New and few electronics questions

[arieas]

Hi, of course I'm new here and just make a quick intro.
I have been interested in electronics for some time, opened up the computer replaced boards, made a robot, and meddled with small circuits to make all sorts like flashing circuits and steady hand games.

Right, i have a couple of questions for some electronic pieces.

How could I increase the range of control for Remote control device, like a RC car?

What would the best battery type to use for a small device, size of a computer mouse, which could run for around 2 hours or more. The basic power consumption is a small Black and white camera and the motor power.
And the weight is very low, so a heavy battery wouldn't be too good.

[Al_The_Man]

One of the best energy to weight ratio for batteries is Li-Ion.
And I believe you can recharge in any state of discharge when recharging.
Do you want to extend the range of an existing transmitter?
There is a possibility of raising the transmitter voltage a small percentage may help.
Otherwise You could look at the RC groups as they probabally have higher range equipment than that of an the shelf RC car.
Al.

[One of Many]

The transmitter power output would need a boost to get better range. That is also regulated by some form of law similar to our FCC for the particular frequency being transmitted.

The battery life will be dictated by the current draw of your loads. That can be calculated in milliamperhours(mAhrs) or amperhours(Ahrs) once the total current draw is known and how long you expect that to last.

DC

[skmetal7]

to increase the range, wouldnt making the antenna longer help?

[Al_The_Man]

Antenna length is usually tuned to the frequency, full wave - half wave - quarter wave etc.
Al.

[kreutz]

Originally Posted by arieas .................How could I increase the range of control for Remote control device, like a RC car?

Increasing the range of remote control is possible, there are several ways it can be accomplished: the main factor is signal to noise ratio, so in order to improve signal to noise ratio you could use a better RF receiver, a higher gain antenna, a combination of the former two, or increase the transmitter power and/or use a higher gain transmitter antenna. Transmitter power and frequencies are regulated. Higher gain antennas are directional and, depending on the frequency, could be bulky.

You can also change the RF modulation type (depending on what you are using now) and use FM or Digital Spectrum Modulation (the latter at higher frequency, for example: 2.4 GHz)

[NC Cams]

Any time you start to modifly the transmitter of an approved R/C device, you are potentially entering into the realm of FCC involvement. Legally, anytime you have anyone outside of the factory or a factory authorized service center "retune" a radio, you could be in danger of placing transmitted signal outside the federally designated spectrum.

At one time, the FCC looked VERY hard and dilligently at the outlaw use of anything from R/C to C/B radio's. Especially good targets were the unfortunate folks who ran linear amps or other illegal ways to boost signal on the hobby frequencies. The penalties for bogus and/or illegaly modified transmitters were quite draconian.

With the right equipment selected initially, you can transmit radio signals long distances. Keep in mind that hobby R/C signals and frequencies were designed for field of vision transmission ranges - that's what the typical devices are suited for - if you can see it, you can control it - no more, no less.

When you start to push the envelope of range, perhaps you need to upgrade to something other than simply hobby R/C controls (ie FM, short wave, etc). These however, often and rightfully reguire better equipment, training and special licenses.

As good as they are and have gotten, hobby R/C devices are not nor can they probably be readily tweaked into even semi-military range R/C devices.