R6 according to the scheme. Using resistor R6, we set the mode of stable generation. In parallel with the VA 1 dynamic head, a 0.047uF capacitor can be connected to soften the tone.
Step 4. Now having connected everything, according to our scheme, we check the operation of the entire device.
When power is applied to the circuit, the detector emits an intermittent beep. This means that everything is assembled correctly. Now you can put the device in a suitable case and install in car. You can install the alarm next to the reversing lights by supplying plus power from the light bulb, and take minus from the car body. And install a speaker or phone inside the rear bumper, outside the car. That's all, the device is ready
But you need it, or not, you decide.
I wish you all, friends, every success in your work.
Let’s continue to promote our site “bgm.imdmyself.com”, I personally like to work on it! See you again.