Intelligent Devices RF Control System with Feedback

[chinngap]

Hi, I am currently doing my final semester project as titled above. :?: My problem is now on the feedback path of the tranmission. I need to think of a way to detect whether the device is in on or off state and then send it to the computer through the transmitter and receiver. How am I going to generate a set of digital data(eg.8bits) to be able to be encoded and sent through the transmitter? If let say I want to detect the voltage level of the device and use the information to generate a digital data, what should i do?Thanks

 

[Nigel Goodwin]

Hi, I am currently doing my final semester project as titled above. :?: My problem is now on the feedback path of the tranmission. I need to think of a way to detect whether the device is in on or off state and then send it to the computer through the transmitter and receiver. How am I going to generate a set of digital data(eg.8bits) to be able to be encoded and sent through the transmitter? If let say I want to detect the voltage level of the device and use the information to generate a digital data, what should i do?Thanks

If it's a voltage level you simply use an analogue to digital converter to give a digital value - if it's a binary (high or low) value you simply use it as one bit in a data word. The feedback path is no different to the original data transmission, treat it just the same.

 

[chinngap]

Hi, I am currently doing my final semester project as titled above. :?: My problem is now on the feedback path of the tranmission. I need to think of a way to detect whether the device is in on or off state and then send it to the computer through the transmitter and receiver. How am I going to generate a set of digital data(eg.8bits) to be able to be encoded and sent through the transmitter? If let say I want to detect the voltage level of the device and use the information to generate a digital data, what should i do?Thanks

If it's a voltage level you simply use an analogue to digital converter to give a digital value - if it's a binary (high or low) value you simply use it as one bit in a data word. The feedback path is no different to the original data transmission, treat it just the same.

Thanks Nigel.Why couldn'y I think of the analogue to digital conveter to do it?Thanks..anyway.

 

[chinngap]

:?: If I have let say 3 devices and for the feedback path of the project, how does the transmitter and receiver can differentiate which feedback refers to which device?Is it better for me to use the 8-bit encoder in this case if I would to maximize the number of devices(for eg.8)? :wink: Thanks!

 

[Nigel Goodwin]

:?: If I have let say 3 devices and for the feedback path of the project, how does the transmitter and receiver can differentiate which feedback refers to which device?Is it better for me to use the 8-bit encoder in this case if I would to maximize the number of devices(for eg.8)? :wink: Thanks!

You simply 'invent' a suitable scheme - one simple way would be to send three bytes of data, as a kind of 'packet' - it's common to send extra data to reliably mark the start and end of the packet. But sending three bytes in quick succession, with a long gap till the next data, works fine as well.

In your case (for feedback) it wouldn't be a problem, the main transmitter sends it's data to the receiver, then waits for the reply - so it already knows exactly when it's expected. So the first byte could be device 1, the second device 2, and so on!.

 

[chinngap]

:?: does anyone know what kind of flash memory and how it is applied without placing it in the computer. Is it we need to create a circuit by ourself? :arrow: This flash memory is to store the address of the devices as the address is changed up to the desire of the user. Thanks. :wink:

 

[Nigel Goodwin]

:?: does anyone know what kind of flash memory and how it is applied without placing it in the computer. Is it we need to create a circuit by ourself? :arrow: This flash memory is to store the address of the devices as the address is changed up to the desire of the user. Thanks. :wink:

It's not very clear what you are asking, but I presume you want to store a device ID in a unit, and be able to alter it from the unit itself?.

This is very easily done with most PIC's, most of them have some internal EEPROM data storage, this is ideal for storing a device ID.

 

[chinngap]

Thanks Nigel !So kind of U! If i choose not to use the PIC, and what i need is a bigger storage, then how does the flash memory can be applied in the project to store tthe address of the devices? This address may changed anytime up to the use's desire.... :wink: Thanks

 

[Nigel Goodwin]

Thanks Nigel !So kind of U! If i choose not to use the PIC, and what i need is a bigger storage, then how does the flash memory can be applied in the project to store tthe address of the devices? This address may changed anytime up to the use's desire.... :wink: Thanks

How much are you likely to need?, you could always interface an external FLASH memory, but it's considerably more work and expense. A simple PIC16F628 has 128 bytes off EEPROM data memory, I suspect that would be much more than enough for storing a device ID?.

 

[chinngap]

Thanks Nigel again . I know PIC can do the job...However, if I wanna to try out the flash memory, is it posibble and do u have any idea? Thanks u very very much! :wink:

 

[Nigel Goodwin]

Thanks Nigel again . I know PIC can do the job...However, if I wanna to try out the flash memory, is it posibble and do u have any idea? Thanks u very very much! :wink:

I don't quite understand what you are asking, do you mean flash memory without a processor?.

 

[chinngap]

Exactly..yes...how to work with the flash memory without the processor. In my case the flash memory is used to store the address (ID) of the devices. Thanks Nigel. Take your time.

 

[Nigel Goodwin]

Exactly..yes...how to work with the flash memory without the processor. In my case the flash memory is used to store the address (ID) of the devices. Thanks Nigel. Take your time.

Presumably it would be possible without a processor?, but I hate to think how many chips it would take. Don't you already have a processor at the receiver end?, if not how are you doing it?.

 

[chinngap]

What do you mean I have a processor at the back of the receiver? Is it posibble for the flash emory chip to function without a processor and we can store the data in and extract it out as well? My receiver will be connected to a device and from the device there, there will be another feedback transmitter which is to feedback the condition of the device. Thanks. Nigel..

 

[Nigel Goodwin]

What do you mean I have a processor at the back of the receiver? Is it posibble for the flash emory chip to function without a processor and we can store the data in and extract it out as well? My receiver will be connected to a device and from the device there, there will be another feedback transmitter which is to feedback the condition of the device. Thanks. Nigel..

What do you actually have at the remote end?.

Usually, these days, it will be a PIC or similar micro-controller, from what you appear to want to do I would have thought that was essential!. A simple (and cheap) PIC16F628 will probably do everything you want at the remote end, and provide the non-volatile storage for device ID.

As I mentioned before, you 'may' be able to build hardware to access a FLASH memory, but it certainly won't be anywhere near a 'one chip' solution. It's certainly not something I would bother attempting.

 

[chinngap]

Yes, I am thinking that actually inside a cpu. there is certain circuit used to extract and store the data from and to the flash memory. And now for my project, I am thinking that maybe i can have the circuit as in the cpu (without a processor) to control the data flowing of flash memory. Do you think this is posibble? And, certainly i know there will not be only one chip. U may view this web :arrow: https://www.pjrc.com/tech/8051/board4/schematic.html
is it related?

 

[Nigel Goodwin]

Yes, I am thinking that actually inside a cpu. there is certain circuit used to extract and store the data from and to the flash memory. And now for my project, I am thinking that maybe i can have the circuit as in the cpu (without a processor) to control the data flowing of flash memory. Do you think this is posibble? And, certainly i know there will not be only one chip. U may view this web :arrow: https://www.pjrc.com/tech/8051/board4/schematic.html
is it related?

That uses a FLASH ROM, is that what you are wanting to use?. If so, you need to arrange address counters, and some way of controlling them to do what you want.

I presumed you meant the FLASH memory cards, which have many less connections.

 

[chinngap]

HI, Nigel, I have a question here, I wish to know what is inside a flash memory when I first bought it? :arrow: What I mean is izzit inside the flash already got data? Thanks Nigel.

 

[Nigel Goodwin]

HI, Nigel, I have a question here, I wish to know what is inside a flash memory when I first bought it? :arrow: What I mean is izzit inside the flash already got data? Thanks Nigel.

I can't say I've ever used one, but I would presume it's blank, with all bits '1'. If it's a FLASH memory card, it could well be ready formatted for use with a computer or camera.

 

[kentken]

What did you come up with? Pic or no Pic?
From what I read so far and the link above, a Pic micro would make it a lot easer.
I cant see why anyone would build such a large circuit, that can basicly do what a pic can do, and easer.

What type of Flash do you want to interface to?
How large are you talking?
What kind of data will be stored?
What is the final project going to do?

I2C interface works great.

Kent