Hi everyone. I am new to the arduino. I would like to ask some help regarding my project.
I have just learned that I can use the arduino to send commands to the rc car remote by connecting the arduino to the remote control.
I have read several posts saying that I have to use an NPN transistor.
That I should connect the base to an output pin on the arduino, the emitter to ground, the collector to the switch. and the ground of my remote to the common ground.
the problem is I have tried all those things but it didn't work.
I think i'm doing something wrong.
where should I really connect the pins of the npn transistor?
here is the picture of my rc car remote.
What voltage (how many 1.5V cells) does the remote run on?
The current is likely very low so you should be able to connect your Arduino pins directly to the switch contacts (the little wires on the board, not the big springy parts that I believe are ground).
To activate a switch pionMode(switchPin, OUTPUT);
To release a switch: pinMode(switchPin, INPUT);
Be sure not to activate both FORWARD and BACKWARD at the same time. Also be sure not to activate both LEFT and RIGHT at the same time
the remote requires a 9V supply. i tried using the 5v from the arduino and the switches worked. haha.
so i thought i could just use that. i'm sorry i'm so new to this.
i have programmed one pin as an output so it outputs 5V.
I tried connecting the base of the NPN to that pin on the arduino.
The emitter to the ground of the arduino.
And that same ground to the ground of the remote.
And also the collector to any of the pins of the buttons/switch.
but nothing seems to work.
trish123:
i have programmed one pin as an output so it outputs 5V.
Were you using that pin to power the remote? That would only work if the remote drew less than 40 mA. Try using the +5V pin and Gnd pin for the remote's B+ and B-. If the remote works on 5V you don't need the transistors.
trish123:
should i use an external battery?
For the Remote? Only if it won't run on 5V or the range is so low as to be nearly useless. Then use the 9V battery and the transistors.
When you use NPN transistors be sure to put a resistor (about 220 ohms) between the Arduino pin and the transistor Base. The Base to Emitter junction acts as a diode to ground and will draw too much power from the Arduino pin without the resistor.
thank you so much for your replies. yesterday, I tried hooking up the +5v and ground of the arduino to the +B and -B of the remote.
and then the emitter of the transistor to ground.
the base to a 1k resistor then to the arduino pin.
and the collector under the big springy part of the remote. not the big springy part.
i only tried that for one switch.
the pin was also programmed as as OUTPUT and HIGH.
trish123:
emitter of the transistor to ground.
the base to a 1k resistor then to the arduino pin.
and the collector under the big springy part of the remote. not the big springy part.
what was i doing wrong?
Your description matches mine but your drawn diagram has B and C swapped.
The 1K resistor may be too high a value. If you don't have any other value you can put 2 to 4 of them in parallel to get a lower value (2=500 Ohms, 3 = 333 Ohms, 4=250 Ohms).
I would like to ask some help regarding my project.
