Devo 12s 3in1 / 4in1 RF module neat installation.

NathanBarguss wrote: organising shipping via. www.taobaofocus.com I managed to get hold of the 4-in1 Devo 10 daughter board. (It’s the new 13 pin version of the 4-in-1 and is the Y220.00 ‘blue’ option here: item.taobao.com/item.htm?id=27232304992 )

This information enabled me to place an order without having to decipher Chinese... Thanks a lot!

To finish off my 3in1 install I added a second 3.3V regulator. As discussed in this thread and others, the onboard 3.3V regulator is pushed past its design specifications with the addition of RF modules, which can cause overheating of the regulator, unexpected shutdown, and premature failure. Although bad stuff can happen, it doesn’t seem to happen often, and it appears that most people just take their chances with the onboard regulator. For peace of mind I decided to add a second regulator to run the additional modules, while leaving the onboard regulator to do its intended job.

Originally I planned to use an AMS1117 based linear regulator from Banggood since it’s dirt cheap and simple, but with all the bad publicity surrounding fake AMS1117 chips having a failure mode of placing the supply voltage on the output pins, and their relatively high minimum working voltage (4.5V), I decided to go with a Pololu D24V5F3 switching regulator. Dropout voltage at the current required will probably be around 0.25V, so the minimum working voltage is around 3.55V. I use NiMh batteries and don’t discharge them below 1 to 1.1V per cell, so the regulator will always have adequate voltage.

www.banggood.com/4_5V-7V-to-3_3V-AMS1117...odule-p-1038726.html

www.pololu.com/product/2842

Inputs to the regulator are tied directly to the battery, with SHDN (shutdown) connected to the output of the FET that supplies power to the onboard linear regulator. I removed the 100k SHDN pullup resistor (R3) from the Pololu regulator board to ensure proper shutdown when the TX is turned off. This method has the least impact on the original circuit design, insures that the switching regulator won’t draw surge current through the FET, and it reduces the possibility of introducing noise into the original power supply circuitry. Are these precautions necessary? Possibly not, but it was easier to take measures to avoid potential problems than it was to test for them.

NathanBarguss wrote: So a quick update, from my build thread doctortim has suggested that the poor performance I'm seeing (Lag on the StmaX4) could be linked with counterfeit nrf24l01's... Has anyone had experience of this?

I'm going to take the top off my 4-in-1, but if its a case that they're using 'bad' fakes, makes it kinda dissapointing if that's the reason for the poor performance with auto-ack.

Reference:
forum.mysensors.org/topic/1153/we-are-mo...fakes-are-emerging/7

Have you tried using the 4 in 1 with other nrf24l01 based protocols which do not use AA, e.g. hisky? If we don't see any delay for other protocols, it is probably still a LNA control issue.

For AA to work, the PA/LNA has to be switched into LNA mode to receive ack's while nrf24l01 is not sending. Normally that is controlled by hard wiring between nrf24l01 and PA/LNA. The 4 in 1 control has to know how to handle that on a shared PA/LNA.

Anyway are you or the supplier going to replace the nrf24l01 on board?

Let's know if a good nrf24l01 resolves the issue. Perhaps you should swap the RF chip of the 4 in 1 with your working standalone module.

Would you be willing to keep me posted on your progress? I just received my devo f7 and would like to add the 4:1 rf module in the same fashion as yourself.

Did you manage to get this project working? It seems like the best option to me. I just got the f7 and am hoping to mod it like the one shown above

Where or how are the orange and black wires connected?

The orange and black wires supply power and ground to additional RF modules. In my case they connect to a 3in1 module. Install RF modules as normal, except use the black and orange wires to power them instead of deriving power from the main TX board.

Thanks for that, exactly what I wanted to know.
One more question, I have a different model pololu www.pololu.com/product/2118 .
Should I also remove the resistor on the shdn - vin?

I have plenty of cheap AMS1117 3.3V modules. And a load of adjustable modules. Usually I use them in series, to not stress the linear regulator.

Cheap / fake modules are listed to have input 4.5-7V. And the AMS1117 is 800mA max.

The other cheap option is swicthing step-down modules like these for $1.35 - They are 1.5A cont, 3A max.
www.ebay.com/itm/9V-12V-19V-To-3-3V-DC-D...b:g:uZAAAOSw4s9Xksw8

Or just test the 3.3V regulator with a load.

Gerry, your Pololu has the same shutdown circuitry as the one I used, including the 100k pullup resistor that should be removed for proper shutdown. It is R6 in the schematic and you will have to follow the traces on the board to find it. One word of caution. Since your regulator is adjustable, be sure to check and adjust the output voltage before connecting it to any RF modules. I did the same when installing my regulator even though it's not adjustable. Connect the inputs, turn on the radio, check for proper output voltage, turn the radio off and confirm that the regulator shuts down, disconnect the batteries, then connect the output wires to the RF module.

Povlhp, I consider a minimum input voltage of 4.5V to be too high for a device that runs off of four NiMh cells since a low battery condition could cause sudden loss of signal, and possible loss of a model. Each cell would have to stay above 1.125V or the output voltage would drop. I typically run my NiMh cells down to 1 to 1.1V per cell. This is why I ruled out the use of a cheap AMS1117 regulator.

The switching supply you linked to doesn’t have a shutdown feature so it can’t be wired the same way as the Pololu. Also, I wanted to avoid cheap no-name switching regulators for this project. They are fine for some applications, but I wanted a regulator from a known company with a good track record and Pololu fits. When buying a single regulator the price difference isn’t that great, at least here in the US. The eBay regulator with shipping is $3.84. The Pololu I purchased with shipping was $8.90. It’s a big difference percentage wise, but in terms of money it’s $5.06 more. I prefer to spend the extra five bucks for a name brand with schematics and technical specifications online.

Should i buy the the 3in1 or 4in1 for my Devo10 thats been collecting dust?
I'm about to place a order from banggood as i need a new fpv camera anyway.

Xermalk wrote: Should i buy the the 3in1 or 4in1 for my Devo10 thats been collecting dust?
I'm about to place a order from bang good as i need a new fpv camera anyway.

I don't think we can answer that for you. Identify your objectives and perhaps the answer to your question will become self-evident.

I don’t have a Devo 10, or a 4in1 module, so I have no personal experience. What I know has come from the comments of others. If I’m wrong about something, then I welcome corrections and comments.

The single biggest advantage of a 4in1 is that only one antenna is required. If that’s something you want, then maybe a 4in1 is for you. If you don’t care about that feature then a 3in1 might be a better choice. There is a Devo specific daughter board for the 4in1, but I don’t think that Banggood sells it. Instead, you need to purchase directly from the manufacturer which can be a complicated process. One of the forum members, valley_nomad, ordered extra modules from China and has kindly offered to sell them to other members, so that might be an easier way to get one. I believe that someone has a different Devo board in development.

www.deviationtx.com/forum/7-development/...dule?start=760#52438

The 4in1 module is rather new and is still being revised. One possible remaining issue could be the long antenna trace. The 3in1 design appears to be more stable and I’m not aware of any current issues. Also, it’s available from Banggood. Personally, I would shy away from the 4in1 until a good track record is established. My interest in the 4in1 is not for a Devo, but for my Taranis. Hopefully that project continues to move forward and matures.

Arnold wrote:

Xermalk wrote: Should i buy the the 3in1 or 4in1 for my Devo10 thats been collecting dust?
I'm about to place a order from bang good as i need a new fpv camera anyway.

I don't think we can answer that for you. Identify your objectives and perhaps the answer to your question will become self-evident.

Just read through the entire thread, most of it going way over my head.
But ill skip getting it from banggood for the moment. And instead wait for the 4 in 1 with the devo10 board.

Unfortunately im not in the US , so im unsure if valley_nomad would be willing to sell one of his extras to me.

NathanBarguss wrote: I’m lucky that I work for a large household name computer games company, and we have a translations department. Talking with them, and then organising shipping via. www.taobaofocus.com I managed to get hold of the 4-in1 Devo 10 daughter board. (It’s the new 13 pin version of the 4-in-1 and is the Y220.00 ‘blue’ option here: item.taobao.com/item.htm?id=27232304992 )

Looks like the 'blue' option for Y220.00 doesn't exist anymore....

and the option is back...

Thanks robpur,
What you have described is pretty much what I would have done.

robpur wrote: ...One possible remaining issue could be the long antenna trace...

I just range tested the 13 pin 4-in-1 I ordered from Taobao on July 20th. I tested this in a Devo 10 (black model with the old antenna) and I also tested a 7E with the range mod. I used DSMX and a MCPX V2 that was stationary and at eye level, and I used 100uw power. The 7E lost contact at 31M, and the 4-in-1 lost contact at 33M.

I tested both multiple times switching back and forth between 100uw and 300uw and always re-established the link instantly when switching to 300uw and lost it instantly when switching back to 100uw. Taking 2 steps forward / backward also re-established and then broke the link on both multiple times.

So it looks like the 4-in-1 range is pretty good and maybe the antenna trace isn't an issue, at least at low power DSMX.
Does anybody know if the long trace may effect higher power differently than lower power?

BirdBarber wrote: So it looks like the 4-in-1 range is pretty good and maybe the antenna trace isn't an issue, at least at low power DSMX.
Does anybody know if the long trace may effect higher power differently than lower power?

Is shielding the daughterboard with RF shielding tape an idea?