Arduino Flip-Flat Problem Solved

Maybe you might find this information useful if you’re thinking of making a light panel?

Some time ago I made an Arduino Nano based Flip-Flat style light panel for my Skywatcher.

It is based on the description given in the CloudyNights post DIY Alnitak flat panel - ATM, Optics and DIY Forum - Cloudy Nights and uses the firmware from GitHub GitHub - jwellman80/ArduinoLightbox

From what I can gather it’s quite popular & well used solution in various forms. I just added some code for my servo & made a quick release clamp to fit the dewshield. But it had a problem.

Before purchasing Voyager a few months ago I used it for a long time with a previous solution but it was always very slow to connect for the first time, several seconds or maybe a minute. But eventually it would connect. After connecting for the first time, subsequent connections always worked normally; as long as I did not turn the power off!

Now of course with Voyager I neede to resolve the problem because it simply times out as per the image below, which make using it more complicated.

If I try to connect a second time I see this:

If I restart Voyager it connects fine but that’s no good for achieving automation. And as you can see the Arduino appears fine in my device manager:

Dev manager COM14

Eventually I found the behaviour was down to the version of my Nano which uses the CH340 USB chip. I’m sure a genuine Nano would be fine. Or maybe a different driver but I did not find one that resolved the problem.

So my solution (having soldered my Nano in place) was to use the Nano’s TTL serial RX & TX connections with a USB to TTL converter by DS-Tech DSD TECH Official Website: DSD TECH USB to TTL Serial Converter CP2102 with 4 PIN Dupont Cable Compatible with Windows 7,8,10,linux,Mac OSX

Dev manager COM11

Now in Voyager my Flat device connects instantly first time, every time.

So I guess the moral of the story is beware of copies - not every device is compatible with every application!

Initially I encountered the same connection issue with my DIY flatpanel controller. It is caused by an automatic reset triggered by the DTR signal whenever you connect USB serial to the Arduino Nano.

I solved the issue (meanwhile on several different projects) by adding a 10uF capacitor from RESET pin to ground. As the automatic reset is useful when reprogramming the Arduino, I put a jumper between capacitor and reset pin. In normal operation the jumper is closed (prevents from reset on connect), during software development/reprogramming it is open.


Voyager have a timeout of 15s on serial communication and dont know which driver you are using.
The OS APIs is always the same for all applications Voyager included. A timeout on serial port after 15s always means an hardware problem.

Thank you for the info.

All the best

Hi RTJoe,

Many thanks indeed for taking the time to comment on my post.

Until I read your explanation I had no idea why the Nano was resetting & initially thought it was a fault with that particular Nano.
But when I found that both my flat panel controllers behaved in the same way I concluded that two devices with exactly the same fault was too much of a coincidence.

After some research I opted to use the serial RX\TX connection instead of the USB connection. Obviously this meant adding a USB to TTL converter.

Following your explanation I now know why this works but your solution is much simpler, easier to impliment & cheaper too.

So today I’ve removed my USB/TTL converters, applied your fix & gone back to using the USB connection. I’m delighted to confirm that it does indeed work perfectly. In fact I’m watching my DragScript gather images right now. I shall re-use the converters on other projects I’m sure.

I would like to know where you found the diagram in your post though, as I’ve not managed to yet.

Once again thanks for sharing your very useful information.

Best wishes

Hi Martin,

glad to hear that this fixes your issues with the Nano.

The diagram is part of the schematic of my DIY controller for a motorized Flatfield Panel. It’s perfectly working with Voyager. You can find the schematic here and this is the link to the whole project:

Clear Skies,

Hi Joachim,

That’s a very nice & professional project. Thank you for sharing.

Best wishes