Author Topic: Beta-DMX Servo Controller Project (See first post for specs and features)  (Read 37028 times)

Offline packetbob

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Re: DMX Servo Controller Project
« Reply #90 on: October 11, 2011, »
I'll take one or two boards if there are any left.....

Offline dlhoppe

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Re: DMX Servo Controller Project
« Reply #91 on: October 11, 2011, »
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I have a couple of boards coming, where can I find the Mouser BOM?


I posted the BOM link and the firmware on the first post of this thread.

Offline egenoup

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Re: DMX Servo Controller Project
« Reply #92 on: October 11, 2011, »
I have two (2) extra boards up for grabs... Dave do you have a list of who should get these boards?

Offline dlhoppe

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Re: DMX Servo Controller Project
« Reply #93 on: October 11, 2011, »
Charles, whoever PMs you first gets them. Mike is doing the same.



Offline dlhoppe

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Re: DMX Servo Controller Project
« Reply #94 on: October 11, 2011, »
We should have a good variety of beta testers. Thanks everyone for stepping up. We're counting on you.

Please post about your build experience.


Dave

Offline holland lights

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    • holland lights
Re: DMX Servo Controller Project
« Reply #95 on: October 11, 2011, »
Well i sent money ton1ist ,and  sent my address to egenoup (did he mean he wanted payment, not just my address in the email?).

Offline dlhoppe

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Re: DMX Servo Controller Project
« Reply #96 on: October 11, 2011, »
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Well i sent money ton1ist ,and  sent my address to egenoup (did he mean he wanted payment, not just my address in the email?).


Please work out arrangements via PMs.


Thanks

Offline dlhoppe

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Re: DMX Servo Controller Project
« Reply #97 on: October 11, 2011, »
I added some additional items to the first post of this thread. Firmware, configuration tool, as well as some instructions and notes regarding features and recommendations.

I'm hoping Mike will send me some more detail on the build options (split vs single power supply, DMX out, etc). Once I have that, I will update the doc on the first post of this thread.


Cheers,
Dave

Offline dlhoppe

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Re: DMX Servo Controller Project
« Reply #98 on: October 11, 2011, »
All PCBs I'm providing will be in the mail tomorrow.

Offline dlhoppe

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Re: DMX Servo Controller Project (See first post for info)
« Reply #99 on: October 12, 2011, »
For you beta testers, I made a couple of small changes to the BOM. I removed an unnecessary item (the 3A diode) and added the 16P socket for the LED driver. So for those who already placed their order, you're missing the 16P socket and will have an extra part.

Sorry about that.
« Last Edit: October 13, 2011, by dlhoppe »

Offline dlhoppe

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Re: DMX Servo Controller Project (See first post for info)
« Reply #100 on: October 12, 2011, »
Thought I would post this pic of my latest build (using up my breadboard parts). I'm missing a few things, but it's mostly done. I've added some annotation to show the options.

Power Supply:
For single power supply (same supply feeds logic and servos), place diode at D4 and leave D1 open. Connect power to "S" in P1 block only.
For dual power supply (separate supplies for logic and servos), place diode at D1 and leave D4 open. Connect logic power to "L" in P1 block. Connect servo power to "S" in P1 block.

DMX Pass-through vs. Re-broadcast:
For pass-through, jump the two spots shown circled on the photo. Leave the second line driver chip out. (C10 is also not required with pass-through)
For re-broadcast, do not jump. Instead install the second line driver chip and C10.

Power monitoring:
U8/C2 are there to allow for monitoring the servo power bus. However U8 is not included in the BOM. U7/C1 are there to allow for monitoring the logic power bus. Only one of the buses can be monitored. We felt it a better idea to have the PIC monitor it's own power supply to prevent brown-outs causing cycling/rebooting. However it's the builder's choice to determine which bus they want to monitor. In either case, if the power drops below the trigger point (3.075v for U7, and 4.375v for U8) the PIC will go into fail-safe mode (shuts down servo and LED operation) and flashes the red LED. Cycling the power will clear it.


Dave
« Last Edit: October 13, 2011, by dlhoppe »

Offline dlhoppe

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For those of you that are going to add the Ex/Rx for wireless connectivity. I've been testing mine with a "stock" Ex/Rx and it's been working fine. However I do have a little concern that we're only feeding it 3.3v. There's no headroom there for any dips in voltage on the logic power bus. Please pay particular attention to the wireless performance. The worst that would happen is we'd jump out the regulator on the Ex/Rx. But I'd like to save that as a last resort to try and keep the Ex/Rx "stock".


Dave

Offline dlhoppe

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OK, just to make sure everyone is clear on the status of this project. We are involving some volunteers for beta testing. This is not a coop. As soon as we're done with our testing phase, then we'll approach the coop managers to get this thing officially released. Please check back for updates. We should start seeing feedback from the testers before too long.

Thanks for your patience,
Dave

Offline dlhoppe

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I should mentioned recommended power supplies since I don't think it's come up much in this thread. After a fair bit of testing, I have come up with the following recommendations.

If you're going to use the split power supply (separate supplies for logic and servos), consider this for the logic power bus:
   
Power consumption for wired only (no Ex/Rx): 30mA
Power consumption for wireless (with Ex/Rx): 120mA

So I would recommend a 6VDC supply with at least 200mA output for the logic side. That should give some headroom and prevent running something at max capacity. I can't imagine you would save much if you planned on wired only and bought a tiny supply. You'd end up under-powered down the road if you want to add an Ex/Rx later.

The same unit RJ specifies for the Tx would be a cost-effective choice: You are not allowed to view links. Register or Login


For the servo power bus (also applies to single power input configuration), it depends on what your plans are for servo size and load. In my testing I've found that borderline power supply was really affected by the starts and stops of servo movement, which causes glitching in all the servos. I'm using a bench-top 3A power supply and I'm able to dial down the current to simulate less capable power supplies. I would stick with 6VDC and a minimum of 2A. If you're going to run high-power digitals and/or large scale servos, then you'll want to bump up the output current. Unfortunately, servo manufacturers do not specify current consumption with various load conditions. Some will show stall current, but that's rare. In my tests, I had 8 servos in constant motion and was pulling around 1.5 amps, but the servos weren't connected to anything to load them down. I stalled one of the digitals and the current draw spiked to 3A or more before the fuse opened. So shoot higher if it's within your budget. I did a quick search and here's a possibility at 3A output giving some headroom to grow into: You are not allowed to view links. Register or Login 

It goes without saying that using the single power supply configuration would be simpler. However, some may have issues with noisy power supplies or such. In that case it's an easy mod to split the power input and power the two buses separately.


Dave
« Last Edit: October 14, 2011, by dlhoppe »

Offline dlhoppe

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A little searching can find other less costly power supply options. For example: You are not allowed to view links. Register or Login