Nice work And yes a lot of info here.... but I'm sure you can turn off whatever you don't want
Do you plan to have your work open source or ..... ?
I'd love to see your code and how you wired this all up. I'm assuming you started with this hardware http://store.diydrones.com/Ardupilot...-apmminosd.htm
Again, nice work
Here's my take on the OSD hardware:
* All connectors, except GPS are DF13, 1.25mm pitch low profile connectors. These are what 3DRobotics use on the APM boards, I chose them because they sell all the different pin counts in various lengths. This saves people having to crimp them!
* GPS is JST SH series, also APM compatible (we have several APMs here, so very nice to have easy compatibility and use of existing cabling).
* Added I2C port
* Added two Analogue ports ("airspeed" and "temperature"). Should allow the use of an analogue differential pressure sensor or 3DR's airspeed sensor.
* Added current port - again, compatible with 3DR's current sensor. VDiv on input supports up to 10S.
* Added second voltage divider for upto 6S. The LDO I have onboard only supports up to 6S voltages so I need a second port for aus power for 8S or 10S aircraft.
* Added 3 pin header for voltage section. If not using the 2 pin power connector, a jumper can be mounted to connect the current sensors voltage reference to the power system. 3rd pin acts as a safe place to store the jumper (pin 1-2 does nothing, pin 2-3 connects vref to vin.)
* Added EEPROM for settings storage (footprint supports up to 512k) and possibly basic datalogging. EEPROM is too slow for complex datalogging IMO.
* Added a heap of power filtering.
* Isolated 5VA/5VP/5V for the Max7456 to supply cleaner video.
* 75 Ohm impedance routes for video.
* Testpin/pogopin programming pads.
* Protection resistors on most inputs.
* Added BMP085 onboard. Not the pressure sensor of choice for me, but it seems popular in the open source world. *shrug*
Camera/Transmitter connectors are 5 pins. This allows video, audio pass-through, filtered input voltage, ground and a second passthrough that could be used as a second audio line, or for a regulated voltage. On an aircraft i built just last week I had a crazy bit of wiring to get 8v to both the TX/RX off a 12S battery and still get the OSD in the loop. Not very neat. These connectors would have been so handy.
* Check that the BMP085's I2C lines are 5V tolerant.
* VDiv for current sensor to 12S.
* Isolate GPS power pin.
* Add PCB heatsink for 5V. Would only be worth added if the boards are machine assembled or at least stencilled.
The LDO is SOT-223 which is pretty huge, but I would be applying upto 6S to this so I need it's ability to survive dumping that much waste heat. Couldnt be bothered designing a SMPS for this board.
The board has some vast areas of copper with no components or routes on it. The board is fairly well laid out for RF performance (rotating the MCU CW 90* might help a little but could make some other things a pain). Seeing as the board is still fairly small (45.5x31mm) I'm not too bothered. The bare copper is used as heatsinking for the 5V PSU and MAX7456.
Discretes are mostly 0402, but are not very densely packed, so they should be easy to hand solder for anyone with experience.
There are no thermals. I don't like the ringing that the high inductance of thermals creates They also serious limit the ability for heat to escape.
We don't use silkscreen for designators here.. Designators moved to a mechanical layer for assembly diagrams.
Great to see you got something out of the schematic, even though it wasn't exactly done .
I can see that you have mounted decoupling-caps on MAX7456. As far as I can see, MAX7456 have internal load-capacitors for the crystal. I also had them mounted on the first versions, but it works just fine without.
The 5-volt regulator is not a bad idea, but I think it will get quite hot with 6S li-po.
I tested a version with 5-volt regulator, but decided not to go with that solution, as it got too hot for my taste.
- It's one of the first versions:
But in general it looks very good .
The extra EEPROM is a nice feature. I have a few different I2C EEPROMS laying around for testing, but been busy with other things lately.
Very Cool !!!
Looks like you are becoming an expert and at soldering MAX
- got modified quad running - should be doing more flying/testing soon !!
Dennis, what does this mean from the ImmersionRC Beta version ..
“For example, a 4 channel RX can now emit 12 channels of PPM on CH1 in Multicopter mode”
I don't understand all I know about this ..
Currently, in flying the quad, channel 1,2,3,and 4 are set aside for controls -
channel 5 is for control mode selection (NAZA)
channel 7 and 8 for RSSI and LINK and 6 for PPM
I'd like another channel for a servo to tilt the camera.
Does this mean it may be possible ?
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