Easy Radio anyone?

[AceOfHearts]

Anyone here used Easy Radio wireless serial link?

They can be found here:

**broken link removed**

**broken link removed**

Wondering any one used/use them?

Thanks.

 

[AceOfHearts]

Basically,

I got these from www.active-robots.com, they said what you put in is what you get at the other end, provided baud rate is 19200. The data sheet claims the output can be connected directly to a TTL/CMOS device.

The problem is this. The output from the receiving tranceiver is +/-10V for some reason. This makes it unsuitable to go into my 8051 uC. However, I can get over that using a potential divider.

The bigger problem is this. I checked using the oscilloscope the signal received and compared it with the signal trasmitted. Now, I thought what you put in is what you get at the output. But this wasnt the case. Although the bit stream was identical, the time I was not trasmitting, the logic was 0 (-10V) when it is meant to be a logic 1 according to what I was transmitting.

My computers Terminal/hyperterminal therefore could not make sense of the data, nor could my uC

I had the baud rate of 19200 set on everything.

Any shed of light would be appreciated.

 

[ahmedragia21]

im doing the same project !!!
well , i've got an RF Tx,RX from here in Egypt for 10$
i put a square wave , with 1khz , it was the same on the reciever but there's a propgation delay , i asked the professor he said its not a problem ...

you can contact me @ xgameprogrammer@hotmail.com =)

 

[Nigel Goodwin]

Basically,

I got these from www.active-robots.com, they said what you put in is what you get at the other end, provided baud rate is 19200. The data sheet claims the output can be connected directly to a TTL/CMOS device.

The problem is this. The output from the receiving tranceiver is +/-10V for some reason. This makes it unsuitable to go into my 8051 uC. However, I can get over that using a potential divider.

The bigger problem is this. I checked using the oscilloscope the signal received and compared it with the signal trasmitted. Now, I thought what you put in is what you get at the output. But this wasnt the case. Although the bit stream was identical, the time I was not trasmitting, the logic was 0 (-10V) when it is meant to be a logic 1 according to what I was transmitting.

My computers Terminal/hyperterminal therefore could not make sense of the data, nor could my uC

I had the baud rate of 19200 set on everything.

Any shed of light would be appreciated.

The datasheet says:

1. The module operates internally from an on board 3.3 Volt low drop regulator. The logic levels of the input/output pins are therefore between 0 Volt and 3.3 Volts. (See RS Performance Data).
2. All digital inputs and outputs are intended for connection to low voltage logic devices. Do not connect any of the inputs or outputs directly to an RS232 port. The receiver module may be permanently damaged by the voltages (+/- 12V) present on RS232 signal lines. See Application Circuit (Figure 11) for typical connection to an RS232 port via MAX232 interface IC.

So the output from the receiver should be TTL/CMOS compatible, 0-3.3V or so. I suggest you consult Figure 11 and add a MAX232 if you want to feed directly to your PC.

 

[AceOfHearts]

Thanks

Peace Ahmed,

Nice to meet you. Thanks for your email address.
All the best with your project.

The datasheet says:



So the output from the receiver should be TTL/CMOS compatible, 0-3.3V or so. I suggest you consult Figure 11 and add a MAX232 if you want to feed directly to your PC.

Peace Nigel,

Well, the thing is the output is not 0-3.3V for some very weird reason. It shoots between -10V to +10V as if though it is meant to be for the RS232 port (when it should go through a MAX232). The datasheet says it should be between 0 and 3.3V, but its not so I cannot connect to CMOS/TTL devices.

I am very confused over this, and I did pay a lot of module for these transceiver modules, over £100. It doesnt seem as simple as they made it sound:

"To use these modules, simply connect them to a com port and using either your own software or Hyper terminal set to 19,200 baud, 8 data bits, 1 stop bit, no parity and no handshaking, then, whatever you type in one end will appear exactly the same at the other."

**broken link removed**

Maybe I am not understanding someting, but Im pretty sure I got it all covered.

Anyway, thanks very much for extending a helping hand.

 

[Nigel Goodwin]

Post a picture of how you have it connected, presumably you're doing something wrong somewhere?.

 

[AceOfHearts]

Post a picture of how you have it connected, presumably you're doing something wrong somewhere?.

Ok, I will see what I can do.

Out of interest, have you ever used these devices?

Thanks.

 

[Super_voip]

Haven't used one but I have used packet radio in the past, the Easy radio modules have a 180 characters buffer. If you try to send too much this will cause trouble, but by the sound of it a 3.3V module outputting +\-10V is the real problem. If you have a RS232 port directly connected to the module you may have to start saving for a new one. See figure 11 in the **broken link removed** for the correct way. Are these modules or the evaluation kit?

 

[Nigel Goodwin]

Ok, I will see what I can do.

Out of interest, have you ever used these devices?

No, but I have used plain radio modules, and unless you have a MAX232 they aren't going to output +/-10V.

 

[AceOfHearts]

Hi Nigel, thanks.

Well, there is only threes pin to deal with. That is, Rx, Tx and GND as I am using the Transceiver module:

**broken link removed**

Looking at the bread board, I dont think it is worth taking the camera out, all it would appear to you is a mess of wires due to other devices on my bread board. Thanks for the idea.

I think Active Robots took these modules manufectured by LPRS and added on their own systems, soldered it onto their own PCB, which is why I only have 3 pins and not 9 like the datsheet says. And may be also why I am not getting the eoutput datasheet says.

peace.

 

[Nigel Goodwin]

You need to check the details from Active Robots then, it sounds like you may have a module designed to connect directly to a PC, so it has a TTL/RS232 interface on it.

 

[Super_voip]

If you are using that module then , yes it is RS232. There may/should be a level converter chip on the board, you can take the signal before it is shifted.

 

[Blueteeth]

You have bought modules made by active robots, 'using' the easy-radio modules

I'm sure those boards have a level shifter in them...I've used easy-radio products many many times..but I just bought the modules by themselves (the brass things). Those 'red' boards must have additional circuitry on them to provide +/-10v and it appears they power them with a 9v battery, when the modules themselves can only cope with 6V max - therefore, theres a regulator on board too.

I suggest you either cope with what you have..or desolder the easy-radio modules from that PCB...or buy some new easy radio modules direct from https://www.lprs.co.uk You'll be happy with the results...they really are little wonders!

Blueteeth

 

[AceOfHearts]

Thanks for the responses.

Blueteeth, I tried connecting to the PC directly as well as using max232, nothing.

I emailed active robots with the problem, see what they say tommorrow.

I really am disappointed with my purchase, it cost me over £100
And I only noticed the transceiver modules on its own today. I would have been better off with those and saved fifty quid.

Desoldering is not an option,too messy with little pin left. Active Robots have really done it this time, completely misleading customers with those data sheets. All the handshaking lines have been disabled too and the data sheet is irrelevant.

Can you tell me whether those modules on their own work without an external antenna? What is the range? And can you connect TTL/CMOS on input and on output directly? Do they need anything else to work? Thanks.

 

[ahmedragia21]

ace, do you remember the codes i need =) ?
thanks

 

[AceOfHearts]

ace, do you remember the codes i need =) ?
thanks

I am doing it right now. Thanks for prompting me.

Active Robots Managing Director got back to me (yes in the evening!). He said they are for RS232 ports only. I think it means connects directly to RS232 with no such thing as a max232 (its got it onboard) on either end.

He was kind enough to offer an exchange for the other modules for me.

I think the problem is the way they advertised it. They put the data sheet for the single module for this one, which they modified quite a bit to make it compatible directly with RS232 port. Very misleading indeed.

 

[AceOfHearts]

Ok, I got them to work.

They dont need any RS232 level translator whatsoever, its all built in. BUT the input and output is both RS232.

This means unless I am connecting it direct to my PC, I will have to use a max232 with the uCs. A pity.
The baud rate is set at 19200 and I cant change it. Blueteeth, on the modules you have, were you able to change the baud rates?
Also, Does the internal buffer HAVE TO be full before it transmits all the bytes? Or does it transmit as soon as it received the data?

I have to weigh the pros and cons now. For that, I need blueteeths response to these questions and the ones above . Thanks

 

[Blueteeth]

edit (4 seconds after posting):
LOL didn't see the second page of the topic..oh my..well I hope its still helpful!

Thanks for the responses.

Blueteeth, I tried connecting to the PC directly as well as using max232, nothing.

Are you sure you've got all the rs232 settings right?
Do you know for sure that your comm port on yourPC is working correctly?

The software they provide in a zip file will help. It can at least test the board to see if everything is ok, and that its communicating. But for changing settings...baud, channel, power output, handshaking CRC etc.. etc.. you NEED that software. Otherwise you'll be using the config strings in teh datasheet and typing them in manually in hyperterminal

Even using the modules alone, I got stung by getting several of the individual modules..all with different channel settings...ergo, they would not talk to each other. I had to use the above software to set them all. I also recommend you read the datasheet for the exact module you have (thepart number is on the module ) As the 868/900Mhz ones, only have two channel settings available, 0 and 4.

I really am disappointed with my purchase, it cost me over £100
And I only noticed the transceiver modules on its own today. I would have been better off with those and saved fifty quid.

Maybe so, but..its a learning curve :/ They are still usable of course...maybe not so easy to 'embed' them in a permenant app becauseof the rs232 transciever and the V-reg, but as a development tool, not so bad...saves you havingtoknock up a regulator everytime you want to use them. You could always solder small wires direct to the TX/RX pins, and maybe the handshaking lines toget direct access.

Desoldering is not an option,too messy with little pin left. Active Robots have really done it this time, completely misleading customers with those data sheets. All the handshaking lines have been disabled too and the data sheet is irrelevant.

Handshaking lines been disabled? You can always re-enable them using the software they provide. You can change the baud, channel, RF power output etc.. even the CRC checksum length (8 or 16).

I don't tihnk the datasheet is 'irrelevent' at all. With the module alone the connection to a microcontroller is identical to the connection to a PC, the only difference being the rs232 level shifter in place. The datasheet provided by them is the same from lprs and provides all the info you need. Again, the only difference is the voltage regulator and the max232 on it.

Thats why I'm cautious about third-parties. But, I'm sure LPRS will be willing to help you...I phoned them up, and within 20 seconds the guy onj the end told me he was out of his depth and passed me on to someone else...the designer. Couldn't be happier with the service!

I have desoldered a total of 3 of them from boards I made which were 'destroyed' by customers, and you're right, its messy and a ***** to do, as the pins themselves are held on the module with solder, so they just come off.

Can you tell me whether those modules on their own work without an external antenna? What is the range? And can you connect TTL/CMOS on input and on output directly? Do they need anything else to work? Thanks.

[/QUOTE]

During testing I didn't use an antenna at all, not even a wire, and I got about 10 metres out of it, with full RF power. With antenna's, a good 50 line of sight, and maybe 30 inside a factory (surrounded by EMI and metal). Although I didn't notice much of a difference in range between using a proper SMA 868Mhz antenna, with PCB strip lines, and using just a piece of wire (whip) 8.7cm long :/

I would say yes, you can connect TTL/CMOS, but use protection on the TX from the module, that is, the one coming 'from' the rs232 transciever, as it'll be +/- 7-12V and may fry something. A resistor and a transistor will sort it, or perhaps a voltage divider. I tihnk you can drive most RS232 devices with 0-5V providing the lead isn't too long <4 metres?

And as you may know, TTL UARTS use inverted logic when compared to RS232. The modules themselves use this, but as its going through a max232 (rs232 transciever) that will invert it, so to connect to a microcontroller, you'll needto 'invert it' again. A hassle I know, but a transistor inverter for both TX and RX would do the trick.

It may not be all bad. You could use 'that board' just at the PC end, and maybe buy an individual module to go on a robot, or some custom app. The transcievers rock as far as link reliability goes, as they can 'resend' information that get errors.

Good luck man,

Blueteeth

Yet another edit - christ I've screwed this post up....

In answer to your question

The baud rate is set at 19200 and I cant change it. Blueteeth, on the modules you have, were you able to change the baud rates?

Yes, either use the software they provide (also available from LPRS.co.uk, you must register, but its free) or use the datasheet and type the commands in 'manually' in your favourite terminal program.

Also, Does the internal buffer HAVE TO be full before it transmits all the bytes? Or does it transmit as soon as it received the data?

Depends on two things:
1. The module waits for a 'two baud byte' delay before sending out the contents of its RX buffer...so really...it just waits for a 'gap' in the transmitted data'..so unless it constantly recieves data (unlikely) then it'll send out what its recieved once its finished recieving.

2. You must pull the RTS line low (pin 7 on the module?), otherwise it will just store all recieved data and not spit out a thing. I suspect that either they have it permenantly low on the board, or its connected to the RS232. Either way, it'll send data out as soon as it recieves it, without storing it up in its 80-byte buffer.

 

[AceOfHearts]

Yet another edit - christ I've screwed this post up....

Not at all. Thanks for you extremely helpful post. I apprectiate it a lot.

I am going to send these units off to active-robots tommorrow and get the other modules in. The MD was kind enough to offer me an exchange via email (even though I obviously took it out of its package).

Thanks very much blueteeth for your useful post and to everyone else for their contribution.

 

[raskopi]

i need that codes too pls



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