433 problems with recieving

[chris.celovic@hotmail.com]

I have 2 18x's and they are set up for RX/TX. The TX is hand held , the RX is fixed at about 50 mts. I send a value to the the rx and it runs some timing serials. I need to send a cancel (reset) comand, so I have made timing loops "e.g. do 1000 until n = n" on the RX. The reason I did this is so I could exit the sub if I pushed cancel on the TX sent a new value and it would not be waiting for a whole timing serial to finish. I've tried the serin line in the loop, and out side the loop but alas, no good. It hangs.

 

[eclectic]

Chris.
Post the code please.

 

[chris.celovic@hotmail.com]

will do.

cheers

 

[manuka]

This may be the old SERIN hangup blues- are you up with this? There are workarounds- do a past Forum search maybe.

 

[chris.celovic@hotmail.com]

2 Options

I am now! What every on is saying is there are 2 options, 1. use a slave axe to check serin (and pass that to the gutsy axe) or 2. check the receiving pin is high (what about rfi)

 

[moxhamj]

The serin hang is probably one of the more frustrating things about picaxes. I'm just completing an RS232 breakout box where the solution is to use 14M chips and implement a 5 wire protocol where lines go high to indicate data needs to be sent. A line status can be checked before entering a serin command. If serin didn't hang then less lines would be needed, but of course, with radio, there is only one line which is the aether. So you either have a picaxe chip waiting for RF signals in a permanent serin state which means it can't do anything else, or you have a picaxe doing things but never able to execute a serin to get data.

The simplest answer probably is option 1. Use an 08 or 08M connected to the Rx to listen all the time, then raise a line high when it has a valid data packet. Use the gutsy picaxe to check that line periodically, and then another line back from the gutsy picaxe to the 08 one to say "send me the data".

 

[Dippy]

Does your RF Rx module have an RSSI output or similar? If so, you can use that. If not use the methods above.

 

[alexthefox]

The serin hang is probably one of the more frustrating things about picaxes. I'm just completing an RS232 breakout box where the solution is to use 14M chips and implement a 5 wire protocol where lines go high to indicate data needs to be sent. A line status can be checked before entering a serin command. If serin didn't hang then less lines would be needed, but of course, with radio, there is only one line which is the aether. So you either have a picaxe chip waiting for RF signals in a permanent serin state which means it can't do anything else, or you have a picaxe doing things but never able to execute a serin to get data.

The simplest answer probably is option 1. Use an 08 or 08M connected to the Rx to listen all the time, then raise a line high when it has a valid data packet. Use the gutsy picaxe to check that line periodically, and then another line back from the gutsy picaxe to the 08 one to say "send me the data".

i was the same problem and did like Dr_Acula wrote.
here http://www.picaxeforum.co.uk/showthread.php?t=8687&page=3 how to connect 2 picaxe (this is for ir, but it work with RF too) and after from master to slave, wire for enable to send data from slave to master if master ready to recive.

 

[chris.celovic@hotmail.com]

Wonderful

Might have to make this a "feature" in a later version (will the new axes still hang?), and locate the RX box behind the firing line. A BIG QUESTION - how do you guys design your PCBs, is there software I can use (freeware of course)...

 

[moxhamj]

Lots of options but I like Eagle because it is free. It has a few quirks eg adding an extra library like the picaxe library seems to only work after clicking the add button about 20 times, but once it is set up and you are past the steep part of the learning curve, it is possible to take a generic idea to a schematic to a board and have the board layout emailed off to China all in one evening.
See http://www.instructables.com/id/Draw-Electronic-Schematics-with-CadSoft-EAGLE/ and http://www.instructables.com/id/Turn-your-EAGLE-schematic-into-a-PCB/ and http://www.instructables.com/id/Professional-PCBs-almost-cheaper-than-making-them-/

 

[Mycroft2152]

Chris,

Check out Diptrace pcb program. I was an Eagle user for three years and changed over to Diptrace a week after trying it out. EAGLE is somewhat difficult to learn and use.

Diptrace has a free version that allows larger pcb boards to be made than the free version of EAGLE.

Myc

 

[chris.celovic@hotmail.com]

PCB

Thank you both very much for posting your opinions.

 

[lbenson]

About 6 weeks ago I did my first ever PCB using http://www.expresspcb.com/ . They have free schematic and PCB layout software which I found to work very intuitively. Unlike with Eagle and some other programs I have dabbled with, most operations worked the way a Windows user expected they would. There is a size limitation on their cheapest boards, but I got two designs on one board, and got three boards for $60US delivered three days after I placed the order and uploaded the files. The PCB layout software does not autoroute.

Mycroft's venture with VSM and Diptrace sounds intriguing, and I may try that next.

The 28X1 & 40X1 chips have hserin commands which allow background serial in to a scratchpad buffer. This solves the "serin hang" problem. No sign that we will get this or a timeout option on the smaller chips.

 

[manuka]

PCBs via China are certainly now an A1 idea, used greatly by us mad Kiwis here in NZ. Even after factoring in p&p, total costs are usually peanuts & delivery rapid, with quality VERY high.NB- minimum orders (10 up- 100 up etc) & initial setup costs may apply.

Hence check the so called "Kiwi Patch Board" which cost us 50p-£1 each (volume dependent) which were designed by Andrew" Brightspark". Although 08M orientated (of course!)-with provision for the normal 3.5mm programming socket,the 7805 based PSU end means they're versatile enough to be used for logic,555 & discrete final circuits- perhaps off 9V (as shown here) or even a 12V SLA.

Thanks to support from our ETITO (E'Tech) trainers,these increasingly are finding use as a NZ schools electronics course standard. Both students & harassed teachers predictably love them, since they're CHEAP,look like a million dollars, are easy to solder & lead on from initial breadboard circuit evaluation. I've had no qualms adopting them for final tertiary projects.

Yes- we're shooting some to Oz. & they'll be showing up in SiChip articles. Stan

 

[moxhamj]

Mycroft - does diptrace have libraries for picaxe chips including the newer ones?

Autorouting can end up being important if the circuits are complex. Simple analog circuits can almost be drawn by hand using the old dalo pen on copper technique, but anything digital tends to get complex very fast and need vias and tracks going between chip pins. I usually go through many iterations of doing an autoroute then undoing it and moving the components closer and redoing it, until the autorouter starts to fail.

Re boards in China, I was chatting via skype to someone in China about boards last night. Minimum order is 3 but most of the cost is setup cost, so 10 boards are only usually $10 more than 3. So it makes sense to design more generic boards that can be used for a number of different purposes and to leave out components as needed.