Devo 7e + A7105PA + Range mod current draw.

For the A7105 module now connected RxEn to Gnd and TxEn to 3v3.
How to hook up the GIO1 and GIO2 pins?


I am waiting for my 3v3 regulator, when I receive it will post results, it should stop of humming and more power, due to 0.5V. The regulator in devo 7e is a really small one, so can't dissipate when at higher power Tx.

With that wiring let them float.

But where did you find that 3.3V regulator on the pcb? Looking at my pictures
of conversion, I only can see a 78D05L.

see image of Devo 7e, looking at the small size I would say max 100mA.

would not be surprised as flying with clipping regulator, humming devo 7e also cause some unreliability could lead to crash?

Never put regulator parallel, as they will not distribute the load equally. (could work but then must put a Resistor at input sides of each regulator)

replace by a 500ma capable pin compatible replacement? any sugestions?


I ordered a 1117 seperate regulator module.

Yes, the L04A is damn small...
if similar to lp2981, it delivers 250mA and 300 mA peak.

Did you trace pin 3 ( on/off)? To what is this bound?
I did messure 12 μA comsumtion, even the TX is off...

It seem 2 outer pin on top are battery input, left bottom bypass C, right bottom 3v3 out.



I think I just remove the reg, then apply 3v3 just at the Vdd pad near the module. Vin can be taken from the pad just above the cap near the ruglator, gnd can be attached to shield of Tx module.

Then they switch the device via source voltage on.

1. V_IN
2. Ground
3. ON/OFF

---

4. NC
5. V_OUT

Pincount like normal IC.

The next days I will open the TX to inspect this.

Did you measure the current drain with the new wiring?

I doubt that the regulator causes the buzzing sound.
The sound differs clearly from protocol to protocol (e.g. Devo vs. DSM2).
Must be some RF phenomenon.

aMax wrote: With Deviation 4.01 or earlier, it is advised to bind TXEN to VCC and RXEN to GND.
Works well, but when you use DEVO protocol, it seem that the board will not be put completely to sleep ...( or standby, really don`t known)

With the Nightly, it is said to connect TXEN to GIO1 and RXEN to GIO2.
I think, that due to better protocol handling this will save a little
battery power too.

Am I right to assume then it is nightly builds and any final version produced after (4.02 for example) that this newer wiring layout is recommended for?

I changed my wiring today from old to new....
With any Nightly it is highly recommended to use the new wiring.
Even with my old devo7e-v4.0.1-ac4f0b2 firmware, I save round about 100 mA when running into DEVO mode.

I am happy with that result.

Whole TX...........with A7105-D03 on board.

I expected that current consumprtion, was less as humming after wiring GPIO pins was much less.

Did you measure RF output power or did do range tests, any differences?

All working as it was before. Only backyard testing...

Super CP = 1mW no issues flying within 15 meters.
Test: 300 microW <23 meter,100 microW =15 meters (holding antenna sideways)

V911 pro = 3 mW, chassing pigeons high over the top of the roof...
Test: 100 microW < 23 meters (end of my garden) Binding from off to on!
Antenna sideways or pointing to the heli.

The powerrange of the A7105, with that little wire, seem to be better than the
CYRF6936 with the Devo7e antenna.

I have replaced the small hot 3v3 regulator, unsoldered / removed it from the devo 7e board.
Put AMS1117 module connected output just for ease direct to 3v3 point close to module. It gives now a stable 3V3 at any powersetting.


With regards to hum, it is still very softly present, I must put my ear on it.
There is a transistor with 10k at the base, driving the speaker, so it must be noise on the input. I tried a 10nF on the base but did not help. I tried a 10uF on the psu, does not help.

Anyway I'll leave it like this.

With the latest nightly, my battery drain seems to have dropped significantly.. I forgot to turn it off earlier and after 30 mins the battery had dropped only 0.02v or so.

Hey guys,
Sorry to dig up that topic, but i think it's relevant to my problem :
I power my 7e with a 6.6v LiFePo 2s 700mAh battery. It's got the range mod and a A7105 module from a V911 tx, and also the 2x3 switch mod
I found that my batteries didn't last very long, so i checked the current draw of my Tx.
Here are the details :I'm a little concerned that there's always a minimum 0,18 A draw...
I tried with the A7105 module unpowered (desoldered the VDD line) but the results were unchanged...
I'm running nightly v4.0.1-6dd95db (I haven't updated it yet to v5.0 as I understood there were problems with DSM2/DSMX, which are the protocols I use the most)
Oh, and I do hear the hum, which doesn't stop after I push a trim button.

Anyone got an advice on that ? Is there a way I can get the current draw back in the 100mA range as I saw earlier in this post ?

Your wiring seems not to be right for the Nightly. The modules not in use are not in powersave mode..
Thats why the tx nearly uses 200mA....and more.
Additional to that your range mod on the CYRF is not working. There should be at least a difference of 43-46mA from 1 to 100mW .