[xfce]

I am designing oplink+bt , oplink is compatible with RFM22(100mW max) and RFM23(1W max).

3D PCB as below

top


bottom


and real PCB


Now I am testing them, after all test OK, if someone like, i will make a batch

[f5soh]

Hi,

Some remarks about pcb traces around the holes/screws, especially if they are for Vcc this is not really fine.
BT module will have the antenna in one border without ground in PCB.



Adding a connector around the right edge will be fine for a JR module, using a straight SMA connector.
Please also consider adding big pads for soldering Vcc input wires directly.

Is the 5V regulator still ok with RFM23BP (1W) / 550mA @ 3S ?

[Mateusz]

That is really cool idea, also some suggestions

• Inverter for FrSky telemetry ? I think F303 which is pin-compatible with F103 has inverter in MCU, but not sure how easy to run Oplink firmware on F3 ?
• Does it fit into standard Taranis module JR case ?

[TheOtherCliff]

Will the HC05 antenna have reduced range, because it is close to ground plane, etc in main board?

Will RF from HC05 antenna cause problems in main board?

[f5soh]

Will the HC05 antenna have reduced range, because it is close to ground plane, etc in main board?

From some priced bluetooth module, here is guidelines.
This just make sense for optimal antenna radiation, as already reported.

Will RF from HC05 antenna cause problems in main board?

Likely not, power levels are really low (~3mW max)

[Brian]

I like the board with the same comments as others have made. I would also suggest using an F3 MCU, since it can do inverted UART, etc.

I'm currently designing a nano-oplink with the intent of using it as a receiver on nano-quad builds. It's just slightly bigger than the rfm22b module, and I plan to put an F3 on it.

[xfce]

Thanks all
I have tested , all functions are OK
BT can work about 10 meters, I think it's OK.


And LP2GO is wonderful.


test video


1)The trace are VCC, and I will remove them next version,as the first version is a two layers PCB, maybe changed to 4 layers;

2)USB socket will moved away from BT module's antenna;

3)about JR module connector,  does it just use 2.54pitch? or I think the oplink's Flexi port is OK

4)it is a standard SMA footprint, so 90° or 180° SMA broth are OK;

5)next version can add Vcc PAD;

6)I can use F303, but could you please develop the firmware;

7)for the JR case, you can give me the PCB outline, i can try to redesign the PCB just fit the JR case,
or i can give the PCBA's 3D module in .stl file , could anyone  help me to design a 3D printed case

[Brian]

Attached is a design that I started a while back. I believe the dimensions are correct, but it was never built. It was built for a standard case that I found available, but I don't remember the part number off hand. If I find it I'll post it.

[xfce]

I have just use FreeCAD design a case, FreeCAD is simple and wonderful.
will print later

bottomcase


topcase


update: It's done

[ekrem]

really  good project

but I dont understand why need q1 and q2 transistor

[TheOtherCliff]

I don't have software to view board designs.

If you could post a schematic that includes the transistors you are talking about, I might be able to help.

If it is associated with MainPort, it may be an SBus inverter, else maybe a level shifter like from 3.3V to 5V.

[ekrem]

hi TheOtherCliff
 
original project  schematic file attached

[jdl]

I guess the q1 and q2 are meant to invert signals logic when RFM23BP module is used. The original project schematic is not wrong or inoperational but these inverters are not needed if you connect RFM23BP exactly the same way (pin-wise) as RFM22B. Pins 3 & 4 on both modules have swapped names (TX_ANT, RX_ANT on RFM22B vs RX_ON, TX_ON on RFM23BP) but their truth tables are also changed respectively to ensure the compatibility:

For RFM22B:

pin 4	TX_ANT:	Tx Antenna select input pin, When RFM22 is TX state,TX_ANT should be = 1, RX_ANT should be = 0
pin 3	RX_ANT:	Rx Antenna select input pin, When RFM2 2 is RX state,RX_ANT should be = 1, TX_ANT should be = 0

For RFM23BPS:

pin 3	TX_ON:	Tx ON select input pin, When RFM23BP is TX state,TX_ON should be = 0, RX_ON should be = 1
pin 4	RX_ON:	Rx ON select input pin, When RFM2 3BPS is RX state,RX_ON should be = 0, TX_ON should be = 1

[ekrem]

I guess the q1 and q2 are meant to invert signals logic when RFM23BP module is used. The original project schematic is not wrong or inoperational but these inverters are not needed if you connect RFM23BP exactly the same way (pin-wise) as RFM22B. Pins 3 & 4 on both modules have swapped names (TX_ANT, RX_ANT on RFM22B vs RX_ON, TX_ON on RFM23BP) but their truth tables are also changed respectively to ensure the compatibility:

For RFM22B:

pin 4	TX_ANT:	Tx Antenna select input pin, When RFM22 is TX state,TX_ANT should be = 1, RX_ANT should be = 0
pin 3	RX_ANT:	Rx Antenna select input pin, When RFM2 2 is RX state,RX_ANT should be = 1, TX_ANT should be = 0

For RFM23BPS:

pin 3	TX_ON:	Tx ON select input pin, When RFM23BP is TX state,TX_ON should be = 0, RX_ON should be = 1
pin 4	RX_ON:	Rx ON select input pin, When RFM2 3BPS is RX state,RX_ON should be = 0, TX_ON should be = 1

thanks nicely information
my protocol is control and telemetry so no need these transistor ?

these days I want to change rfm22 module to rfm23 module

[jdl]

Right, you do not need these transistors.

Here are some photos of a modified Oplink Mini (replaced RFM module). May be helpful. Take care not to snap off ANT and GND pads on RFM23BPS module if you solder the coax cable directly to them. They cannot handle almost any mechanical stress coming from twisting or pulling the cable. So it is a good idea to mechanically fix the coax before soldering it to the RFM23BPS.