Remote for remote controlled toycar

[Zoas62]

Hello,

Can't actually describe my subject, but i did my best.
Could anyone help me to find schematics of a remote for modelcars.
And maybe some info on how to control servos, I would like to build such a car on my own.

Thanks, Zoas

 

[Elavionic]

If you want some info on servos take a look at www.mp.ttu.ee/risto/rc/electronics/index.htm and
www.public.iastate.edu/~danielj/servotx.html, its a very usefall site. Try to make a search on www.google.com by servo and you'll find a great deal of info. Basic info on servos (almost standard): they work with a modified version of PWM, the frequency is about 50Hz. At the beginning of each period (20 mS) you must aply a pulse between 1mS(for 0 degrees) and 2mS (for 180 degrees), center position is 1,5mS(90 degrees). The frequency doesn't need to be accurate some servos work over 30 to 60 Hz, but the pulses with must be a litle more precise.
The remotes are a bit more complicated. They very from supplier to supplier. Some use PPM modulation (the pulses are sent as as they will be delivered to the servo), other use PCM modulation (the pulses are converted to digital at the trasmitter and then converted to PPM ate the receiver). The modulation can be AM or FM. Most of the remote nowdays use PCM over FM. There are very precise frequencies for remote control, take a look at your country wich can you use. In Portugal, for car, we can use the 27Mhz band with 200kHz spacing.
Siemens had two IC for modeling, with 7 channels over PPM. I don't remember the correct part number, but if you search at their site i believe that you find them. If you want to buid the remote you can use the 433MHz band, but its a open band so you can have some trouble with interference. I buid a robot with a remote and use 8 channel coded in PCM over the 433MHz band, and it works fine.
I hope that this post answer some of your question.

 

[borut]

Hello

Try also on w*w.epanorama.net. There are a lot of links, is a good starting point to search the web for things about electronics, telecomunications, circuits,...

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