TX data sent to RX with nonsense

[bmco2n]

Hola Adafruit,
I’ve made a little progress on my problem with the Xbee/Arduino sending nonsense to the Xbee/computer. It still sends the data, too, but only on a condition that I might be related to the “avrdude sync error” when uploading. It seems to narrow down to the Arduino reset pin in contact with the bipolar transistor. As I mentioned, the transistor pulls the AD3 volts on the Xbee low, from a constant 3.3V to 0.18V and the current from 145 to < 65. In this arrangement, only nonsense is sent to the Xbee/Arduino. However, if the transistor is bypassed, sending the 3.3V directly to the Ard reset, the data is sent OK , but I still have the problem of the nonsense. A picture of the arrangement is shown with the AD3 wire feeding the the Ard reset through the transistor. The PIR sensor was removed for clarity. Note: The picture inserted into the word file didn't fly with the this text. Any suggestions?
The wire from the collector is soldered to the reset place, but it’s the same if the collector goes to the analog header reset pin. I still don’t understand the transistor set-up shown here, ala Ladyada>tutorials>Xbee>connect. But the real problem is that the 3.3 voltage on AD3 is constant. If the Xbee/comp is resetting on and off for send/receive, it isn’t happening.
Thanks again for everything.

[adafruit_support_bill]

To post a photo, use the "upload attachment" tab below the message edit box.

[bmco2n]

Hola Adafruit,
I’ve made a little progress on my problem with the Xbee/Arduino sending nonsense to the Xbee/computer. It still sends the data, too, but only on a condition that I might be related to the “avrdude sync error” when uploading. It seems to narrow down to the Arduino reset pin in contact with the bipolar transistor. As I mentioned, the transistor pulls the AD3 volts on the Xbee low, from a constant 3.3V to 0.18V and the current from 145 to < 65. In this arrangement, only nonsense is sent to the Xbee/Arduino. However, if the transistor is bypassed, sending the 3.3V directly to the Ard reset, the data is sent OK , but I still have the problem of the nonsense. A picture of the arrangement is shown with the AD3 wire feeding the the Ard reset through the transistor. The PIR sensor was removed for clarity.
The wire from the collector is soldered to the reset place, but it’s the same if the collector goes to the analog header reset pin. I still don’t understand the transistor set-up shown here, ala Ladyada>tutorials>Xbee>connect. But the real problem is that the 3.3 voltage on AD3 is constant. If the Xbee/comp is resetting on and off for send/receive, it isn’t happening.
Thanks again for everything.

021a.jpg (458.2 KiB) Viewed 980 times

[adafruit_support_rick]

I can't tell from the picture: Are you using different power and ground for the XBee than you're using for the Arduino?

I don't think your transistor circuit is doing what it's supposed to do. It's not supposed to pull 3.3 down. It's supposed to use the XBee reset signal to switch the Arduino reset to ground.

Look at the schematic again. The XBee reset goes thru the cap to the base. The emitter goes to ground, the collector goes to the arduino reset. There's also a 10K pulldown on the base. I don't see any resistors in your picture.

[bmco2n]

Hi Arduino,

Thanks for staying with me. Really sorry about the photo. The resistor was in the photo, but hidden by the transistor. I caught this and made a better photo, which I can't attach for some reason. I get the error message, "The file you are trying to attach is invalid". It was a 450K jpeg file I cropped and saved from Photoshop Elements and I'm looking into this. Meantime, to answer your questions:

The 10K resistor is present, connecting the transistor base to the emitter to ground. In the pic, the emitter is on the right and the collector is on the left. The jumper you see across the breadboard gap goes to ground on the other side. The 3.3 volts from the Xbee AD3 wire is sending to the trans base via the capacitor, all of which tested OK. The trans collector is connected to the Arduino reset and shows 5V, because the Ard reset is at 5V when unconnected, which I didn't expect.

The 5V power and ground from the Arduino is connected to the breadboard at the bottom left of the picture and sends power and ground to the other Xbee side via jumpers underneath the UNO. The Xbee blinks green, so it's getting power. I'll send you a good picture when I figure out what the message means.

Cheers and thanks again

[bmco2n]

Dear Counsel,
I'm stil trying to get you the better picture. Nothing happens when I attach a file so far, but still trying on this post. Tried to attach, but my "message contains too few characters" so far, so I 'm adding characters. This file is a jpeg with less than 400Kbytes, resized to 4 X 2.8 inches. If I preview, I get a huge zoom that can't be seen. If I click on the "place inline", only the name of the file appears on this space.

[adafruit_support_rick]

Did you install the jumper between RTS and D3 on there XBee, as shown in the tutorial?

The reset line from the XBee is active high. I think you're saying that it's always at 3.3. So, if you've got 3.3V going to the base of the transistor, then the transistor will always be on and it will always be asserting the Arduino reset signal.

However, if the transistor is bypassed, sending the 3.3V directly to the Ard reset, the data is sent OK , but I still have the problem of the nonsense.

I don't understand what you mean here. The data is OK, but it's nonsense? Can you clarify this a little? What sort of nonsense are you seeing?

[bmco2n]

Dear Advisor,

Here is the X-CTU terminal output and what I meant about "nonsense". The fourth line down is the data, "1.34, 0" (1.34 minutes and no motion) and the previous lines are "nonsense". I hit the reset button on the Arduino to show "Hello World" and the data the third line below showing .05 min and "1" for PIR motion detected. What I'm trying to achieve is a column of data to get into Excel for plotting and this display prohibits that.

Thanks

.~.....0......;~.....0......;~.....0......;~.....0......;~.....0......;~.....0......;~.....0......;~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~.....0......;~.....0......; 1.34, 0
.~.....0......;~.....1......:~...../......<~...../......<~...../......<~.....0......;~.....1......:~...../......<Hello, world?
.~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......< 0.05, 1
.~...../......<~...../......<~...../......<~.....0......;~...../......<~.....0......;~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......< 0.11, 1
.~...../......<~...../......<~...../......<~...../......<~.....0......;~.....0......;~.....0......;~.....0......;~...../......<~...../......<~...../......<~...../......<~...../......<~...../......< 0.17, 1
.~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<~...../......<......

[bmco2n]

Hi again -- Forgot to answer your question. Yes, the RTS and D3 are connected on the Xbee/computer adapter with soldering, as per the tutorial. These are not connected on Xbee/Arduino adapter, which has the AD3 soldered to the line that feeds the transistor base via the capacitor.

[adafruit_support_bill]

Can you post a diagram of your whole system? I doubt that the 'nonsense' has anything to do with the reset transistor. Make sure that your transmitting XBee is not in 'line-passing' mode.

[bmco2n]

Dear Adafruit_assistance

I am really thankful for your continued attention to my problem, but I think I'll quit this. I did stop the I/O line passing some time ago by using FF, canceling the FFFF instructed in the Ladyada>Xbee>connect tutorial. The avrdude sync error started happening again. I thought it had something to do with uploading when the Arduino reset was plugged into the transistor collector, but now it happens anyway. Arduino troubleshooting wasn't helpful. I've looked into the forums on this error message and the consensus is that nobody knows what to do about it, after so many posts.

Your efforts in open source and tutorials are heroic and hugely appreciated, but for the unwashed like myself, there are so many permutations of unknown problem sources:

Soldering is tricky---I bought 3 datalogger kits, out of my failure to get the first to work. Finally got two to work after construction by consulting the published circuits but they still won't light up the LEDs. Got the first one to work by grounding the SD card holder. Likewise, 3 Xbee adapters and all continuities were OK checked for all pins, but who knows? One out of three Xbees I bought won't let the adapter LEDs light up on the FTDI USB cable.

Who knows that the X-CTU has to be removed and installed frequently? It starts displaying the same serial number with different Xbees and says OK for connection with Xbees that can't connect. One must always check to see for the right serial #, otherwise lots of wasted time ensues.

Lots of things did work at first: I had great Xbee communication with the Ping distance sketch, temperature, etc. Perhaps this is where the components were injured. I really learned soldering skills, armed with paste flux, especially with those tiny wires to the RGB led belts. I learned a lot and am most grateful to all of you advisors.

Cheers