How to use 433 as dumb ends

C

chris.celovic@hotmail.com

Member
Hi There

Firstly, I am a plant mechanic. Secondly, I am truly discovering the joys of the 'Axe, very cool indeed, and easy to program. I am designing a TX - RX that will allow me to send either of ten timer commands (e.g high 7 secs low 12 secs - high 7 seconds then reset) to the RX. so far I have managed to program a 18x to take a 10k pot to give me 10 sequences (simple... I know, but extremely satisfying). I now want to output this (wireless) to a unit that will fire up a 12v relay to control some air solenoids. Range is about 50 MTS OMNI DIRECTIONAL so I don't think it can be IR. I ahve read hippy's page (BTW, its very well written) I am looking for help but... If you think I am going about this the wrong way, please give me a better solution.

This is so much fun and much cheaper and safer than my last hobby.

Cheers
 
E

eclectic

Moderator
Chris. A few points.
Firstly, how “Mission critical” or “Safety critical” is this project?

Then, have a look at Stan Swan's repeater arrangement;

http://www.picaxe.orcon.net.nz/all3.jpg

50 metres is possibly marginal for reliable reception, depending on site layout.

Finally, could you provide more information on your proposed layout, hardware
and any potential sources of RFI.

There are a lot of radio experts on this forum, (not me), who can provide help,
when your requirements are more precisely defined.

e.
 
C

chris.celovic@hotmail.com

Member
Thanks eclectic

The circit is for some target turners, 4 to 165 second exposures(low) and 7 seconds(high) at the beginning and end. It is critical that the serial completes. I intend to use it for competition. BTW it is an open area, wth maybe a person betwen the RX and TX.

I wanted to put all of it in a small jiffy box with a selector pot, as I need to pre set the time and then start it (which I have done sucessfully) with a led on the board, now I must look at wireless options.

Hence my idea is that all of the timing is done on the remote. But.. I have considered a 'axe based receiver, which would do the timing, this way the remote would only have to activate it.

RFI is not a problem (ha.. ) but I am yet to test it.

The receiver has a 12v source as it is a larger air solonoid circuit, so I imagine a 12v relay would suffice.

C
 
E

eclectic

Moderator
Sorry, but more questions.

Chris, can I ask some questions concerning the Logic of your system.

Is it for one transmitter. >>> One receiver controlling one target.
Or, one transmitter. >>> Several receivers, each with one target.
Or one transmitter. >>> One receiver controlling several targets.

And then, is it
TX. Enter Delay period. Send “Delay Value” (Dval) (and repeat as required)
RX. Receive Dval. Then wait for “GO” signal.

TX. Send “GO” signal
RX. Start countdown(s). Raise target for 7 seconds. Lower target.

A few other thoughts.
How about an LCD display on the “sender”,
which could indicate the exact value of the Dval to be sent?

Very importantly, how will you KNOW that the receiver has in fact
received the Dval, and is ready to start? Possibly a high power LED?
You're in engineering. Would things ever go wrong? :(

I hope I've made myself clear.

e.
 
C

chris.celovic@hotmail.com

Member
Not a problem, your questions serve to answer a few of mine, especially the nomenclature of it all, thanks.

There is one transmitter. >>> One receiver controlling a group of targets operated by a compressed air circuit activated by a bank of solenoids.

What you have described is exactly what I want, Dval (sent as a string by serout?)

I like the idea of a LCD to confirm he timing (Dval). I have a LCD unit that I would like to connect, but i want to get the TX RX working first)

I don't know how I am going to confirm the RX has the right Dval, I am assuming you are placing the LED on the RX, if so, an audible beep would suffice(what do you think?)

I have set up the Jaycar 433Mhz on a bread board beside the 18x project. I am up to making it work. I am searching for some code that will send something between the two, I have no IC on the sender so I need to check it has received the initiation string (what ever that will be, I am searching for it now).

This is all very new but I am enjoying it, and thank you very much for the reply.
 
E

eclectic

Moderator
Possible starter?

Here's some cutdown code, which I've taken from Stan's link above.
Code: 
'TX
#picaxe 18X

main:
for b1 = 1 to 165
serout 1,600,(85,85,85,85,"ABC",b1)

'serout pin can be changed

pause 1000
next
goto main

'RX
main:
serin 1,n600,("ABC"),b1
sertxd (#b1,"  ")
goto main
There are two SEPARATE programs.
Load then run TX.

Load then run RX, with the programming lead connected.
e
 
Last edited:
E

eclectic

Moderator
Darlington

Chris. First quick answer ; remove the Darlington then
bodge a wire link for the time being.

In a few minutes, I'll send some more info.

e
 
C

chris.celovic@hotmail.com

Member
Thanks e, I was just trolling through the posts and there is one from Technical stating that is the case. I guess after all of the tests i have done it seems the most plausable. :) I bet I will have to bypass the darlington to get the LCD to work too?
 
E

eclectic

Moderator
Please look at CHI030 circuit.

Chris. Look at

http://www.rev-ed.co.uk/docs/chi030.pdf


page 7. You'll see three outlets labelled “Test”

On your actual board, these are near the bottom right.
Check with a multimeter FIRST, then you should be able to use

Output 0 for your transmission.

More in a few minutes.

e.
 
E

eclectic

Moderator
Point 1. Neatest way. Replace the Darlington with one of these

http://www.rapidonline.com/productinfo.aspx?tier1=Electronic+Components&tier2=Resistors+&+Potentiometer&tier3=Resistor+Arrays&tier4=DIL+Resistor+networks&moduleno=65191

Use either a Zero Ohm or say 4.7 Ohm very low resistance.

Or, bodge with eight wire links.

Then ..............
Yet more questions, but, I hope they're relevant.

A. How many solenoids/relays?

B. When you input Target and Delay, are they
i.Sequential: 1 – 12s, 2 - 32s, 3 - 94s etc, OR
ii.Mixed : 1 – 123s, 2 – 9s, 3 – 54s etc?

I've been playing with delay-timers for my cameras.
I can, if you wish, provide some rough code and circuits.
These are based around using a 08M or 18X for transmitter c/w
a 28X1 for the receiver / triggering circuit.

Further thoughts.
The transmitter side can “echo” inputs from button pushes, using LED's.
A better system would involve a serial LCD, for example the AXE033.

On the receiver side, “confirmation” could be via a bank of LED's.
However, using a further 433 Tx/Rx pair might be better to indicate
“safe arrival”.

Final thought, for the moment.
Can you borrow a Scanner Radio that can receive 433 MHz?
They're excellent for field testing and “sniffing” for signals.
Over to you.
 
C

chris.celovic@hotmail.com

Member
Doh, I have been looking at the circuit (page 7) and sometimes you can't see the forest.... To answer your questions, I have built a 10 position selector with 10 x 10k resistors to give me an "indexed pot" thus I can use each of the 10 values to do something.

At present i just "if readadc > 20 then sub" sub being a series of highs lows and pauses.. they don't need to be sequential. However, there is a constant 7 sec HIGH with a low which is the variable face time of the targets nd then a 7 Sec HIGH to finish (at the beginning of the serial the target turn away, then they face for the shooting bit, then they face away again)

If I use 2 chips, I can send select the serial and send something (little) to the Rx which will do all the timing. So the preselecting would be done on the TX unit and when the go button is pushed it would basically start up the second chip. there must be a way to "do nothing" if a clear signal is not sent?
 
E

eclectic

Moderator
I'm assuming it's around midnight on your side, so I'll try and keep this short.

Suggestions;
A. Get the Tx and Rx working FIRST, with simple numbers.
B. Take the two circuits outside and do a simple range test.
C. If you need ten "firing" outputs, plus others, it may be worthwhile thinking about a 28X1.
D. Contact me if you'd like the circuits / program I mentioned in my post above.

e.
 
C

chris.celovic@hotmail.com

Member
e It worked! I have 50mts range with a few obstacles in between. I am sending an uninterrupted stream. Here is the code, note the baud rate, it would only work with this rate, and without the "n".

'TX


main:
for b1 = 1 to 165
'read b1,b0
serout 0,4800,(85,85,85,85,"ABC",b1)
sertxd ("ABC",#b1)
next
goto main

'RX

main:
serin 2,4800,("ABC"),b1
sertxd (#b1," ")
goto main

I am now going to hook up the 2x16 LCD

Thanks again for your time and great advice. c
 
E

eclectic

Moderator
Chris. Thanks for the feedback It's great when projects work!

I'm a little puzzled as to why your setup only works at 4800.
But, if it works, it works.

One suggestion I'd make is to slow down the sending rate.
Put say
pause 50
after each serout from the transmitter.
With your project, a few tenths of a second won't affect the overall outcome.

There's a lot more questions I'd like to ask, but I'll leave you to sort
out the LCD. There're lots of threads on the forum that may provide assistance.
Serial LCD (like AXE033) = dead easy.
Parallel = more difficult and longer to program.
e.
 
C

chris.celovic@hotmail.com

Member
LCD and 433

HI e

I am using Hippy's code for chatter between TX and RX. It seems to be working really well, the cheaper the 433 chips the better range I get. I need a compact antenna for the TX, but I'll do a search.

I need to make a parallel connection to the LCD, but I am designing a new interface circuit to bypoass the darlington chip.

Cheers
 
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