Problem Encounter in RS485 Circuit

I had designed a little board to interface USART to RS485 circuit that has two types of connection: one row of the DIP MAX232, or the ISP header for ATmega64-128-1281-2561 family. 

But after few hours of design, I had decided to improve the circuit, by adding automatic capabilities to the T/R signal, instead of using SCK from the ISP header.

After 2 hours of using Google doing some search for circuits that automatically switch T/R signal, I didn't find anything interesting about the problem I have. Only one circuit that uses a simple transistor and few resistors, but that doesn't satisfy me, since I'm not sure if I do switches off the transceiver too early after the last bit had been sent.

I must say that I have a little being lazy guy, since I'm asking for suggestions about that which I think it’s a good idea to ask some help from you guys because I know some of you may encounter same problem as I encounter right now.

My first bet would be to add a capacitor between T/R pins and ground or VCC to add some delay.

Has someone experience with this kind of circuits? Can you share your idea and thoughts about it or someone that can give advice about this?

Bass-Treble Circuit Using Op-Amp 741

Will make this bassamplifier circuit quick and easy. I’m creating a bass-treble circuit using the Op-Amp741. Yes it is simple but don’t under estimate because it is also a powerful bass, treble, volume control is made by General Op-Amp IC LM741.  The maximum voltage that you can input in this powerful bass is 12V, but don’t worry because this circuit also works in 9v and 6 Volts. The circuit has inbuilt pre-amplifier also.

Parts:

IC LM741 x1
T/C 10k,22k,100k   All x1
Triansistor BC148/548   x1
220uF/25V   x2                 
4.7uF/25V  x2
2.2uF/10V x1
10uF/25V x1
Small resistances x12p
Small PF    x5p

Automotive QVGA Time of Flight Sensor

I was searching about the MLX75 automotive sensor that suits to my project, which I planned to make and as well suitable for LED or lase illumination. I planned to use this MLX75 because it has up to 40 MHz sensor modulations and high ambient light robustness.

So after doing long day research about the project that I planned to make, I finally found this site which I think it can help me a lot when it comes to MLX75 because they explain it well and the function of it. I also understand that aside on automotive QVGA Time of Flight sensor of MLX75 it has also response range 800-900 nm.  You can check the details about automotive QVGA Time of Flight sensor, for you to read and understand the function of it as well as the additional features of the MLX75023 sensor.

MLX71120 and MLX71121

Few days ago I was created a circuit diagram using the 315MHz ASK transmitter IC (integrated circuit). This time I would like to study or doing some research about the RF receiver with a use of MLX71120 and MLX71121 RF receiver applications in a balanced loop antenna.

The good news is, after doing plenty of research about RF receiver using MLX71120 and MLX71121 I found this site of Melexis that explain well on the function and where to use this RF receiver. Upon reading and exploring the site I found out that using this MLX71120 and MLX71121 will need exact computation.

Check this RF receiver MLX71120and MLX71121 for your reference.