Smartieparts Backlight problem

cxgiaco · Post by **cxgiaco** » Wed Jun 20, 2012 4:34 am

Hey all,
I just finished upgrading my er9x with the DIY FrSky kit for telemetry. When i flashed the Tx, i could not see any writing on the screen, only the backlight. Once the Tx is unplugged from USB and powered up, the text appears and the controller works properly, but no backlight. I have tried the software settings, to no avail. What am I missing here? did i screw up something in the wiring?
Thanks!
Chris

Post by **Rob Thomson** » Wed Jun 20, 2012 6:15 am

Long press the 'left button'. Then turn on the light in the system preferences.

You can set it to turn on automatically. And off after x minutes!

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cxgiaco · Post by **cxgiaco** » Fri Jun 22, 2012 12:02 am

Turns out i had a dab of hot glue left over on one of the points the the smartieparts board pushes on to. scraped that off, and it fired right up. Telemetry still doesn't work though. I just get "no Data" on the screen. do i need the +5v and ground on the telemetry ports of the tx input connected, (in addition to rxd and txd)?

cxgiaco · Post by **cxgiaco** » Sun Jun 24, 2012 5:04 pm

Still no luck on finding a solution here. I have checked over all my solder points, and am getting +5v on MISO and +.08v on MOSI at the smartieparts board mounts. Tx/Rx work fine for flying the plane, just still no telemetry data whatsoever. red light on sparkfun board blinks once when you power on, and once again when it connects to the rx. after that its just a steady green light. Used Rob Thomson's guide to installation. What is that yellow wire in step 3... is that necessary? Surely someone has a thought on the topic.....

Post by **Rob Thomson** » Sun Jun 24, 2012 6:21 pm

I assume you have got the rx and tx from the rf module connected in the right direction?

Double /tripple check everything. Also... Read the other guides too. The principle in all of them is they same - just done with a different approach. Understanding what needs to be done will help solve the problem.

Also... Do you have any photos of your setup? That will help us help you

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Post by **MikeB** » Sun Jun 24, 2012 7:58 pm

Serial data lines 'idle' in a logic 1 state, so both MOSI and MISO should be at 5V. Rob may have the correct idea that the serial tx and rx signals are swapped. It is always confusing as the TX from the telemetry has to go to the RX on the processor.

Mike.

cxgiaco · Post by **cxgiaco** » Sun Jun 24, 2012 9:23 pm

Thanks for the tips. i will try reversing them. If my MOSI is only .08v, is it possible that I fried the telemetry capability of the module somehow?
Chris.

Post by **MikeB** » Sun Jun 24, 2012 9:42 pm

The Tx module serial data is RS232, this is supposed to withstand any line being permanently shorted to any other so should be fine. You do have a RS232 to logic converter between the processor and the module don't you?

Mike.

cxgiaco · Post by **cxgiaco** » Sun Jun 24, 2012 9:52 pm

So i double-checked the connections, and i definitely had it right, as when i swapped them, the green LED no longer worked. I am not sure why i am not getting +5v on the Rxd terminal, could i have possibly fried something in just that part of the module? If the module is powering the rest of the telemetry osd setup, i feel like it must be internal there, rather than coming from a missed solder joint, unless some command from er9x isn't getting to the telemetry system. Has anyone else flashed with the latest version of er9x-frsky-noht? perhaps i should try an older variant of firmware? Here are the picts of my setup (pardon the hot glue).
Thanks again for all your help, it is much appreciated.
Giaco

Post by **MikeB** » Sun Jun 24, 2012 10:42 pm

Check the voltage on the sparkfun board of the TX signal, where your blue wire connects. It should be around 5V. If it is, and the MOSI is at around 0V, try unsoldering the connection to MOSI and measureing the voltage at the now loose end of the blue wire.

What value resistor do you have in the yellow heatshrink on that blue wire?

I have a concern with your wiring, you appear to have quite long tinned ends to your wires that are not insulated. These could get moved and short to adjacent connections. If possible, I would recommend trying to get the insulation right up to the solder joint, or add some sleeving or heatshrink over the exposed wire.

Mike.

cxgiaco · Post by **cxgiaco** » Mon Jun 25, 2012 12:31 am

MikeB wrote:Check the voltage on the sparkfun board of the TX signal, where your blue wire connects. It should be around 5V. If it is, and the MOSI is at around 0V, try unsoldering the connection to MOSI and measureing the voltage at the now loose end of the blue wire.

What value resistor do you have in the yellow heatshrink on that blue wire?

I have a concern with your wiring, you appear to have quite long tinned ends to your wires that are not insulated. These could get moved and short to adjacent connections. If possible, I would recommend trying to get the insulation right up to the solder joint, or add some sleeving or heatshrink over the exposed wire.

Mike.

Mike/Rob,
After cleaning up my soldering, i found a few things.
1) The voltage at the sparkfun adapter for both MOSI and MISO when the module is not attached are both +5v
2) when the module wires are connected, MOSI drops back down to +0.08v
3) The unplugged outputs from the sparkfun adapter (going to the module) are roughly +.125v and 0v
4) the top and bottom pins of the FrSky module both seem to be ground
5) The resistor inside the heat shrink is a 470 Ohm resistor, per Rob's instructions.

Thanks for you help,
Giaco

Post by **Rob Thomson** » Mon Jun 25, 2012 7:12 am

Initial look at the images looks correct...

Can you get a picture of the other end of the red & yellow wires. Where it plugs into the serial port on the frsky module?

Rob

Post by **jhsa** » Mon Jun 25, 2012 8:01 am

Rob, look a few posts above.. there's a picture of the module..
I'm glad you asked that question.. shouldn't only 2 wires connect to the frsky module? I guess the level converter is getting power from the sp board. so only need tx and rx at the module side I guess.. what is the extra wire? also what module is that? it seems different from mine. At least the serial plug does. I have a DHT..

EDIT: Don't worry about it the brown wire seems not to be used. just saw it...

Post by **Rob Thomson** » Mon Jun 25, 2012 8:20 am

Strange.. they where not showing up in Tapatalk!

Yes.. only two wires go to the module.

Now... what I would check are the following:

1. TX & RX are not swapped on the module side. Simple test.. rotate the server connector 180 degrees!
2. Ground Loop ( And I think this may be the issue - as I recall having this happen once - bat cant see where the leads go on your pics)

Ground Loops (WARNING)
Gruvin found that the Fr-Sky module refused to operate correctly if a ground (GND) wire was connected between the Fr-Sky module's rear RX/TX/GND pins and the level-shifting circuit above. The problem was probably RF energy pick-up through the ground-loop created by having two ground wires -- one where the module plugs into the 9X and the other from the serial data port. Solution: simply do not connect the ground wire as shown as pin-1 on the connector-K2 in the circuit above. Others have since said that they had no such problem. YMMV

Let me know if that helps.

Post by **jhsa** » Mon Jun 25, 2012 8:26 am

But still, the connections don't look quite right on the DHT.. first the DHT should have 4 pins.. second, he should be using the first 2 pins counting from the side of the buzzer.. The first one is RX and the second TX. please check the picture on my post here..

http://www.rcgroups.com/forums/showpost ... ount=17671

João.

Post by **jhsa** » Mon Jun 25, 2012 8:29 am

Yep, maybe turning the servo connector 180 degrees.. and make sure the orange cable is on the first pin from the bottom..

Post by **jhsa** » Mon Jun 25, 2012 8:37 am

Also from the level converter I think that RX Should go to the resistor and then to MOSI. and TX should go to MISO.
The wires seem to be swapped on the level converter.. Rob could you please double check this, or am I not seeing this right?

Also, where is the link to the wiki at the top gone??

Post by **Rob Thomson** » Mon Jun 25, 2012 8:52 am

Wiki link is now on the botton bar on the right

Post by **Rob Thomson** » Mon Jun 25, 2012 8:53 am

jhsa wrote:But still, the connections don't look quite right on the DHT.. first the DHT should have 4 pins.. second, he should be using the first 2 pins counting from the side of the buzzer.. The first one is RX and the second TX. please check the picture on my post here..

http://www.rcgroups.com/forums/showpost ... ount=17671

João.

I was looking for a refence - but could not find one. Thank you

Post by **jhsa** » Mon Jun 25, 2012 8:58 am

Rob Thomson wrote:Wiki link is now on the botton bar on the right

oops, it keeps running away that little b***er..

Post by **Rob Thomson** » Mon Jun 25, 2012 9:01 am

Lol... Am gradually tweaking the layouts and adding features to the forum. Hopefully it will all get clearer over time

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cxgiaco · Post by **cxgiaco** » Mon Jun 25, 2012 4:09 pm

- I have tried swapping the connector on the module, which does have the standard 4 pins. (The photo kind of hides the bottom two pins, and the brown wire is cut on the connector).
- From what i remember, starting at the top, the pins should be Rxd, Txd, +5v, and ground. With the radio on, both the top (Rxd) and bottom (ground) show 0v.
- When flipped, i seem to get the same response, as i still have an Rxd reading 0v, regardless of which was is up. I will try flipping again tonight when i get home, as it appears that you are correct that i have it upside-down.
- I tried Gruvin's suggestion, and the module will not fire up without that ground connected. The way i have it mounted, the pins are awefully close to the radio's grounding plates, i will insulate when i get home as well.

Thanks for all the responses!
Giaco

Post by **jhsa** » Mon Jun 25, 2012 4:28 pm

look at the picture of the link I posted above,, I wrote the TX and RX on the picture according to what was written on the modules shrink. try also to swap the wires at the level converter. the ones that go to the 9x board.

cxgiaco · Post by **cxgiaco** » Tue Jun 26, 2012 3:03 am

SUCCESS! After pulling off the module and re-insulating, i connected to the pins suggested by jhsa, fired up the receiver, and was immediately greeted with that painful scream of "low battery" alarm!. Thanks so much Mike, Rob, and Jhsa for all your tips and advice, i am truely in your debt. I have a feeling i had a few things wrong that all got worked out in the end. Time to install the ardupilot in the sailplane and have some fun!
Giaco

Post by **Rob Thomson** » Tue Jun 26, 2012 3:26 am

Great news. Enjoy

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Post by **jhsa** » Tue Jun 26, 2012 9:07 am

Good that it is working.. well done

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