I’m new to this and I want to try a simple project to start. The idea is to have an IR sensor transmit a wireless signal to a receiver and set off an LED light when an object gets close to the sensor.
The components I’ve selected are the Hitec Distance Sensor (Product code : RB-Hit-70), the On Shine 433MHz Low Cost Transmitter / Receiver Pair
(Product code : RB-Ons-01), and a 5mm Triple Output RGB LED
(Product code : RB-See-19). Also a power source 9volt battery I guess.
Does this seem appropriate or am I missing something ? Any help would be appreciated.
Great, thanks for the quick responses ! I’m trying to figure out an appropriate resistor for the LED, I see the voltage but where do I find the current ?
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OK I’ve included a diagram here to give a better idea of my dilemma. First off I can’t find a schematic for the IR sensor mentioned above, so I’m not sure how to hook it up, any ideas? Second, once the IR sensor is hooked up I don’t think that’s going to send a signal that will light up an LED, so how do I convert the transmitted signal from the IR sensor into 3v of power for the LED ???
I’ve soldered this circuit together but it’s not working for me. The transmitter and receiver appear to be working, when I move my hand toward the sensor I get a 1.7 v reading on the multimeter from the receiver out pin (pin 2 on the receiver). When I move my hand away the voltage drops to 0v, although it kind of “bounces” down slowly. This 1.7v doesn’t seem to be enough to switch the NPN transistor on, I thought these transistors required very low current to activate them. Any help would be appreciated.
This could work, I would however be careful with the 9VDC battery with the Hiitec sensor (operates at 5VDC) and also the LED (2/3.3VDC).
You can obtain voltage regulators to take your 9VDC source and bring it down to suitable voltages. Mind you a couple of simple resistor dividers may be a good alternatve.
Optionally, a microcontroller can be used on each end to make this more intelligent (and less buggy).
The pinout for the hitec sensor is similar to that of Hitec servo motors. There is a forum post on the Hitec pinout (common question).
In terms of the output on the Receiver, we suggest using a transistor between the output and the LED. The transistor will act as a on/off switch for the LED and also allow a seperate voltage to supply the LED. Not sure at this point if a latching circuit will be required. Other possible tweaks could be the addition of a capacitor between the RX and transistor to stabilise the output.
That is odd, what voltage is applied to the TX pin? To determine what the transistor requires, check out the specification sheet for it. Maybe you can find some that work at lower voltages.
Have you tried removing the current limiting resistor between TX and the transistor? I’d be curious to place a small buffering capacitor in it’s place.
Sometimes it is best to use an encoder/decorder with these modules, but you should be able to get it to work without in theory.
Keep in mind that you will need resistors in order to limit the current in the LED. Also, you may want to add a 5V voltage regulator in order to be able to power the items you selected form a 9V battery.
