Digital Proportional Radio Control

[nye]

i want to build a Radio Controlled car my self...i've tried to copy the circuit from my own RC car, whose control is digital proportional, but it is too dificult..i would appeal to anybody to please giv me the web address of a site that has the circuit diagrams for the transmitter and receiver of a digital proportional RC system, or if anybody would mind sharing the circuit diagram they hav with me..i prefer digital proportional since u can control the speed of the car also..i wouldn't mind even if somebody gives me a similar circuit diagram which achieves the same thing as digital proportional..is PWM control similar to it???

 

[audioguru]

Good RC equipment is complicated but is inexpensive to buy. They use custom-made ICs that you cannot buy. It would be expensive and very difficult to make it yourself.

 

[Rolf]

i want to build a Radio Controlled car my self...i've tried to copy the circuit from my own RC car, whose control is digital proportional, but it is too dificult..i would appeal to anybody to please giv me the web address of a site that has the circuit diagrams for the transmitter and receiver of a digital proportional RC system, or if anybody would mind sharing the circuit diagram they hav with me..i prefer digital proportional since u can control the speed of the car also..i wouldn't mind even if somebody gives me a similar circuit diagram which achieves the same thing as digital proportional..is PWM control similar to it???

Don't know much about RC cars except that the toy ones I have seen and used are not proportionally controlled. You should look for information on RC model airplanes, because they are almost all controlled with proportional width PW servos. The PW controllers is simple and can be build from a 555. You could of cause use the transmitter receiver from the toy car and just add the servo and the control circuit. The car would have to be bigger but that is good because then you would have room for a longer antenna and increased control range. There are plenty of information on the net, just do a little Googling.
I have bought Micro Racers for as little as $5.99 and their receiver - transmitters are great for such things as operating your camera remotely. Link: https://www.pbase.com/sinoline/rf_remote_control_for_d7xx

 

[nye]

my knowledge on PW is quite limited..but heard some basic uses of it..yeah..so maybe i'll search and also use some model aircraft circuits for my car..hope it'll work!!!!thanks!!!

 

[giaosucan]

Ive finished my project about RC car . I used H-bridge to control DC motor of the car.My remote control is a RF transmitter operate at the frequency 315MHZ .The distance is over 100 m .It run so good
You can visit this link to detail
**broken link removed**

 

[Nigel Goodwin]

my knowledge on PW is quite limited..but heard some basic uses of it..yeah..so maybe i'll search and also use some model aircraft circuits for my car..hope it'll work!!!!thanks!!!

Don't know what the regulations are in your country?, but in the UK model aircraft use their own specific band - for serious safety reasons. Model cars and boats use a different band to avoid interference - you should NOT use aircraft R/C on a car.

However, proper R/C model cars are freely available, not the cheap toy ones - look for ones by Tamiya and similar. These are proper R/C models, with proper radio control systems - just like an aircraft, but on a band legal for cars.

Have a look at https://tamiya.com/english/e-home.htm for some examples.

 

[nye]

my country is a little bit strict due to security reasons, and i dont think it is legal to fly RC aircraft...so will check with the tamiya website..also will use giaosucan's idea..but must brush up my electronics knowledge!!!specially on H-bridge and those type of stuff...

 

[nye]

does H-bridge enable u to vary the speed of the car??or is it a fixed speed???

 

[Nigel Goodwin]

does H-bridge enable u to vary the speed of the car??or is it a fixed speed???

An H-bridge 'can' allow speed control, but is actually for reversing the motor. Assuming this is for a radio controlled model car?, what you want is an ESC (Electronic Speed Controller), these are freely available along with all the other parts required from radio control and model shops.

 

[Rolf]

my country is a little bit strict due to security reasons, and i dont think it is legal to fly RC aircraft...so will check with the tamiya website..also will use giaosucan's idea..but must brush up my electronics knowledge!!!specially on H-bridge and those type of stuff...

My post about PW servo control of RC models was not to imply that you should use their radio control freq's. Just for you to take a look at their servo systems, they are applicable to all RC remote control. That is the beauty of DIY electronics, everything can be modified to suit your needs. It is much to be learned about PW modulation and servo control on the net, it is really pretty simple, give it another try.

 

[bsnsatyam]

i wants a latest many circuits for home purpose of room current swith baord RF remote controling cuircuits.

 

[BravoKilo]

Radio TX/RX Diagram

To NYE:

If you wish to study or DIY above, google "NORCIM" and "Thoboise" and you will find many RX and a TX circuits there. They are however, FM. it would be wise to start with an AM TX and RX. I HAVE ALL THOSE SCHEMATICS that I have collected over the years. Google "Heathkit" or "RC transmitter diagram" and you will find the Heathkit diagrams which are AM and was popular in the 60's. I haved simpler circuit diagrams though. Now, making the TX and RX is not for the feeble hearted. If you do not have good electronics background, forget it. You listed your address as Sri Lanka and Aus. If you go to Australia, you might find cheap second hands in flea markets or contact modellers and they usually would have old radios, AM type, which are usually in the attic.But if your purpose is to learn,contact me in my email address: rcdevices@yahoo.com.ph. I am in the Philippines.
It would be wisefoprusto DIY a Japanese radio system. I have old Futaba circuit diagrams.

BK

 

[bumpa53]

Citizenship RC help

I have a 27mhz Citizenship Digital Proportional Radio Control for model aicraft. The RC was made in the late 1960's and has been boxed since a catastrophic crash landing in 1970. I recently tried to revive the RC with new batteries but the servos just "chatter" and do not respond to control inputs. I checked the servos and the internals move easily and the motor operates. The pot seems to work. I'm wondering if the crash broke an electrical component or cracked the circuit board. Any suggestions as to troubleshooting would be appreciated. I understand basic theory but am really a mechanical guy. I have a VTVM but no scope. Thanks in advance.

 

[BravoKilo]

analyzing radio systems

Hi Bumpa53. First, makea simple RF detector. u can use ur VTVm but if you can get a small VU meter(any small sensitive meter),put two diodes (1n4148) ,one pointing the arrow to the + terminal,another pointing the anode(-) to the - terminal. Join the two ends(they are of opposite poles). This is your input point. RF signal is AC and the diodes direct the + and the - accordingly. First test is to touch the TX antenna when ON. The meter should kick max. Now,get an earphone or better a smalll audio amp such as those computer external audio amp.Connect the inputs to the meter terminas. you should get a purrring sound. Next, go to your RX, open it and touch the pins on the crystal one at a time with your RF probe. It should move, with one pin stronger than the other. Now, get the audio amp and locate the audio section of your RX which is after the detector diode. You will find this diode connected to the secondary side ofthe black IF transformer. The secondary side has 2 pins, the primary 3 pins. The audio is not on the diode itself but on the other pin of the IF which is connected to the base of a transistor either directly or via a 1k resistor. The audio is on the collector of this transistor. Put an isolation capacitor 10 ufd or so on your audio amp input. ground shud be on the - of the battery. Put your volume control on low as it can boom. Turn on your TX and slowly increase the volume control. You should hear the purring sound. Next, touch the terminal where you plug your servo. depending on the brand, the signal is on one of the outside pin. You should get the same sound but this time, move the gimbal of that channel and you should be able to change the pitch of the sound. If you hear it and the servosdo not work, then the problem are the servos. Borrow a good servo to confirm this. If the problem is in the servos, the only thing you can do as a layman in electronics is to spray contact cleaner on the pot. Never use lubricant like WD40 or any oil base cleaner. Oil is an insulator. You may use Carbon Tetrachloride which you can buy from an airconditioner supplier.

Tell me you name and where you from so I can relate better. Mu email address is rcdevices@yahoo.com.ph. Iam in Manila,Philippines. Of course,if it is something we can share in the forum, we will post it there. Who do you think makes that radio?Japanese? You probably have a Sanwa. The servos are small and the horns are circular like a petal..

BravoKilo

 

[Nigel Goodwin]

If the problem is in the servos, the only thing you can do as a layman in electronics is to spray contact cleaner on the pot. Never use lubricant like WD40 or any oil base cleaner. Oil is an insulator. You may use Carbon Tetrachloride which you can buy from an airconditioner supplier.

WD40 is absolutely brilliant for cleaning pots, it not only cleans, it also replaces the required lubricant - I've been using it professionally for decades now, it's far, far, better than so called 'switch cleaner'.

Don't forget, the pots had lubricant grease in them originally, which was also an insulator - flushing that out without replacing it doesn't do the pot any good.

Didn't think you could buy carbon tet anymore?, and it was always a disaster as an electrical cleaner, as it dissolves far too much stuff

 

[BravoKilo]

WD40 for cleaning pots in the servo

Nigel Goodwin:Thanks for the clarification about using WD40. I never tried it and simply wanted to play safe. We have lots on that here and I will start using it based on your information. I have always used "contact cleaner" and thought that while oil will lubricate, I wasn't certain that it will improve the contact in the pot. Thanks for the information. I really appreciate it cuz it cost much less than a can of contact cleaner here in Manila. As for the carbon tet, it is still sold here locally. Again, I will drop it off my list if WD40 will do.

BravoKilo

 

[audioguru]

WD40 is a perfume. It smells good and evaporates in seconds.
It is too thin to be a lubricant.

 

[Nigel Goodwin]

WD40 is a perfume. It smells good and evaporates in seconds.
It is too thin to be a lubricant.

It doesn't evaporate completely, it leaves an oil residue - which is how it works. Squirt some in your hand!.

But it does smell nice

 

[bumpa53]

Citizenship RC help

Hi Guys,

Thanks for the detailed instructions and comments for troubleshooting my RC.
It was made by a company called "Citizenship" in Indiana, USA. I am in Northeast USA.

I will attempt to check the RC per your instructions. Applying some deductive logic: I don't think the problem is in the transmitter since it worked OK when I boxed it for storage. My guess would be the receiver since it took the crash impact as did the servos. I'd be surprised if all servos failed the same way. I did not mention that I cleaned the wiper on 1 pot with isopropyl alcohol. I did not clean the others.

However, since I know very little and now have some detailed instructions, I will give it a try and update when I know more.

Thanks again.

bumpa53

 

[BravoKilo]

Citizenship RAdio

Hi Bumpa53! ARe you still there? I mean if you are still interested to fix that radio.

Here is my suggestion.

Chances are, that is AM. Find some modellers in yur place and try your TX and servos on another receiver. Problem is if the plugs are different. I suspect the RX. I bet you the company who made that radio is closed. I am sure ai can fix that if I were near you.

BK
Philippines