Final testing

[GMW1988]

On my Final tests many things are working well. Looking at BPSK I noticed the Battery Current (mA) was not showing any values. With Battery (V) I am not sure what RT means. I understand Min. and Max. RT was listed 3.96.

I am unfamilar with the On the Go Cable. It is connected to sound jack. Does this help the CubeSatSim transmit sounds better? The Cubesatim does not have a speaker.

Many of the numbers are negative. A negative acceleration seems odd.
A negative current would show that the Cubesatesim is taking on a charge from the solar panels.

[alanbjohnston]

Hi,

RT means Real-Time, so the last telemetry value received. MAX and MIN are the maximum and minimum values since the last reboot. In BPSK mode, each frame has RT, MAX, and MIN values. In FSK mode, each frame has only RT, with every 32 frames a MAX and MIN is sent.

Yes, the zero current for the battery current isn't right, unless the JST jumper cable isn't plugged into the Battery board. But if that were the case, you would need to be plugged into the USB-C cable in order to run and if that cable was disconnected, the CubeSatSim would immediately lose power and shut down. If it can run on battery, that means the blue INA219 voltage and current sensor on the Battery board U1 isn't working right. You can confirm this with this command:

CubeSatSim/config -v

which will show all voltages and currents.

Also, the zero voltage for the +X, +Y, -Y and -Z panels shows that those blue INA219 boards aren't working either for some reason. On the Solar board, they are: U6, U7, U5, and U8. Check to make sure there are no bridged pins on these blue boards and the jumpers A0 and A1 are set correctly. Also touch up the solder joints on the top and bottom of the PCB in case there are open circuits.

Once you have all of the solar panels reading at least 0.8 Volts or higher, you can try plugging in a solar panel and shining a bright light or sunshine on it - then you will see a current reading for that solar panel.

The acceleration values look fine. It says the CubeSatSim is sitting flat with the -Z side down. If you put another side down and wait 30 seconds, you will get a different set of X, Y, and Z acceleration. A negative acceleration just means that the MPU6050 is upside down.

The gyro rotation values show that they need calibration, as they should read close to zero if at rest (not rotating). Follow these steps to calibrate: https://github.com/alanbjohnston/CubeSatSim/wiki/4.-Main-Board-2#gyro-calibration

Good luck with your testing!

Alan

[GMW1988]

I can see a number of pins on the Solar board that need some soldering work on the underside. I can get those pins soldered.

[alanbjohnston]

OK, great. Make sure you check the soldering on both sides, as each blue board is soldered on the top and the bottom.

I didn't answer your question about the OTG cable that plugs into the micro USB connector on the Pi Zero and the USB sound card. The sound card is used as microphone for the Command and Control (C2C) functionality. The FM transceiver module U6 acts as a receiver, and FM demodulated audio goes through the 2.5mm audio jack J13 and into the microphone 3.5mm jack on the USB sound card. This allows the Pi Zero to run Direwolf on the microphone audio and detect DTMF or APRS packets for Command and Control. For details on how to use C2C, see the Quick Start Guide: https://cubesatsim.org/download/c2c-qsg.pdf

Alan

[GMW1988]

I messed up INA210 DC with the soldering iron. I had to rebuild the Solar Board. The accelerometer I can reaccelerated easily. I am more concerned with the Current not showing again. The Current is listed on a few locations of the Cubesatsim however. I touched up pins on the board with solder on a few spots.

In the photo can you spot pins that may need additional work or any other suggestions to try to get it to work?

Thank you, Gregory

[GMW1988]

[alanbjohnston]

Hi Gregory,

In FoxTelem, for -X, I see a voltage of 0 and a current of 0. This indicates that the INA219 sensor is not seen by the Pi Zero software. I'd touch up these solder joints:

I see voltages and currents for the +X, +Y, and -Y sensors, so I think those ones are good.

For +Z and -Z, I see a voltage but the current is zero (or negative, which also just means zero since the diode prevents reverse current). Assuming you had a working solar panel plugged in and illuminated by sunlight or a strong LED lamp, then this is probably a problem. This could be due to the Vin+ or Vin- pins or the diode, but all the diodes look OK (not reversed or bad solder joints). For +Z, touch up this pin:

I don't see anything on the -Z sensor, but you could still touch up the Vin- and Vin+ pins.

For the Battery, I see a voltage but no current. This could happen if the JST jumper wire on the Battery board isn't plugged in, but if that was the case, the CubeSatSim wouldn't run on battery power at all (with the USB-C cable not plugged in). If it runs on battery power, then it means there is a solder or sensor problem on the Battery board. If you checked the pins on it you might find some bad solder joints.

Good luck! You are getting close!

Alan

[GMW1988]

I took everything apart and touched up pins on the Solar Board and the Battery Board. During the test the Cubesatsim was rotating on turntable, I had a light shining at it. The camera works but I had some troubles with the clip and ribbon came off as indicated in photo which is an easy fix. However, the current still is not showing up. -X Panel is now showing a voltage. I have more work to check my soldering. I might start from scratch on the Battery Board and redo it and work on better soldering from the start. Going back and soldering it was difficult with limited space.

[alanbjohnston]

That’s an improvement!

If you posted closeup photos of the Battery board top and bottom, I might be able to see the bad joints.

Your soldering has probably improved with all the practice, so if you redo the Battery board it will probably show the battery current as well as the voltage.

Alan

[GMW1988]

Thank you for your help. Soldering for a hobby can be a challenge. For those that make a career in soldering - hats off to them. I think I have a good chance to get it fixed after looking at it again but it would be great to get your advice on which pins need more solder.

What do you do if you notice contaminates - possibly burnt plastic on the pins. The pins for the voltage regulator near the battery board on the top side were giving me troubles last night and the solder was not wanting flow on the pins very easy. Often the solder was getting pulled off the pins. I changed the soldering iron tip for a new one and I still had similar results with the solder not flowing that well on those pins.

On the underside the second pin from the left definitely needs more solder as you can see in the photo. Some of pins on the top board may need more solder from what I can see.
Thank you,
Gregory

[GMW1988]

[alanbjohnston]

There are some ugly solder joints, but since you are able to read the battery voltage, they appear to be working. This joint is likely the one that is causing the current reading failure:

The ball of solder on the pin circled in red is unlikely to be making good contact. You need to heat it up again so the solder flows and makes a teardrop shape on the pin. If that doesn't fix it, you could also try touching up the pin to the right of that pin.

As for the other solder joints, it looks like too much heat is being used, which could be because your iron is too hot or you are applying the iron for too long.

I find most soldering issues are caused by dirt - either dirty pins or pads or the iron tip. You should use metal curls to clean the tip of your iron and repeatedly apply solder and clean until the tip of the iron shines like a mirror. If it is black or dull, that means it is dirty and needs cleaning.

The use of liquid flux using a flux pen is also a big help. It can help transfer the heat faster. I'd advise using a flux pen in the future.

Hope this fixes the problem!

Alan

[GMW1988]

Hi Alan,

I tried again with your suggestions with redoing the solder joints and the current is still not showing.
I am thinking it may be time to redo the Battery Board and Solar Board.

I am using lead free solder and I have set my soldering iron to 750 F. I have seen that temperature listed on the internet for soldering irons. What is an ideal setting for the iron for lead free solder? Next, time I use the flux pen also and I also know about keeping the soldering iron tip clean and well tinned is also important.

Thank you,
Gregory

[alanbjohnston]

That all sounds OK.

The other factor is how long the iron is applied to the board. Ideally it is less than 0.5 second. If it is 1st one or more, the heat can damage the PCB and/or the component.

Alan

[GMW1988]

I tried again with improving some of my solder joints on Solar Board and the Battery Board. I put everything back together. Next, I put it on the turntable, had the lamp on. Unfortunately, I was not able to improve things and the results seem odd. I was able to get the Current to show but the numbers changed a bunch. I saw the numbers for Current were moving from a positive and flip to zero, and, negative numbers and were erratic and changed somewhat quickly. Some of the numbers for Current were low and other times it went all up the way up to 299. Resistors should prevent a negative number as you mentioned before and so something is not working with the Battery Board and possibly the Solar Board. The numbers shown look too high at times also.

Also another new issue the I2C Bus 1 and I2C Bus 3 both failed however in the past both of those were working.

Thank you,
Gregory

[alanbjohnston]

Do you see where it says Simulated Telemetry ON? That means all the voltages and currents are simulated (calculated) not from the sensors. This is because the I2C Bus 3 is showing as FAIL. With this bus failed, no valid sensor readings can be taken so simulated telemetry is sent.

Perhaps your boards aren’t plugged properly n correctly - offset by a pin or backwards.

I can’t think of too many things that will do that.

Alan

[GMW1988]

Nothing appears to be plugged in incorrectly. It was not charged recently. Is it possible that a low battery could cause I2C Bus 3 to fail? I am charging it and will see it works better with a full charge.

Thanks,
Gregory

[GMW1988]

Bad news.

Charging the battery did not change the results. I tested the Main Board without the Solar Board and Battery Board and it also failed with the ICU 2 BUS, and ICU 3 BUS.

Something must happened when I was putting it together yesterday. I know it can be a tight fit getting the lid on and I pushed the cables a little too much to get it down I am afraid. The wires for the antenna and the other wires were bunched up and it made it hard to close the frame and something was damaged in the process - I am thinking. However, I am not seeing any damage. Like a broken part on the PCB board.

It appears to be working because the LEDS on the main board light up as it should and it sends the Call sign but the Call sing is not using sensor information. I can see the Digital signal on input on the Ground Station and I can hear it on my radio but the signal must be garbage because no information is sent to the Ground Station.

Any suggestions on what to do at this point. I can try checking things with a volt meter to get more information.

[alanbjohnston]

The two I2C busses are separate, so it is unusual for both to fail at the same time. It could indicate two independent hardware failures. Or it might indicate a common failure, such as a software or hardware issue on the Pi Zero 2.

So you might want to reflash the Micro SD card to reinstall the software.

If you had another Pi Zero or Pi Zero 2, you could try swapping it out.

Other than that, I don’t have any suggestions, sorry.

Alan

[GMW1988]

ICU BUS 3 still is a Fail. Camera and ICU BUS 1 works.

I put in a New Pie Zero 2 in and this did not fix ICU BUS 3.

I reinstalled the software and this did not change ICU BUS 3.

I understand this means I may need to start over with building the Main Board.
I am okay with it these things can happen. I am not exactly sure what happened.
I think it is highly likely something was broken when I closed the Cubesatsim the other day. However, I cannot see any physical damage. Possibly, something was damaged and it went to an electrical issue with the Main Board and it has been zapped or cooked.

I would rather put my energy trying again and apply better soldering practices and be more careful with things. I Know I can make it work.