serial transmission with radio
- Thread starter husslemk4
- Start date
The PICAXE system should (does) work with 433MHz radio, but of course it's dependent on the type of 433MHz stuff you have.
If you can provide information on the particular 433MHz unit, someone might know about it. Also, what are you using it for? Putting problems in context helps enormously.
Edited by - Fowkc on 04/10/2006 11:16:26
If you can provide information on the particular 433MHz unit, someone might know about it. Also, what are you using it for? Putting problems in context helps enormously.
Edited by - Fowkc on 04/10/2006 11:16:26
I am trying to use the rf solution's AM hybrid transmitter with a HT12E chip to send serial data from a picaxe to drive an LCD. The reciver is the rf solutions AM super regenerative reciver with a HT12D chip. According to the data sheets data can be transmitted at a rate of 40KHz and they operate on a frequency of 433MHz.
I have treid to sent the serial data from the PCAXE by connecting it to one of the data lines of the HT12E, however nothing is being recived at the other end.
I have treid to sent the serial data from the PCAXE by connecting it to one of the data lines of the HT12E, however nothing is being recived at the other end.
DO remember that HT12E (Encoder) and HT12D (Decoder) are there to modulate the carrier based on their own serial code.
They transmit coded data based on the 'parallel' switch pin inputs. You can use DIL switches to set address.
When you trigger an HT12E it will send a minimum of 4 words (if memory severs me) therefore it is NOT switching carrier ON/OFF in 'sympathy' with your Serout.
Similarly, the HT12D requires 2 (or is it 3) identical words to be received before it'll give VT.
Therefore all your timing for Serial is completely up the shoot.
You could, I guess, output PICAXE data parallelly into 4 bit nibbles via HT12E data pins and reconstitute them back to a byte at the other end I suppose. Perhaps using the HT12D 'VT' pin to interrupt.
Try your trasnmission/reception without HT12D/E ics. You may have to play with polarity.
Get hold of Holteks data sheets and try and read them at least 20 times.
I don't know the quality of your radio modules as I use FM and NOT AM. But many PICAXE users have been able to directly use RF modules for transmission/reception without any chips in between.
If you want to improve quality/range get hold of Manchester coding/decoding chips. AND use FM.
They transmit coded data based on the 'parallel' switch pin inputs. You can use DIL switches to set address.
When you trigger an HT12E it will send a minimum of 4 words (if memory severs me) therefore it is NOT switching carrier ON/OFF in 'sympathy' with your Serout.
Similarly, the HT12D requires 2 (or is it 3) identical words to be received before it'll give VT.
Therefore all your timing for Serial is completely up the shoot.
You could, I guess, output PICAXE data parallelly into 4 bit nibbles via HT12E data pins and reconstitute them back to a byte at the other end I suppose. Perhaps using the HT12D 'VT' pin to interrupt.
Try your trasnmission/reception without HT12D/E ics. You may have to play with polarity.
Get hold of Holteks data sheets and try and read them at least 20 times.
I don't know the quality of your radio modules as I use FM and NOT AM. But many PICAXE users have been able to directly use RF modules for transmission/reception without any chips in between.
If you want to improve quality/range get hold of Manchester coding/decoding chips. AND use FM.
It's not exactly clear how you are using the HT12D to drive the LCD or how the system is meant to work as a whole. I don't think that using the encoder and decoder is the best way forward and it would be far better to have the PICAXE directly driving the transmitter and a PICAXE between the receiver and the LCD to do the decoding of received data that end.
As far as I can guess Hussy is doing:
PICAXE+HT12E+RFTx ~~~~~ RFRx+HT12E+LCD
Won't work. Its not really suitable for what (I think) you want to do.
Try:
PICAXE+RFTx ~~~~~~ RFRx+PICAXE+LCD
Obv. you'll have to write code both ends.
No sweat. And potentially many advantages.
Keep it simple. And once you have gained the expertise you'll see how this kind of radio linking can be useful for other projects.
PICAXE+HT12E+RFTx ~~~~~ RFRx+HT12E+LCD
Won't work. Its not really suitable for what (I think) you want to do.
Try:
PICAXE+RFTx ~~~~~~ RFRx+PICAXE+LCD
Obv. you'll have to write code both ends.
No sweat. And potentially many advantages.
Keep it simple. And once you have gained the expertise you'll see how this kind of radio linking can be useful for other projects.