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open-hardware-walkie-talkie-diagram DIY Walkie Talkie project - Gadgetronicx

In this post we are going to make simple Walkie talkie circuit project which can send and receive voice over FM frequency band with range Hardware Store Open Until 10 Key of meters. You can make this as a toy or use it for real life applications if you build it durable enough.

This project utilizes FM radio as receiver and FM transmitter to send voice. A person who wants to communicate with the other will have a set of FM radio and FM transmitter and same with the other person. The communication can be half duplex or full duplex and a switch is provided in the circuit to change between these modes. Half-duplex: Bi-directional communication between two people but only one person can transmit and the other can receive at time.

Walkie Talkie is the best example. Full-duplex : In full duplex communication both the parties can send and receive simultaneously. A phone call is best example of full-duplex communication. There is another communication type called simplex.

Simplex is one way communication, radio and TV broadcast example of this. In this Walkie talkie project we Open Hardware Walkie Talkie 20 are providing both half and full duplex feature so that you can use according to your convenience. Full duplex can be used where you need to make conversation with a person for several minutes like a phone call. Walkie Talkie FM Transmitter circuit:. A FM transmitter cannot be simpler than this and very stable at the same time.

The circuit is constructed around only one transistor and few passive components. The microphone is connected to a 10K resistor and ground; this provides proper biasing for the microphone. Between the microphone and 10K resistor the audio signal is taken out via 10uF capacitor. The capacitor allows only AC components of the open hardware walkie talkie diagram voice signal to pass through and blocks DC signal that may enter the base terminal of the transistor.

The two resistors: 15K open hardware walkie talkie diagram 4. You can see a 0. This will bypass or simply pass the high frequency noise that may emerge from microphone to ground, preventing noise being transmitted.

You can spot a 47 ohm connected to emitter terminal, this provides stability to the transistor and prevent excess current passing from collector to emitter while transmitting. Another bypass capacitor is connected across the collector open hardware walkie talkie diagram emitter terminals, this will pass any unwanted high frequency signal generated by LC circuit to ground thus provides a clean open hardware walkie talkie diagram. The variable capacitor and the inductor form the tank circuit which oscillates between 88MHz to MHz.

We will tune this circuit to a fixed frequency between these two ranges by turning the trim capacitor. Note: The trim capacitor is a open hardware walkie talkie diagram terminal device which comes with three terminals to provide mechanical strength; two of terminals are same.

Finally before the antenna there is a capacitor which prevents DC noise signals being transmitted. The antenna can be up to 3 feet to get best range. This circuit can work without antenna from 50 to meter depending on the obstacle between the receiver. We recommend use it with an antenna, an insulated wire with 1 feet long will do the job. The alterations you need to do to the circuit:. In addition to the transmitter circuit you need to make the following changes in the circuit so that you can talk like Walkie talkie in half duplex mode and talk like a phone conversation in full duplex mode.

By sliding the sliding switch ON near the microphone will enable full duplex mode, sliding the switch off will enable half duplex mode. In half duplex mode you need to press the push button to transmit your voice. When you turn off the transmitter to break the communication, the FM receiver will make noise when no radio station transmitter is available, this will annoy the person who is listening to your conversation and also for you.

So it is best to turn on and off the microphone instead of the transmitter. Open hardware walkie talkie diagram Receiver:. You can also use a handheld FM radio as receiver, but there is good chance that you already got a phone open hardware walkie talkie diagram FM radio capability, so you no need to spend some bucks on a FM radio.

How to opearate this Walkie talkie:. You need to make couple of transmitter circuits and you should have couple of FM receivers to communicate between two people.

Now pick a transmitter and switch ON, use a tiny screw driver and turn the trim capacitor left and right slowly until open hardware walkie talkie diagram FM receiver gets complete silent. Now talk on the microphone, your voice should clearly hear on the receiver. Repeat the same step with a different frequency; choose at least 0.

For example: if you selected 96MHz for the first transmitter and receiver setchoose Now give a transmitter and receiver to another guy and try to communicate with 50 meter distance apart in full duplex mode. Gradually move apart further and test the max range. Plug the earphones, put your phone in pocket, place the transmitter at your shoulder and walk like a pro.

If you have any questions regarding this post, comment your open hardware walkie talkie diagram, you can anticipate a guaranteed reply from us. Hi, everyone I finally made this circuit working properly after lot of trials and errors with different Swg coil and Open Hardware Walkie Talkie 40 40pF capacitor.

My nick name is blogthorI am a professional electronics engineer specialized in Embedded System. I am a experienced programmer and electronics hardware developer.

I am the founder of this websiteI am also a hobbyist, DIYer and a constant learner. I love to solve your technical queries via comment section. Thank you for this nice explanation and diagram, is it can work, if I use a variable 30 capacitor in place of the Trim, How many Volt can have the other capacitor and resistor?

I believe you mean variable 30pF capacitor, if so yes! You can use same mentioned values for resistors and capacitors anything above 16V will do. English: Do you plan to make a receiver circuit? Second, Turn ON the transmitter and slowly rotate the capacitor, when both Transmitter and receiver frequency matches, the radio will get completely silenced. At this point you can speak to the MIC, your voice will be received on radio.

Hi, i accidentally bought 20pF trimmer capacito red r. I tried to trim to find the frequency by using my phones built in radio reciver but theres no result?

Is the trimmer the main problem? In addition and i also open hardware walkie talkie diagram thicker coil different from that you guys mentioned as 22 swg coil.

You can still tune the transmitter between 88 to MHz with 20pF caps and with thicker coil. You can try increasing or decreasing the no. Hi, Thanks for the quick response. I will try your suggestions. Sometimes i almost catch the frequency but it gets lost shortly after. I use capacitive electret microfone. Am i using the wrong microphone? If your receiver radio is silent, it means your transmitter and receiver are properly tuned.

I think your MIC is not working properly, you can remove the MIC and apply music signal directly to the transmitter, the music should be heard clearly on radio receiver. If you got a spare MIC try with that. Coil diameter is about 3 to 4mm. Also signal changes as i touch open hardware walkie talkie diagram laptops touchpad.

Breadboard is a very bad choice for prototyping RF projects. They absorb and release tons of RF noise. The reason why the frequency changes when you bring your hand near or away is because of the capacitance of your body which interacts with the transmitter that changes the resonating frequency of the transmitter.

You can make this stable by Soldering your circuit to a general purpose PCB and make is small as possible. The coil is of 4 turns, 22 SWG thickness and 3 to 4 mm in diameter. I found 20Swg wire. What changes open hardware walkie talkie diagram i make in this case? Thanks for the information btw. Please go through the comments, I have mentioned how to tackle with slightly different values of components to one of the readers, there it was about capacitor but the procedure is same for you too.

You cannot use a transmitter as receiver, they both work in very different ways. You need a good FM radio to receive signal. You must understand that there is no circuit open hardware walkie talkie diagram can transmit and receive and no modification will do that. I used a special made plastic non conductive screw driver to tune the capacitor. In here it says use cellphones built-in fm reciever but it sometimes cant catch the right frequency and losts signal.

I suggest you to use a handy old fashinoned fm radio, And recived frequency also drops for every minutes, maybe because of the 9v battery getting drained by time,using a dc-dc reguator might fix it not so sure. Im not an expert. Or you can do your VHF radio transmitter using higher frequencies with different components. A old fashioned radio will always have good sensitivitybut smartphone radio is not bad choice, which we used for testing.

Sensitivity of phone radio may vary model to model. Thanks for your explanations. Try using BF transistor, it is made for radio frequency range it should increase the range further, but we are not sure by how many open hardware walkie talkie diagram it is going to do. Thanks a lot for this great project.

Would you please provide me with a compatable receiver circuit diagram to work with the same Walkie talkie transmitter.

Modern walkie-talkies operate on the FRS/GMRS standards. Both standards use frequency modulation (FM) at or MHz, which is in the UHF (Ultra High Frequency) band. The USRP® device in this example will transmit messages at either or MHz, in a manner that is compatible with FRS/GMRS devices. Jul 19,  · The above Walkie Talkie circuit design can be divided into five different parts. The Audio input, Audio Open Hardware Case Ibm Android output, RF input, RF output and Mixer. For the purpose of easier understanding am going explain the working of above parts of this circuit individually and then put it together as one piece. TRANSMITTER SECTION: AUDIO INPUT. A. Chandra, NIT Durgapur – Walkie Talkie 10 CCA, NITD, 15th Feb, Electromagnetic waves are a form of radiated energy Wavelength (λ) is the distance between a point on one wave and a similar point on the next wave (in meter) Time Period (T) is the time taken by the wave to travel one wavelength distance (in second) Velocity of the wave λ/ T = c (velocity of light, 3x m/s).

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