INTRODUCING: the "Roto Damper"


 
first of all thanks RalphTrimble for sharing the stl files with me.
it's a great design.
i used a servo from hobby king which is a analog metal gear servo CS-929MG works and fits perfect!

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the parts 3d printed from abs

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parts put together

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side view of the rj45 connector

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used a 32mm stainless steel pipe and hard soldert it to a stainless steel plate which fit the kamado inlet.

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all parts together

won't beable to test it comming weekend so have to wait another week :-(
then start tunig the pid's and start smoking.
will upload a picture when attached to the kamado when i have the first ribs in the :maroonkettle:

regards,

Ruud
 
Nice job, your build looks great!
Thanks for reporting the alternate servo that works, that's good to know. If you don't mind, please report back on the performance and reliability of that servo. I had grown tired of chattery Tower Pro MG90s servos and have been trying out a Hextronics servo instead, but it wasn't a direct fit, I had to make a custom RD3 part to fit. It would be nice to have a quality direct fit alternative...
Also, being in Europe I know you are using a different CAT5 jack than we get here. Can you share the info on the CAT5 jack you used so I know what to tell other folks in Europe to look for?
 
Nice, an original Roto Damper there... been a while since I've seen posting about that one... Glad it's finally coming together for you.
 
Good morning Ralph. What are my purchase options for the RD3? I think I want the hand wired version. I'm not sure what the benefits of the other option are to be honest. I may have access to a printer, so just the files may be fine, but direct purchase is an option too. Let me know, thanks!
 
Hey Ralph - Finally doing my 1st RotoDamper Run - had 2 events tomorrow. A social for 45 people and a wedding rehearsal for 54. Cooking 3 whole briskets and 40lbs of pork butts. Have the butts and one of the briskets on the new RD3 setup and the new 22" WSM. Did the maiden burn in run on it this afternoon and it ran great. Now we're playing for money :)

I didn't realize that the 3rd probe would still work when using the RDTC option?
 
Yes, the RDTC board will feed the pit probe and the first two food probes, the last probe you can still plug directly into the HM and use if you like for food or ambient temp.
 
Ralph - when I wasn't messing with it, the RD3 ran the entire 16 hours within about a 10 degree range on my new WSM '22 - I'm imagining that will tighten up even more after I get the gasket kit installed and the smoker develops a coating on the interior surfaces. With the straight fan setup, it was varying like 20 degrees or more.

Kudos on the design - great job!!!
 
Thanks for the compliments. I am sure you can dial it in better than that as well, gasket help a lot... What % was your HM running through most of the cook? I like to shoot for about 30%...
 
Just sharing a screenshot of what the RD3 is capable of on my smoker. I'm using the HM 4.3 with the RD3 on a FireMagix 24S-SM. You can see that I started out at 225, went to 250, then 325, then down to 275. Pretty impressed. Thanks Ralph!

y4mG5yTRZl2JZJ3N-ybKDZuHbrGBR4i5HaUPGu1QMopuRY61n4kV2RpkVMR38EN0rC4QCoduaWfx0D8FRZ8Ob6jw01RyeKUoYq-TC4Q2bQH6MQiGTWw1qV0O2bkMgs19WUzWQF4_jHSWcExNuYowrlwXfZvXkGbYWC7jRCHr9TxiKjiWV7A_1WiK6xAWcjDUxLwGPnY6mO20MG3PojR_FGwYA
 
Hey Ralph, Just wanted to say thanks for the stl files and the work you've put into this. I've got it all printed out and assembled. I'll probably start a test cook this weekend. I'll also try to take pictures of everything and add them on here, so you can see it.

I do have one question, has anyone had any issues with a jittery servo? It seems like it's getting fantom signals or something from somewhere. When I send the actual open/close it works, but when sitting idle...it has a slight jitter in it.

Thanks again.
 
Glad your print worked out Victor, as for servo jitter, that's a long standing situation with a couple factors....

First factor would be a quality servo, there are a lot of cheap bootleg Tower Pro MG90s servo's out there...

Second factor could be resistance. If your valve is too tight the servo can struggle to move fully into position, make sure the servo is seated all the way (and not hung up on first layer squish from the print, scrape that away of necessary). Also make sure the servo isn't jammed too tighly into the hole, if you have to force it in that will probably bind the gearbox a bit. Loosening the servo screw a bit can sometimes reduce servo binding...

Another factor is HM firmware. Initially the servo was always powered on and would move with the slightest change in HM output. Later firmware was changed to a move and rest type of action where the servo would power down after moving, and the sensitivity has been adjusted so the servo doesnt move until the HM output changes significantly. I think recently Bryan changed the firmware back to having the servo powered on all the time.

I've been back and forth, had jitter, and zero jitter depending on the combination of the above. I had initially not been fond of the move and rest firmware because my MG90s would sometimes twitch and stick open and the HM would put the servo to rest in the open position letting my fire go out of control. Frustrated with this I changed to a Hextronik HXT900 servo which never jittered or twitched a bit, working great for a year (powered on 24/7). Recently I flashed the latest firmware which I think keeps the servo energized and my servo was dead a few days later. Coincidence? Probably... I ordered another HXT900 and am installing it tonight, guess we'll see if it takes another year to kill this one! BTw, the HXT servo doesn't fit the std RD, the shoulder is too shallow, needs a custom part.
 
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VictorPriceJr said:
I do have one question, has anyone had any issues with a jittery servo? It seems like it's getting fantom signals or something from somewhere. When I send the actual open/close it works, but when sitting idle...it has a slight jitter in it.

Thanks again.
Click to expand...

I have found that you can get rid of almost all of the jitter by introducing a capacitor (47uF 10V polarized) across the power supply of the servo (red and black/brown wires). Ralph is correct, there are plenty of counterfeit MG90S servos out there. I buy mine directly from TowerPro and another good source is Adafruit.
 
WBegg said:
I have found that you can get rid of almost all of the jitter by introducing a capacitor (47uF 10V polarized) across the power supply of the servo (red and black/brown wires). Ralph is correct, there are plenty of counterfeit MG90S servos out there. I buy mine directly from TowerPro and another good source is Adafruit.
Click to expand...

This fix sounds like a straightforward way to "even out" the servo action. How did you reach this solution, and can you just stick the legs of that capacitor into the socket of the servo when you plug in the leads (is there enough room)? To be sure the polarity is correct, the + side of the capacitor into RED and the - into black/brown, correct? Does this act as a "buffer" to the signals to help smooth out the action?

I'm researching options before starting construction on my own gravity feed build and will be going with the Heater Meter setup for sure. Looking forward to building it with the Roto Damper as well. I'll have to contact Ralph for those solid files - his RD design looks great!
 
i actually put mine in the recess of the LAN jack, and it fits nicely. There was a thread regarding same issues, and one of the remedies that evolved out of that discussion was adding a capacitor. I believe what it does (someone correct me if I'm wrong) is it prevents a supply voltage drop when a signal is sent to the servo.

And yes, + to red, and - to black/brown.
Something like this ...
WUnTASy.jpg
 
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