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wakewatcher

Mid Life Crisis

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Probably more complicated than that.

Adding a pot or some other user adjustable input is not a problem. The software to do something with the pot value is a serious challenge. Especially since the PanCam interface operates in an open-loop fashion (there is no way for the servo to tell PanCam about its position).

If I use 2:1 gearing is it possible to move the servo very slowly?

I don't use any gearing and I can get the servo to crawl. Have you tried it on a standard servo? If that is acceptable, then 2:1 will be 1/2 the speed.

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BTW, the new V2.0 has a gentle auto-center feature. It was an issue brought up earlier in this discussion.

After about a year off I got around to working on this again. (Have spent a lot of my free time working on the video processing software.) Anyway I downloaded your latest version 2.1 and burned a couple of 12C508As. It seems to work at low stick deflections but at quick full deflections (and then back to center) the servo goes hard over and doesn't stop until it maxes out. On similiar stick movements on the old version it doesn't behave this way.

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I'm not able to duplicate the problem on V2.1. You mentioned you are using a PIC12C508. You need to use the 12C509 series which has larger code space. The V2.1 program is too big for the 12C508, so some valuable code will be missing.

If you are using a 509 then I will need more hints on how to duplicate the issue. I can fix the code once I see the failure. I will say that many folks are using the V2.1 and they have not run into any problems.

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I burned a 509A and it works better than the undersized 508A however it still is quirky. When I move the stick slowly at some point the servo starts moving and then stops without releasing the stick. To make sure it wasn't just twitchy fingers I used my digital trims to repro the symptom. This is what I'm doing. (Using a Futaba 8U Super) Centering the sticks and trims. Turn everything on. Click trim one click, wait a few seconds and click again. As soon as the servo starts moving I stop clicking the trim. The servo should continue moving until I reverse click trim (or move stick in opposite direction) but it doesn't the servo just stops. I've tried multiple servos and mutliple receiver batteries all with the same result.

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You will just have to click the trim a bit more to keep it going. But instead of using the trim, I recommend using the stick. If necessary, you can dial in some ATV or Expo on the Tx.

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I guess I'm confused. Based on the description of how it works shouldn't it keep going once it starts until the stick is released? (As mentioned this happens with both the trims and the stick. I just used the trims to make sure it wasn't me subconsiously removing pressure from the stick.) Sometimes I need to move very slowly but continuous and fluid. If it starts then stops then I have to move the stick some more it causes a jerk in the video. I'm just not understanding why it stops moving once its started and the pulse width from the transmitter hasn't changed. Thx.

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I'm not sure. How many microseconds are added to your servo pulse when you click the trim one time?

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I don't know but it isn't just with the trim. I'm just saying when I move the stick so it just starts to creep it then stops after starting to move. Since the pulse width hasn't changed shouldn't the pancam continue to 'widen' the pulse until the stick is released? I thought was perhaps a low battery or some friction thing with the servo but it happens with all the combinations I've tried. Have you tried it?

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Yes, I can make it do it, but it is very hard for me to replicate. The cause could be that the incoming servo pulses are not as stable as expected. Or it could be subtle variations in power supply voltages are affecting the PIC's oscillator. Or a combination of that sort of thing.

There isn't anything in the PanCam code that is causing it. However, there are software tricks I could try to see if I can mask the problem. I am up to my eyeballs in accommodating other requests, so it there will be a delay before I can try some software magic. Offering free R/C projects is a full time job in itself.

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Gotcha and totally understand. Just for fun I'm going to try with a different transmitter (or two.) In the mean time I'll go with plan 'b' of taking the spring returns off my joy stick. Thx.

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The new hex file is attached.

I've done my best to optimize the PanCam code for use with digital sub trims. I don't have a clue if the resulting code will help you, but it is the best I can do after five hours of work.

The intent of the original design is to use center return sticks rather than the subtrims. This new code is still compatible with sticks, so that has not changed. I won't post this new code on the project page until I receive favorable feedback on it.

pancam2_2.zip

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I got home early and couldn't wait to try but I must have messed something up. I burned a new 509A pic. However when I power it up the servo starts moving regardless of where the stick is. It moves about 5 degrees (or so) stops for a second and then moves again and repeats this until it hits the end of its travel where it keeps trying to move. I've only got two pics left on hand so before I burn another one thought I'd ask if anything else changed. Thx.

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In case the zipped file was corrupted, I downloaded it and burnt a chip. It worked fine for me. So, I don't have any idea what is going on. You can use a PIC12F509 (they are erasable) or a PIC12C509/A (one time use).

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I burned a new pic and it works. (I guess.) This is what happens on power up it centers then about a second later it moves several degrees and stops. (I can then move it back to center with stick movement and get it to stay.) The dead band (amount of ignored stick movement) seems to be larger than version 2.1 and also seems to change size during use. I used both my Futaba with 'digital' trims and a hitec with standard trims. Same result. Also when I creep the stick/trim to get it moving its slowest speed is faster than I expected. (I can move it slower in by-pass mode.) You've spent a lot of time on this for me and I appreciate it. Perhaps it works great for everyone else so I'm not asking you to tweak it more. My application is for a stationary platform not on an airframe. I think on a moving airframe a lot is masked by the movement of the aircraft.

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I'm not sure why it is acting that way. It works well for me. I've tried JR and Futaba equipment, as well as a couple different servo simulators. I even slowed down the slow speed in this release (any slower and the servo step size is quite noticeable). Further tweaks are probably not going to solve this for you, so I'll leave it alone.

I have thought about creating a new version on a 14-bit PIC, which will allow for extreme precision (I've pushed the 12-bit PIC to its limits). However, if/when I do that, it doubt it will be a published DiY project. If I go to that extreme, it would be a commercialized release instead.

Long story short, I've given this more attention than I expected. To bad it did not help you out.

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