Padi Stamp v2.2.1, v3.5 (2016/10/08-16:57:18)
#1
My Padi Stamps arrived yesterday for testing;  so, I've got two of these babies soldered-up and ready to go. I decided to make two breakout boards for testing ( one breadboard friendly - pins down ) and one pins up; although, soldering directly to the stamp board would be easy as well putting leads on the board for through-hole mounting.  Obviously the board was designed for easy surface mounting.  Don't be shy about the soldering- it went very smoothly with just a simple 25 watt pen iron. 

   

I am powering the device (padi to the right) with the Elego bread-board PSU ( background far back-right ). The board will take 3v0 to 3v8;  I'm giving the board 3v3 and you'll note that the breakout board has a 100uf decoupling cap ( both boards ).  The cap does not come with the breakout board, but should not be considered optional. I am accessing the uart2 ( Ga4 Ga0 ) from my debian pine board using /dev/ttyS3 and a direct connect via cat5 serial cable (see serial post on this forum) using  sudo screen /dev/ttyS3 38400 .

Using the Serial AT commands I was able to set some GPIO pins on|off, attach to my home wifi AP, and otherwise affirm the correct operation of the Padi Stamp via the serial console alone.

   

In the pic above I'm using the Padi Stamp (2) to drive the amber LEDs in the far background via the serial cable and the command  ATSG=W,PA_5,1,1   ( Write, GA5, ON, OUTPUT )

This unit can be a station STA (default) or an Access Point. In access point mode it contains a web server ! TCP and UDP servers can be easily configured and those connections are easily monitored. 

   

There is a small hole ( visible top left padi ) through which a green comm activity LED shines ( although as you can see its difficult to catch it on ).  This LED flashes rapidly for about one second while booting; also, while executing AT commands blinks quickly with activity similar to any comm LED. 

Keep watching this page;  I will update this photo journal with code snippets , drivers , and test scenarios as they become available. If you have questions about this project feel free to post here, or meet me on the irc to discuss !
marcushh777    Cool

please join us for a chat @  irc.pine64.xyz:6667   or ssl  irc.pine64.xyz:6697

( I regret that I am not able to respond to personal messages;  let's meet on irc! )
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#2
Thanks for sharing. Any plans on using I2C bus of the Padi?
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#3
Can you expand on why the capacitor is not optional?

Thanks
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#4
(10-28-2016, 01:11 PM)cjsieh Wrote: Can you expand on why the capacitor is not optional?

The wifi needs a lot more current than the idle mode.  For instance, Dave could not get his Padi to connect to the wifi AP without putting a more substantial power supply on the Padi... because of the high frequency and the higher current  the regulator supplying the current can't immediately keep up ( under some conditions ) the the capacitor provides the missing energy; the capacitor can react faster than the PSU regulator and it will be more reliable.   If you're not going to be using wifi ( and then what's the point ) you don't need the capacitor.  There are very small .01 pf decoupling caps inside the can of the padi, but the breakout board also needs a board-level decoupling capacitor (imho).

(10-28-2016, 01:02 PM)Traveler Wrote: Thanks for sharing. Any plans on using I2C bus of the Padi?

If I can get the SDK going ( as well the jtag programmer ) I'll be playing with that this weekend.
marcushh777    Cool

please join us for a chat @  irc.pine64.xyz:6667   or ssl  irc.pine64.xyz:6697

( I regret that I am not able to respond to personal messages;  let's meet on irc! )
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#5
(10-28-2016, 01:19 PM)MarkHaysHarris777 Wrote:
(10-28-2016, 01:11 PM)cjsieh Wrote: Can you expand on why the capacitor is not optional?

The wifi needs a lot more current than the idle mode.  For instance, Dave could not get his Padi to connect to the wifi AP without putting a more substantial power supply on the Padi... because of the high frequency and the higher current  the regulator supplying the current can't immediately keep up ( under some conditions ) the the capacitor provides the missing energy; the capacitor can react faster than the PSU regulator and it will be more reliable.   If you're not going to be using wifi ( and then what's the point ) you don't need the capacitor.  There are very small .01 pf decoupling caps inside the can of the padi, but the breakout board also needs a board-level decoupling capacitor (imho).

(10-28-2016, 01:02 PM)Traveler Wrote: Thanks for sharing. Any plans on using I2C bus of the Padi?

If I can get the SDK going ( as well the jtag programmer ) I'll be playing with that this weekend.

Thanks on explaining the important of the capacitor, we will consider to provide into the kit. Looking forward on your next post Wink
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#6
Nice work Mark! Smile 

Interesting to see the PADI Stamp suffers from the same problem the ESP8266 and NRF24L01 wifi/RF modules do... namely lack of a on-board buffer capacitor to tide them over while transmitting... although it isn't that much of a surprise as it's easily implemented on the main board. Looking forward to trying them out (c'mon Australia Post!!) and it certainly sounds like it's a much better beginner experience than the ESP8266 ESP-01s ever were... they were shocking!
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#7
(10-28-2016, 05:45 PM)pfeerick Wrote:  Looking forward to trying them out (c'mon Australia Post!!) and it certainly sounds like it's a much better beginner experience than the ESP8266 ESP-01s ever were... they were shocking!

Its been a very pleasant ( and fun ) experience so far... and looking very promising indeed; hoping you get yours soon, please join on the irc so we can talk through some stuff real-time.   thanks.



I have transferred the entire test setup to a single breadboard - will make viewing and explaining easier.  Again, the power is coming from the Elego rail psu ( regulated and filtered - DCIN is 9v @ 1AMP ) the top rail is 5v for the LED arrays, and the bottom rail is 3v3 for the Padi Stamp vcc. 

Everything can be found here:

   

We have six (6) 'free' GPIO pins by default :  GA5  &  GC0  thru  GC4

The GPIO pins are known by their port designation for the purpose of AT commands: PC_0 = GC0  ;  Px_y = Gxy

To turn on GPIO GC1 (red in the pic) : ATSG=W,PC_1,1,1    (see the AT command sheet for details)

To turn off GPIO GC2 (yellow in pic) :  ATSG=W,PC_2,0,0 

To read an input pin GC0  (switch in pic) :  ATSG=R,PC_0,,0,1   (see AT command ref;  using an internal pullup )

These GPIO pins  GA5 & GC0 - GC4  can be controlled via serial console from the pine board using python;  codes will be coming soon;  but very easily. In a future post we'll see how to control the GPIO pins via wifi from the pine board. The idea is to integrate the Padi Stamp into the PineA64 configuration as an extension for MCU real-time functionality while the PineA64 is then free to handle analytics and high-level control functions. There are many science apps or robotics apps where this might be very helpful.
marcushh777    Cool

please join us for a chat @  irc.pine64.xyz:6667   or ssl  irc.pine64.xyz:6697

( I regret that I am not able to respond to personal messages;  let's meet on irc! )
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#8
(10-28-2016, 09:33 PM)MarkHaysHarris777 Wrote:
(10-28-2016, 05:45 PM)pfeerick Wrote:  Looking forward to trying them out (c'mon Australia Post!!) and it certainly sounds like it's a much better beginner experience than the ESP8266 ESP-01s ever were... they were shocking!

Its been a very pleasant ( and fun ) experience so far... and looking very promising indeed; hoping you get yours soon, please join on the irc so we can talk through some stuff real-time.   thanks.



I have transferred the entire test setup to a single breadboard - will make viewing and explaining easier.  Again, the power is coming from the Elego rail psu ( regulated and filtered - DCIN is 9v @ 1AMP ) the top rail is 5v for the LED arrays, and the bottom rail is 3v3 for the Padi Stamp vcc. 

Everything can be found here:



We have six (6) 'free' GPIO pins by default :  GA5  &  GC0  thru  GC4

The GPIO pins are known by their port designation for the purpose of AT commands: PC_0 = GC0  ;  Px_y = Gxy

To turn on GPIO GC1 (red in the pic) : ATSG=W,PC_1,1,1    (see the AT command sheet for details)

To turn off GPIO GC2 (yellow in pic) :  ATSG=W,PC_2,0,0 

To read an input pin GC0  (switch in pic) :  ATSG=R,PC_0,,0,1   (see AT command ref;  using an internal pullup )

These GPIO pins  GA5 & GC0 - GC4  can be controlled via serial console from the pine board using python;  codes will be coming soon;  but very easily. In a future post we'll see how to control the GPIO pins via wifi from the pine board. The idea is to integrate the Padi Stamp into the PineA64 configuration as an extension for MCU real-time functionality while the PineA64 is then free to handle analytics and high-level control functions. There are many science apps or robotics apps where this might be very helpful.
BRAVO !!!
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#9
   

The pic above shows my test setup for driving the Padi(s) in parallel from the pine board using the cat5 serial cable.  The top padi is controlled on /dev/ttyS2,  and the bottom padi is controlled on /dev/ttyS3. 

This is an example of 'why' the caps ( one on each breakout board ) are called decoupling caps. Both of these boards are on the same power rail.  Each cap 'decouples' the padi boards from each other so their high frequency | current  does not affect the operation of the other board!  

The top padi is driving the yellow LED array, and the bottom padi is driving the red LED array. Both arrays are being driven via 2N2222 transistor to handle the current. The Elego psu has no trouble handling the psu requirements and the same 'screen' ( or minicom ) interface(s) display can handle both padi(s) nicely from the same pine board controller.

note:  incidentally , z-wave modules could be hung off of the cat5 cable as well;  also, the padi stamp could be used in place of a z-wave module for several kinds of home automation.
marcushh777    Cool

please join us for a chat @  irc.pine64.xyz:6667   or ssl  irc.pine64.xyz:6697

( I regret that I am not able to respond to personal messages;  let's meet on irc! )
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#10
I'm still working out-of-box with the twin Padi Stamps shown configured in parallel in the above pic -- the top padi (pins up) on pine board /dev/ttyS2, and the botton padi (breadboard friendly, pins down) on pine board /dev/ttyS3. 

The minicom screen outputs below depict the output from the AT confirmation (modem init) command, and the ATWS ( wifi scan command ).  These outputs are completely out-of-box tests showing the sensitivity of the wifi antennae and receiver. Access Points 1, 2, &3 are at various locations throughout my home;  the rest are in the neighborhood. Both readings were taken within a minute on the same day, and the test configuration is as depicted above. 

The top padi is slightly more sensitive ;  however, overall both units are performing very well-- much better than expected; I am very impressed with these devices.

Code:
Port /dev/ttyS2, 16:29:00

Press CTRL-A Z for help on special keys              
                                                   
AT                                                  
[AT] OK                                              
                                                   
# ATWS                                  
                                       
#                                        
AP : 1,SouthTower,7,WPA2 AES,-32,10:0d:7f:67:eb:22
AP : 2,Tower_RPT,7,WPA/WPA2 AES,-48,f8:7b:8c:09:55:d5
AP : 3,Bridge_RPT_2g,7,WPA/WPA2 AES,-61,f8:7b:8c:1c:69:f1
AP : 4,sunsparc,5,WPA2 AES,-71,e4:f4:c6:1d:70:ac
AP : 5,Magic Kingdom_EXT,2,WPA2 AES,-75,44:94:fc:8c:90:82
AP : 6,TrotterPlex,10,WPA/WPA2 AES,-79,48:f8:b3:de:4b:34
AP : 7,JFJKFJ,6,WPA/WPA2 AES,-85,00:1f:33:24:8d:ac
AP : 8,Magic Kingdom,2,WPA2 AES,-89,a4:2b:8c:80:e5:c1
AP : 9,SurveillanceRST,6,WPA2 AES,-91,40:16:7e:59:0f:20                        
AP : 10,NETGEAR221,10,WPA2 AES,-91,50:6a:03:a4:b9:34                            
[ATWS] OK                                                                      
                                                                               
#

Code:
Port /dev/ttyS3, 16:28:14

Press CTRL-A Z for help on special keys              
                                                   
AT                                                  
[AT] OK                                              
                                                   
# ATWS                                  
                                       
#                                        
AP : 1,SouthTower,7,WPA2 AES,-38,10:0d:7f:67:eb:22
AP : 2,Tower_RPT,7,WPA/WPA2 AES,-54,f8:7b:8c:09:55:d5
AP : 3,Bridge_RPT_2g,7,WPA/WPA2 AES,-61,f8:7b:8c:1c:69:f1
AP : 4,sunsparc,5,WPA2 AES,-75,e4:f4:c6:1d:70:ac
AP : 5,Magic Kingdom_EXT,2,WPA2 AES,-85,44:94:fc:8c:90:82
AP : 6,SurveillanceRST,6,WPA2 AES,-87,40:16:7e:59:0f:20
AP : 7,TrotterPlex,10,WPA/WPA2 AES,-89,48:f8:b3:de:4b:34
AP : 8,Magic Kingdom,2,WPA2 AES,-95,a4:2b:8c:80:e5:c1
AP : 9,JFJKFJ,6,WPA/WPA2 AES,-95,00:1f:33:24:8d:ac                              
[ATWS] OK                                                                      
                                                                               
#

note: the lower the dB the weaker the signal ie. -32 is a stronger signal than -95; -87 is a stronger signal than -95.
note: both units have been idling primarily all weekend for "burn in" test... ie, they have been powered up 24x7 without failure or glitch.
marcushh777    Cool

please join us for a chat @  irc.pine64.xyz:6667   or ssl  irc.pine64.xyz:6697

( I regret that I am not able to respond to personal messages;  let's meet on irc! )
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