Easy Radio (PC)

[LeonR]

Im looking at gettting 2 Easy Radio Transceivers at some point soon.

The plan is to connect the picaxe020 board to one, and one module to a PC.
Doing this will allow me to write the AI/Logic on a PC, and use the picaxe to carry out the commands, such as move, return the data from sensors etc.

Im looking at these.


I have looked at the datasheet and see that to connect it to a RS232, you need a circuit/chip involved? I assume its not possible to just connect the RX and TX + PC 5v line to the module directly? Also the signal strength does not have to be connected I assume? And I will need to have a look at the "ready" signals aswell I think (taking up 1 input and output on the picaxe board?).

To connect to a PC, if a circuit/chip is involved, is there a premade circuit avaliable? If not I can build the circuit from the schematic (hopefully LOL)..


Cheers!!!

 

[Dippy]

That module should connect to PIC OK.

Data Sheet says:-
Data Out Low 0.1V and High 3.1V.
Other useful info on Page 15.

It also 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 specifications/performance data).
2. The serial inputs and outputs are intended for connection to a UART or similar low voltage logic device. Do not connect any of the inputs or outputs directly to an RS232 port. The transceiver 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.
3. The ‘Host Ready Input’ should be tied to 0 Volt (Ground) if not used, when handshaking is enabled.
4. The ‘Serial Data In’ should be tied to Vcc if not used. (Receive mode only).
5. Outputs will drive logic operating at 5 Volts and inputs will be correctly driven by logic operating at 5 Volts (CMOS & TTL logic levels)."


So, for safe connection to PC use a MAX232 type device as shown in Figure 11.

You can probably buy premade ones somewhere. But it ain't difficult. The circuit shown in Figure 11 couldn't be simpler.

Its all there....

The RSSI doesn't have to be used but is VERY useful to allow you to sense RF presence and even reject data if the signal is too low. Note the very high impedance load it requires.

 

[LeonR]

Ok thanks! I didn't spot that part of the datasheet

I will try and make that circuit up in that case!

The radio part is going to be the hardest part to get working and a bi learning curve I think!

I think the best way to figure it out is to order them when I need them and play about.

Im assuming the picaxe halts once you use the command to listen for a input from the radio module? (serin?) but I can get round this with an interupt for the input pin? (i did a search and found a post on this).


Thanks!

 

[Dippy]

Best to buy and try. I've never used them, but I DO know that the guys at LPRS are helpful. If you have general queries ask them, they won't bite.
I have spoken to their techy people several times on the phone (yes, I spoke to a human) and found them very helpful and patient (handy for me!).
If you're scared to phone I'm sure they'll be good on email. It'll be quicker/better than posting here for radio queries. Obv don't expect them to be able to provide specifics for PICAXE.

If I were using those modules I would look at using the RSSI signal to make my code jump to a Serin when the signal was over a threshold i.e. ReadADC.. if RSSI > whatever THEN MySerin type thing. You get the idea. I don't know timings of Easy Radio out... thats up to you to play with