Blackmagic Forum

A very quick test of an app to control Black magic micro cinema camera using the expansion port. I'd been working on a dirt cheap wireless follow focus using an arduino and bluetooth when I heard about using the camera's expansion port. Original app was to allow controlling focus while a camera was on a ronin m gimbal.(I'm still working on that, it uses a servo to drive focus directly)
I borrowed a camera, lens and bm video assist from a friend.
I quickly made another app to control camera. I messed up soldering the D sub and melted 2 of the pins so I could only connect 2 out of the 4 pwm channels. That's why there is a break when I switch wires on the arduino - also had to power cycle the camera to make it change properly - that is purely because of my terrible construction skills, if I had all the wires correctly connected I think it shouldn't be necessary.
Interface is a bit clunky so sometimes button presses etc don't register(probably made the buttons too small).
Power to camera is coming from the mains power of the camera via the d sub(which is also powering the arduino).
The 2nd bit I'm changing the white balance which is a bit hard to see in the video but it does change it.
Video is terrible quality, as it was shot using an ipad(only other camera I had available)
Lens is olympus 12-40mm.
Cost of parts around £30.
Since posting I've tried with 2 more lenses, a cheap olympus 17mm and canon 16-35 via active speedbooster, both work fine. Though the canon has more stop increments than the 12-40 so the numbers seen in the app don't exactly match, ie 12-40 goes 2.8 - 3.2 - 3.5 whereas canon goes 2 - 2.2 - 2.4 etc so I'd need to map the lens stops differently. I'll probably add the lens mapping ability and lens details storage to the app - so you just choose which lens and it displays the correct stops(and you don't see it in the video but you can mark distances as well)

Dmitry Shijan wrote:RMILEC PWM to SBus Signal Converter arrived today and i test it. Unfortunately it acts same as smaller model i tested earlier. Works very well with Servo controllers but don't works with simple on/off buttons. Probably we need to find some kind of special PWM buttons which generate some kind of signal to work with those PWM to S.Bus converters. Any suggestions?

IMG_4605.jpg

Stu Aitken wrote:both pwm and sbus require a very specific sequence of signals to generate a 'button press' either up or down
you have to send a tightly defined 'mid' then a low or high value in direct succession to trigger - this is easy if you use an arduino and know what values are accepted but I have

Dmitry Shijan wrote:

Stu Aitken wrote:both pwm and sbus require a very specific sequence of signals to generate a 'button press' either up or down
you have to send a tightly defined 'mid' then a low or high value in direct succession to trigger - this is easy if you use an arduino and know what values are accepted but I have

I find one more interesting thing - if i connect PWM servo controller to that board, map it for example to ISO, and turn veeeery slow i can find a small placement position in the middle of rotation when it switches ISO from 400 to 800. When i turn it back it switches ISO back from 800 to 400. This is very good sign! It can work! It can switch things back and forward! But we need to find some kind of dedicated PWM button switch for this board or replace potentiometer in servo controller with two fixed resistors and two buttons to switch settings front and backward.

P.S. Done some measurements. It switches in average range 1.9 to 2.7 kΩ

binarymob wrote:Hey Guys. I'm a super newbie so forgive me if this is very obvious.

I'd like a simple LANC start/stop.
Is it possible to make this with a normal stereo jack and a switch?
I stripped an audio jack and tried to attach them to a button, but got no response from the camera.

Is there something I'm doing wrong?



Thanks for the assist.

Integrated control Canon Sony Panasonic BMD ZCAM camera.
Built-in Bluetooth and WiFi module.
Built-in LANC distributor, use together with BM5.
0.9-inch OLED screen supports function selection.
3 custom band switches, 1 scroll wheel, 1 recording switch, 1 joystick.
Slot for 2 pcs 18650 battery.
Supports to control Tilta Necleus N/M motor.
Power to the dummy battery.
usb upgrade firmware
(freely giveaway the upgrade firmware for the controlled kinds of camera)

Howard Roll wrote:The G2 has no provision for Lanc, nor BT unfortunately.

Good Luck

Howard Roll wrote:The Rest API is fairly well documented, wouldn’t require any reverse engineering or wireshark voodoo. The controller would just need to send simple http commands. Like most things in this world, it’s possible, and doable, but somebody needs to feel it’s worth their time to implement.

Good Luck