Incrementally move servo
 

• I am trying to use rc transmitter and receiver to remotely adjust the vent on my bbq smoker as I monitor the temperature from afar.

I have the AX-7s system tx/rec pistol grip. I have the SPT servo model SPT5435LV-180. 6v power converter arrives today.



I need to adjust the vent/servo frequently to open or close the vent on the smoker (2” travel) and have the vent/servo stay as adjusted! I’m using a lawnmower throttle cable from vent to servo!



How can I best accomplish my goal?



Obvious novice seeks advice!!

your going to need a servo Id go with something that has a limited arc as in under 20 degrees of swing... build a housing to hold the servo pick a aluminum arm and connect a micro U bolt to hold lawnmower cable..maybe a lead end so you can dremel a slot to hold u bolt.you can use a high amount servo sweep but will have to make a swing arm to take up the extra amount of throw

In the spirit of DIY, I will avoid the obvious question of - don't they make stuff for this? I get it, you have a cheap radio, and you want to try stuff :)

Most transmitters are spring loaded and each function is designed to return to center when released. The exception would be a throttle channel on a airplane or helicopter radio. My approach to using what you have would be to use the steering wheel, disable the centering spring, and set the servo so that full left steering is vent closed, and full right is vent full open. Before you disable the spring, mark the top of the wheel, so you get a visual representation of the vent position.

Another possible option is to use the trim function, although I suspect you won't get enough throw.

Make sure the vent moves freely by hand in order to minimize load on the servo.

Good luck

Might not provide enough range of movement, but put the servo on the steering channel and use the steering trim button to adjust. A longer servo horn will give you move movement if needed

I believe the 3rd channel on your radio is a flip switch and you would need a variable dial instead, something like this radio system here would let you use the 3rd channel incrementally adjust the air flow:

do what i suggested far more simple and easier

The transmitter is going to need to be powered on any time you want control of the servo on your smoker. If you plan on smoking for several hours you are going to burn through lots of AA batteries. I'd get another power supply/converter of the correct voltage and get rid of the batteries for the transmitter. You might also look into a servo as you could eliminate the need for a transmitter or receiver, and all of the associated complications of getting everything to work together. You could probably mount the servo tester inside and extend the servo lead to connect it to your smoker. A fuze on both ends of the positive wire is probably a good idea if you go this route.

https://cimg8.ibsrv.net/gimg/www.rct...deb6a2c680.jpg

Nice idea, I like the servo tester better for this application, and any wall watt USB style charger should be more than enough to power the servo tester as well so you don't have to worry about any batteries.

I used a wall wart, a relay, some LEDs, a generic replacement car door switch, some cat 5 cable and some receiver connectors to make an indication system of the garage door position inside the house. Red LED illuminates any time the door is in any position other than all the way down. Green light only comes on when the door is all the way down. All to keep my wife from letting the cat out into the garage when the door is open.

https://cimg9.ibsrv.net/gimg/www.rct...d05af91fcf.jpg
https://cimg0.ibsrv.net/gimg/www.rct...2227bdfc12.jpg

Servo Tester
 

If I understand the suggestions on using a servo tester…..I will have servo tester inside my house….run power from house to servo! Operate servo directly!

I currently monitor temperatures from the comfort of my sunroom. The smoker is 20 feet away. Won’t be a problem!

I hope I have this right!

thanks for the input from everyone!

Good advice
 

Thanks to all who posted suggestions! I believe the servo tester wired directly to the servo is my best solution! I had the “wireless” idea in my head and never considered this simple, and easily doable, solution! I’ll post when all is working! Thanks again

Fuse on positive side?
 

About fusing the hot wire….is that to protect the servo in case of overload? What type and size would you suggest?? Wall plug converter puts at various voltages at 1amp max.

Thank you!

Fuse
 

I’ve read that fusing the 33’ of servo extenders That I’m using to reach my smoker should be done! Videos I saw shows the fuse inserted in the ground wire and not the red wire! Which is correct or does it matter?

I have a background in vehicle maintenance so I always ran a fuse on the hot side as nearly everything else is the ground. With the extension I don't think it matters. If you do put the fuse on the ground I'd put it as close to the power supply as possible.

if you get a stepper motor its incremental by default. so then the question is how do you make it move? well i assume you are trying to control temperature. if you get an allen bradley micro810 you can pulse the stepper motor with the outputs. this will get the motor turning. then you get a thermistor to measure temperature and plug it into an analog input. write a few lines of code and you can have automatic temperature control.