I'm confused and a bit frustrated, would appreciate any help as I'm not sure how to proceed.
Setup: I have a pixhawk autopilot running Arduplane 2.77, using Mission Planner 1.2.95
I've been following this guide to get my CHDK enabled camera working with my pixhawk. I'm interested in getting the camera triggering based on distance traveled.
Obviously the guide was written with APM in mind, so it needs to be adapted a bit for pixhawk; specifically the setting for RELAY_PIN. I've kept the rest of the settings the same as in the tutorial.
Pixhawk has 6 AUX ports according to the quick start guide, I am assuming that the numbers above the pins correspond to the AUX port numbering. When you mouse over the RELAY_PIN parameter, it says that pin 54 corresponds to Pixhawk FMU AUX1.
Tried setting RELAY_PIN to 54, no joy. Did a bit more looking, discovered in the release notes for 2.77:
"Improved relay code
The relay and servo set code has had a major overhaul, with up to 4 relays now supported for MAVLink control and much better support for the DO_SET_SERVO, DO_SET_RELAY, DO_REPEAT_SERVO and DO_REPEAT_RELAY MAVLink commands. Along with these changes is a new parameter BRD_PWM_COUNT which allows you to specify how many auxillary PWM outputs to enable, with the remaining outputs being available as digital relays. This allows you to re-assign some of the aux servo outputs on Pixhawk for use as relays, by setting the RELAY_PIN, RELAY_PIN2, RELAY_PIN3 and RELAY_PIN4 parameters. The pin numbers for these pins start at 50 for the first aux servo pin, and go to 55 on Pixhawk."
Additionally,I found this github issue about this same problem that states that the Pixhawk can't trigger CHDK because its relay pins operate at 3.3V instead of 5V.
So i suppose my specific questions are:
1) Is AUX1 pin 50 or 54?
2) Can anyone confirm that the relays, when working properly, won't be able to trigger CHDK?
Replies
Tks Phill Simpson! I will build Reuben's circuit to my CHDK. My step-up 3.3-5v goes to the drawer :( haha.
Greetings to all,
Congratulations for the beautiful work of the group, I hope to contribute.
I got this step-up 3.3-5V. Can I use it in my circuit for cable CHDK USB + pixhawk? I need add 5V central aux line?
http://produto.mercadolivre.com.br/MLB-621739265-conversor-dcdc-ste...
I want to build a simple circuit like Reuben CHDK circuit.
Best Regards,
conversor-dcdc-step-up-de-3v-para-5v-su-06-22399-MLB20229346077_012...
Plinio,
No, you can not. See previous posts on these converters. You need to use Marco's or Reuben's circuit.
I've been following this thread with interest. I have used infrared triggers for nikon cameras on both APM and pixhawk without problem, but now have to do the CHDK thing with canon cameras that don't have inrfared triggers. I have bought the bits to assemble a number of the suggestions here and have started to tinker. However, I just realised that I am plugging an ESC into the pixhawk output which means that I have 5V on the rail. Theoretically, I should just be able to use the relay output and all should be good. I would assume that most people would be using an ESC with a BEC on the pixhawk output that would take the rail to 5V.....so why is everyone having an issue?
ausdroid,
The issue is the voltage on the output of the signal pin of the Pixhawk, not the positive rail. The signal pin voltage is 3.3 volts, not enough to trigger the Canon via the USB port. Marco's circuit increases that voltage to 5v. My understanding is that you should not need the circuit for an APM but I don't have one so I can't verify it.
In addition, many of us use ESCs that don't have a built-in 5v BEC or, as in my case, don't trust them. In that case a separate BEC is needed to supply the 5v.
Many of us have tried that approach without any success. Please report back your results if by some miracle you get it to work :-) Reuben's circuit works and it is fairly easy to build, so I think that is what most people are doing. If you lack soldering skills, you might be able to talk someone here into building one for you.
Gary
I think I just had my light bulb moment.... Regardless of the voltage you put on the output Vcc rail, the signal voltage will only ever be 3.3 Volts. Is this correct? If so, you actually need two things;
1) You need 5 volts on the Vcc rail to feed to the USB connection
2) You need to use the 3.3 V signal to switch the 5V.
Can someone tell me that I have finally worked this out?
Eureka !!
Yes, it was like a blinding light going on inside my head! I couldn't understand the problem with the whole 5V thing. I assumed that hitting the rail with 5V meant that the PWM signal also went between 0 and 5V......noooooo! I think that has been confusing everybody. Where you get the 5V from is irrelevant. The trick is switching with 3.3. This now becomes a trivial task.
While I have no doubt that Rueben's circuit will work nicely. I think this should do the job;;
http://www.digikey.com.au/product-detail/en/DO061B/CC1061-ND/139580
Hang on....does anyone know the "off" voltage for the AUX pins?
-
26
-
27
-
28
-
29
-
30
of 45 Next