Jumper T8SG - First TX stock running on Deviation

SeByDocKy wrote: Sorry ... if it's already written in previous posts.... but now can we directly flash the U7E nightly buiild for the Jumper ? No hardware.ini modification ?

You probably want to use one of Vlad's builds. Otherwsie the screen will be upside down. Also one of the sticks would be reversed, and Vlad fixed that too. Not sure about other things

dc59 wrote:

PhracturedBlue wrote:
The problem with not shutting down was also common on the Devo radios. Maybe Jumper copied Walkera's power circuit (which I never really liked).

Hi PB,
Do you have any idea about power circuit improvement? maybe we can ask Jumper to change it !!

I probably need to look at it to see what is there.
The key to the circuitry is that the switch needs o power on the Tx, but should only act as an indicator to allow the MCU to power it off. with deviation this isn't strictly needed, since we manage the filesystem writing pretty well, but it still adds a layer of protection from filesystem corruption.

On the Walkera Tx (as I recall...I would have to go dig up the schematic to be sure), the switch is connected to a capacitor which powers on the Tx and then latches the power circuitry on. When the switch is turned off, this does not disengage the latch, but does trigger an I/O event on the MCU which does a proper shutdown procedure before disengaging the latch and powering off the transmitter. Despite what I said previously, it is pretty elegant, but it is also quite complicated, and can lead to failures (though the most common one is just the crappy switch Walkera used..that would probably be an issue regardless of method used).

Once I have my hands on the Tx, I'll take a look at the design and see what they have done. We could ask if they're willing to provide a schematic, that would be a be a good sign of faith, and make things a lot easier. But just to be clear, I'm not willing to sign an NDA for it....If needed I'll just trace out what I need by hand.

Devo 7e power circuit:
www.deviationtx.com/forum/7-development/...oard?start=100#63244 :


Devo 8s power circuit:

ltwvince wrote:

Moeder wrote: Taking a quick look at the bottom of the PCB it seems clear why it won't run with less than 6V supply: They used a 78M05 linear regulator which has 2 V dropout voltage and run an AMS1117 of the 5V line which needs 1 V differential voltage to supply the 3.3 V line. So depending on the load we'll need a supply voltage of 6.0 to 6.3 V.

Simply replacing the 78M05 with a LDO type (typically 0.2 to 0.5 V dropout) in the same package should probably make it run off 4 x AA.

dc59 wrote:
Any idea for the specific regulator we can get for this replacement? I would love to use 4x AA instead of lipo for TX as I have bunch of Eneloop which I generally use for all my TXs.

I think that at any case we can't use 4xAA batteries with 95*30*16mm battery box. 4xAA battery holder has size: 106x26x17mm.

It's not a good idea, you can damage USB port with rigid adapter. Will be better to use 90 deg. miniUSB extension adapter with short cable. Moreover, it can be glued to back cover or glued into hole in back cover.

Looks nice. What about linearity, output voltage from angle? Also, I do not see any mechanical adjustments, such as tension, braking, centering.

I provided the exact analog of Jumper version "hardware.ini".

At Transmitter config Vibration is "OFF" by default.