Beginner

Ok I am a total novice, so have no experience but wanted to try something new. Purchased a 20M controller on a DIY project board kit decided to make a series of flashing LEDs fed through the Darlington driver.

Downloaded the flowchart software and installed the USB serial cable generated a small program and down loaded to the chip which indicated had completed successfully.

Disconnected and plugged back into the battery but nothing.

Reconnected the serial and ran the chip using the simulator and got my flashing lights so all good when connected to the computer.

Downloaded program again and still the same issue.

I am using 3 x AA batteries, (new) and running the Darlington through the same power but nothing works unless it's plugged into the PC.

Any ideas what I am doing wrong?

Steve
 

eclectic

Moderator
Ok I am a total novice, so have no experience but wanted to try something new. Purchased a 20M controller on a DIY project board kit decided to make a series of flashing LEDs fed through the Darlington driver.

Downloaded the flowchart software and installed the USB serial cable generated a small program and down loaded to the chip which indicated had completed successfully.

Disconnected and plugged back into the battery but nothing.

Reconnected the serial and ran the chip using the simulator and got my flashing lights so all good when connected to the computer.

Downloaded program again and still the same issue.

I am using 3 x AA batteries, (new) and running the Darlington through the same power but nothing works unless it's plugged into the PC.

Any ideas what I am doing wrong?

Steve
Welcome to the Forum.

Can you give us some more details about the

DIY Project board kit?

e
 
The kit was a self assembly AXE 005U

Supplied with 20M chip and Darlington, board, resisters capacitor, and serial socet and USB cable

Steve
 

AllyCat

Senior Member
Hi Steve,
... ran the chip using the simulator and got my flashing lights so all good when connected to the computer.
The "simulator" has nothing to do with the external hardware, but are you are saying that your hardware (i.e. the LEDs on the prototype board) are all working correctly when the programming cable is plugged in, but the prototype board will not restart when the programming cable is unplugged? That is nearly always caused by the 10k pulldown resistor on the serial input being missing or faulty (including a bad connection).

Cheers, Alan.
 

tmfkam

Senior Member
There is a possibility that your battery pack is not providing enough voltage (oomph!) to the LEDs. The LEDs will need at least 2V across them and the darlington may "drop" almost as much, leaving little left to actually light the LEDs. It could be that your circuit and program are working, if very faintly. I would try removing the darlington driver, place a couple of 100R resistors horizontally across two of any of the inner darlington pins (not the top or bottom pairs) and see if any of the LEDs light up then. That should eliminate my theory of low drive to the LEDs. Connected this way the LEDs might be off when you expect them to be on, and on when you expect them to be off. Hopefully "something" will happen. If not, further diagnosis might be needed.
 
Hi Steve,

The "simulator" has nothing to do with the external hardware, but are you are saying that your hardware (i.e. the LEDs on the prototype board) are all working correctly when the programming cable is plugged in, but the prototype board will not restart when the programming cable is unplugged? That is nearly always caused by the 10k pulldown resistor on the serial input being missing or faulty (including a bad connection).

Cheers, Alan.
Hi AllyCat

On your suggestion I did remove the 10k resister and tested it but it measured 9.7k so put back and resolderred but the issue remained.

Any others ideas welcomed

Thanks for your response.
 
There is a possibility that your battery pack is not providing enough voltage (oomph!) to the LEDs. The LEDs will need at least 2V across them and the darlington may "drop" almost as much, leaving little left to actually light the LEDs. It could be that your circuit and program are working, if very faintly. I would try removing the darlington driver, place a couple of 100R resistors horizontally across two of any of the inner darlington pins (not the top or bottom pairs) and see if any of the LEDs light up then. That should eliminate my theory of low drive to the LEDs. Connected this way the LEDs might be off when you expect them to be on, and on when you expect them to be off. Hopefully "something" will happen. If not, further diagnosis might be needed.
Hi tmfkam

Still no luck I am afraid. I assume this means that I am not getting as far as the Darlington other than when plugged into the serial cable so is the issue with the picaxe chip not going high or low other than when the serial cable is plugged in?.

I have now added a single LED on terminal four of the Darlington as this seems to be the initial stumbling block to resolve so now I have just one LED that comes on and off but only with the serial plugged in. Disconnect the serial cable and it stops

I am totally perplexed after following the instructions, checked all my solder joints as to why this would not work.

Just in case it effects it I have placed the second 1k resister in the RPU slot to pull pin C.0 high

Steve
 

AllyCat

Senior Member
Hi,

As you have a multimeter, you can make the direct measurement that the voltage on the serial/programming input (Leg2) is always low, whether the cable is present or not. That leg must always be low (<1v), or the PICaxe waits for a new program download. Obviously it's also worth checking that the supply rail is as expected, etc.. There are also tests within the Program Editor which should return the type and version number of the PICaxe (you said 20M, but it's presumably 20M2 ?), which then restarts the program afterwards.

It's difficult to visualise what else might be wrong, so perhaps it's best to post your full program code, preferably within [ code] [/code] tags.

Cheers, Alan.
 

eclectic

Moderator
@Stevefaull

As well as the program, could you provide details of exactly

what is connected and importantly, how?

Perfection would be a full schematic
and a couple of high quality photographs.

e
 
Guys

I can get schematic but it is as the PDFs given with the starter pack with options that I have placed the 1k resister to pull C.0 high and I have placed the link so that I can provide output power from the Darlington on the same supply. This may need to be changed as I am intending to run up To 4 LEDs of each of the Darlington outputs but that may be the next problem to get over.

I have added front and rear photos in case it is something obvious that my limited experience has not seen.

Regards
 

AllyCat

Senior Member
Hi,

Yes, there are file size (and file type) limits, but I'm not sure where they're listed. So you may need to reduce the file size from a modern camera/phone. Around a 100kbyte, .JPG should be "safe" and give enough detail.

As it's a kit, we have to make a reasonable assumption that the components are all correct (in particular that a supply decoupling capacitor is fitted!) but an assembly error is obviously possible (and hard to find or predict). Also, most of us don't know what is actually supplied in the majority of the kits. My other concern is that perhaps you don't fully understand the limitations of the "Darlington" output device, for example that it can only "Sink" (i.e. pull down) current from the LEDs, which must receive current from another source.

Cheers, Alan.
 
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Hi,

Yes, there are file size (and file type) limits, but I'm not sure where they're listed. So you may need to reduce the file size from a modern camera/phone. Around a 100kbyte, .JPG should be "safe" and give enough detail.

As it's a kit, we have to make a reasonable assumption that the components are all correct (in particular that a supply decoupling capacitor is fitted!) but an assembly error is obviously possible (and hard to find or predict). Also, most of us don't know what is actually supplied in the majority of the kits. My other concern is that perhaps you don't fully understand the limitations of the "Darlington" output device, for example that it can only "Sink" (i.e. pull down) current from the LEDs, which must receive current from another source.

Cheers, Alan

Hi AllyCat

I have now attached a photo of the board that I created from the starter kit. Just to offer an overall concept of the project, I am hoping to create five separate strings of LED lights. Each string will have 4 red LED that I want to make blink in a way that makes them appear as random. I have been able to create the program with each string having a different high and low period so that they appear as random but it is the physics of actually making them work from the board. The program to s straight forward and is basically switch pin high, pause, low, pause, repeat.

At this time I am only working with a single LED on pin 4 but this is only blinking when the serial cable is plugged in. I had linked the power feeding the picaxe to the Darlington to share but assume that using 4.5v may not be suitable so will need the drive the LEDs separately so assume this link will need to be removed and a separate supply added. Ultimately I also want to include a trigger that activates all the lights to come on for a short period of time and them revert back to the slow blinking.

The problem I have is that I am a Novice so despite trawling through article after article I don't really know what to look up, so end up reading through loads of information just to see if it gives me a clue. I already know the answer will be straight forward but the frustration is that following the very simple and clear instruction in the manual just to make an LED blink has not worked and the trouble shooting only seems to assume that it will so does not offer a solution.

forever hopeful

Steve
 

Attachments

inglewoodpete

Senior Member
Your soldering looks neat. How is the LED connected? Polarity, current limiting resistor?

Going back to your original post, I'm not sure that you understand how the PICAXE software and firmware interwork.

The three modes of operation:
  1. Simulation. The simulator runs in your PC. No download cable or PICAXE chip required.
  2. Run in the PICAXE. Download, unplug the download cable. PICAXE runs stand alone on batteries or other power source.
  3. Run in the PICAXE but tethered to your computer using the download cable. The program runs in the PICAXE but includes the commands "DEBUG" or "SERTXD" to output information to either the DEBUG screen or the Editor's logging terminal (via <F8> key). NOT the simulator's terminal.
 
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premelec

Senior Member
Do you understand that the "darlington outputs" you refer to are only current sinks - i.e. inputs... and the LEDs must connect from V+ to the darlington terminal? The board looks ok...
 
Do you understand that the "darlington outputs" you refer to are only current sinks - i.e. inputs... and the LEDs must connect from V+ to the darlington terminal? The board looks ok...
I believe I have done this but would it be better to remove the link connecting the picaxe power and the Darlington, and use a separate supply?
 
Your soldering looks neat. How is the LED connected? Polarity, current limiting resistor?

Going back to your original post, I'm not sure that you understand how the PICAXE software and firmware interwork.

The three modes of operation:
  1. Simulation. The simulator runs in your PC. No download cable or PICAXE chip required.
  2. Run in the PICAXE. Download, unplug the download cable. PICAXE runs stand alone on batteries or other power source.
  3. Run in the PICAXE but tethered to your computer using the download cable. The program runs in the PICAXE but includes the commands "DEBUG" or "SERTXD" to output information to either the DEBUG screen or the Editor's logging terminal (via <F8> key). NOT the simulator's terminal.
Your soldering looks neat. How is the LED connected? Polarity, current limiting resistor?

Going back to your original post, I'm not sure that you understand how the PICAXE software and firmware interwork.

The three modes of operation:
  1. Simulation. The simulator runs in your PC. No download cable or PICAXE chip required.
  2. Run in the PICAXE. Download, unplug the download cable. PICAXE runs stand alone on batteries or other power source.
  3. Run in the PICAXE but tethered to your computer using the download cable. The program runs in the PICAXE but includes the commands "DEBUG" or "SERTXD" to output information to either the DEBUG screen or the Editor's logging terminal (via <F8> key). NOT the simulator's terminal.
I have been connecting the LED through the bread boar but added a couple of female pins so that I could easily couple and decouple from the board. On the bread board I added the limiting resister.

I have managed to run the simulator on the PC and all seems to indicate correct however I an conscious this only details the picaxe so does not necessarily prove its operation. But I assume the covers your first point.

After this I think I went straight to your point 3 as I connected to the picaxe, using the simulator and ran the program with the board powered and I had a blinking LED on the board in line with the simulator.

I could also download to the picaxe from the PC and the successful download was messaged on screen.

However when I unplug the serial cable I get nothing.

Steve
 

Aries

New Member
After this I think I went straight to your point 3 as I connected to the picaxe, using the simulator and ran the program with the board powered and I had a blinking LED on the board in line with the simulator.
As IP said, the simulator and the Picaxe are totally different and unconnected (in the physical sense) entities. The simulator is a free-standing program that simulates what a properly-connected Picaxe would do. It does not in any way communicate with the Picaxe and, indeed, is often run without a Picaxe or download cable connected.

As I'm still not entirely clear about the various circumstances, can you clarify? Once you have successfully downloaded the program to the Picaxe:

(1) If you disconnect the download cable and power the Picaxe with batteries, what happens?
(2) If you connect the download cable to the Picaxe and power the Picaxe with batteries, but do nothing with simulator or anything else, what happens?
(3) If you do the same as (2) but run the simulator at the same time, what happens?

Can you post your code? If you put it between [ CODE] and [/ CODE] markers (leave out the spaces inside the brackets), then it will format properly.

If a program does not work, then you should include either DEBUG statements or SERTXD statements. These output to the Picaxe editor's serial terminal (PF8 on Windows). You may have to set the terminal speed to match your Picaxe - it's usually 4800 if you haven't done anything special. Put one such statement at the start of your program. Download the program to the Picaxe. Start up the terminal window and then power up the Picaxe. You should then be able to see something in the terminal window. If not, then your Picaxe is not even powering up properly.
 

AllyCat

Senior Member
Hi,
I believe I have done this but would it be better to remove the link connecting the picaxe power and the Darlington, and use a separate supply?
You will need to do that when you want to drive a "string" of LEDs in series (probably about 12 volts for 4-5 LEDs) but that shouldn't be necessary to test just one LED (assuming it's a"normal" 5mm or 3mm indicator LED and not any type of "special purpose" LED).

Like the others above, I'm unsure about you reference to using the simulator (it's a good way to test most software but has no relevance to testing any external hardware). Do you have a multimeter and are you using PE6 or PE5 (neither is essential, just to avoid us making unsuitable recommendations) ?

These are the tests I'd propose: Plug in the programming cable, apply power to the PCB and use the "Check PICAXE type connected" test (PE6 Workspace Explorer). That should confirm the 20M2 is connected and communicating.

Download the program, checking the "status" info in PE6 (some of us prefer PE5 because these messages are clearer). DON'T disconnect the programming cable; Does the LED (connected on the PCB) flash ? Keep the power applied and unplug the programming cable (try both the 3.5mm plug and the USB plug ends separately); Does the LED STOP flashing or go out? If it keeps flashing, then remove the power (battery) for a few seconds and then reconnect; Does the LED START flashing again?

The other test that we often do is to add the following to the top of out programs:
Code:
#no_data               ; This just saves a little time
#terminal 4800      ; This should open the "terminal" window
pause 2000            ; Allows time for the terminal window to open (note sometimes it can become "hidden")
sertxd("Starting",cr,lf)
;  Now put the main program here
Cheers, Alan.
 
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