Hey guys, need help in trying to optimise/improve my Infra red, transmitter and receiver. Quite new to all this so I’m experimenting. So here’s my progress so far with my circuit diagram. What I’m trying to do is to experiment with the Receiver resistor(Rc(rx)). I put an adjustable resistor instead. Will it minimise the impact of ambient light and will it impact the data rate?

Also, I’m trying to minimise the noise by maybe using an amplifier followed by an RC filter for the different baud rates, maybe 1200,4800 and 9600. But I’m not too sure in how to go about this. Should I maybe do a high pass filter instead?
I have an OP-AMP BI-FET TL082 82-0064 which i can use I guess

 

In the transmitter, you should aim for the base current to be anout one tenth of the collector current, in this case that would be 4mA.

 

In the transmitter, you should aim for the base current to be anout one tenth of the collector current, in this case that would be 4mA.

sorry could you elaborate? ty

 

Your calculations for the base resistor in the transmitter aim to make the base current 100mA.
First you won't get 100mA from RS232 interface.
You need enough base current to ensure that the transistor is fuly conducting (saturated). A useful rule of thumb for that is that the base current should be 1/10 of the collector current. The circuit would probably work with a lower base current than that but it certainly doesn't need more than that.

 

Your calculations for the base resistor in the transmitter aim to make the base current 100mA.
First you won't get 100mA from RS232 interface.
You need enough base current to ensure that the transistor is fuly conducting (saturated). A useful rule of thumb for that is that the base current should be 1/10 of the collector current. The circuit would probably work with a lower base current than that but it certainly doesn't need more than that.

I understand, thanks a lot for the info!

 

You are doing it the hard way.

Modulate the IR transmitter using a 38kHz carrier.
Then use a 38kHz IR receiver module. The range on these things are phenomenal.

 

You are doing it the hard way.

Modulate the IR transmitter using a 38kHz carrier.
Then use a 38kHz IR receiver module. The range on these things are phenomenal.

Yes, those receivers have very good sensitivity and suitable filters built in.

 

You are doing it the hard way.

Modulate the IR transmitter using a 38kHz carrier.
Then use a 38kHz IR receiver module. The range on these things are phenomenal.

only doing it like this is so it helps me understand, and for good practice. Plus have to use what i've got

 

only doing it like this is so it helps me understand, and for good practice. Plus have to use what i've got

Ok then. But still modulate a 38kHz carrier at the IR transmitter and use an LM567 tone decoder at the receiver.
If you have to order an LM567 you may as well order a 38kHz IR receiver.