What does the project present?
Remote control is a common procedure in many applications. Through audible signals, or mechanical shocks, this vintage DIY electronic kit can operate various electrical or electronic circuits.
How does the assembly work?
The scheme contains two amplification stages and a flip-flop. The amplification is made with transistors T1 and T2, and the bistable circuit is made of transistors T3 and T4; the latter can be switched from one state to another by amplifying the signal at only one input. The applied signal can be audible (clapping, whistling, etc.) or mechanical shocks.
The input signal is applied by means of a telephone headset to the amplification stage, from where by means of capacitors C5 and C6 and diodes D1 and D2 it acts simultaneously on both bases of the bistable circuit transistors (T3, T4). The transistor that was initially blocked goes into saturation, and the other one freezes.
If T4 is blocked, a current is injected at the base of the transistor T5 which saturates it; thus the bulb in its collector lights up.
The characteristics of the power supply and the telephone headset
- Supply voltage: 9V (batteries or DC power sources)
- Telephone headset impedance: 56 Ohm
- Current absorbed from the source: 50 mA max.
List of required components (with recent equivalents):
- T1, T2 - transistors BC 172 or BC 547C
- T3, T4 - transistors (BC170 or BC337)
- T5 - AC181K or 2N2222 / BC546 / BC547 transistor
- D1, D2, D3 - rectifier diodes - 1N4001 or 1N4007
- C1, C3 - capacitors - 10 nF (min. 10V)
- C3, C4 - capacitors - 330 pF (min. 10V)
- C5, C6 - capacitors - 47 nF (min. 10V)
- R1, R4, R13, R14 - 2.2 MOhm resistors (min. 0.25W)
- R2, R7 - 270 KOhm resistors (min. 0.25W)
- R3, R5 - 3.3 KOhm resistors (min. 0.25W)
- R6, R12 - 10 KOhm resistors (min. 0.25W)
- R8, R9 - 150 KOhm resistors (min. 0.25W)
- R10, R11 - 22 KOhm resistors (min. 0.25W)
- R15 - 33 KOhm resistor (min. 0.25W)
- R16 - 33 Ohm resistor (min. 0.5W)
- Telephone headset: impedance 56 Ohm
- printed wiring or breadboard test board
- tin or connecting threads
Download the original IPRS leaflet Baneasa 8107
For a better understanding of the operation of the circuit we will need electronic scheme presented below:
In order to carry out this project in our own laboratory, we will also need printed wiring PCB layout From lower:
sources:
https://roelectronica.blogspot.com/
I saw it and glued it in the version with a microphone. It was a telephone microphone, that shit with a coal bag. Yellow board thing pierced. And that was green on public phones from how much saliva the salt from the speakers.
I remember. We each had phones at home. Now the question is, how can we make a microphone or a 56 Ohm speaker?
You can also use a headset embedded in current landlines, ensuring a bias voltage. It also works with a headset from a current fixed. The headphones were 56, 75 and 300 ohms. The 300 ones were the coolest, with a very strong magnet, they could be heard clearly.
Instead of a headset, there is a microphone with a coil.
When I was a child I made one and used a speaker to which I put a small amplifier with BC 170.
You can mount a speaker with an impedance greater than 8 ohms (sensitivity is low but the effect is similar). There is also a more complicated option; we put another transistor…
I have all kinds of headphones, both newer and older. The Romanian one, from Electromagnetica, with a single coil, 2 magnets and a conical membrane of Al. he had about 56 ohms.
There is also a speaker from Chinese phones, they have 32 ohms or 50 ohms.
Yes, beautiful and interesting comments.
The first time I did the assembly with the parts in the envelope, it didn't work. I did the assembly a second time using Philips BCs and it worked the first time, it still works today, I mounted it with a relay in a Romanian combine.
As Mr. Calciu said, it goes very well with a diff. small chinese recovered from a portable radio or a walkmann headset. If the transistors are good, it is very sensitive on input, do not worry about impedance.
In order to reduce the sensitivity, different values can be probed at R3, which by decreasing it also decreases the sensitivity… practically lays the ground base..of the first transistor in the pre-amplifier.
I changed the input very little, put a 10nF red Russian plate and instead of a helmet, I used a push button, the former mains switch of the combine… from which I removed the mechanical fork, so that it does not remain pressed.
With the microphone he would stop himself from the music ... and so I did it with a push button; Once pressed ON, the second time pressed OFF.
I was in high school at the time - the '90s. The combine exists, and the relay mount in it, I can't wait to get to the country and take pictures.
If used with a relay, do not forget the protection diode 1N4007 placed antiparallel on the coil winding, so as not to burn the transistor that controls the relay.
The diode is placed directly on the winding of the coil in parallel with it, with the anode at minus and the cathode at plus.