My dog needs your help

Thread Starter

rescuepilot

Joined Dec 10, 2023
8
I’m new to the forum, please forgive me for the newbie questions.

I train Labrador Retrievers. Part of this training requires me to raise and lower a white flag; usually this is done with an assistant. I’m trying to develop a device that I can do this flag raising/lowering remotely. FULL DISCLAIMER: I have very limited electrical experience

Needs:
  • Remotely trigger 12 VDC motor that rotates lead screw until it is stopped by a limit switch. Remotely trigger again and the 12 VDC motor reverses lead screw until it is stopped again by limit switch.
  • Similar to this setup in this video. But done remotely instead of a DPDT switch.

Concept:
  • My plan is to use a lead screw mechanism to tilt an arm both vertically and horizontally (see attached pic)
  • The lead screw will be driven by a 12 VDC motor (still looking for the right motor).
  • The motor will turn the screw (e.g., clockwise, flag lowers) until it hits a limit switch and stops movement.
  • Remotely trigger again and the motor turns the lead screw the opposite direction (e.g., counter clockwise, flag raises) until it hits a limit switch and stops movement.
  • The remote trigger is a Dogtra (RR deluxe) that provides a 6V momentary signal via 3.5mm mono jack

Components:
  • Aluminum/Stainless Steel lead screw
  • 12V DC motor (high torque)
  • H Bridge Controller (L298N)
  • 20V to 12V step down converter for Dewalt Battery
  • Two waterproof limit switches
  • Dogtra RR deluxe release

Questions:
  • Do I need an arduino controller to control the H bridge controller?
  • What components am I missing to make this work?

Thanks in advance,
Eric
 

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Thread Starter

rescuepilot

Joined Dec 10, 2023
8

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boostbuck

Joined Oct 5, 2017
510
Unless you are familiar with (successfully) programming an Arduino for such tasks, I would recommend the relay control (post #5) as easier to implement. For such a simple task (a limit controlled reversing h-bridge) it's a great deal less complicated and much more robust.
 

Thread Starter

rescuepilot

Joined Dec 10, 2023
8
Unless you are familiar with (successfully) programming an Arduino for such tasks, I would recommend the relay control (post #5) as easier to implement. For such a simple task (a limit controlled reversing h-bridge) it's a great deal less complicated and much more robust.
Is the relay control a device I can purchase or the wiring schematic from Post #4 in this thread? And how would I interface with the relay control remotely?
 

boostbuck

Joined Oct 5, 2017
510
Personally I would make such a device, but they can be purchased these days for little. For example (illustration only - I haven't vetted the suitability of this particular device):

https://www.ebay.com.au/itm/304892752999

For interface to your 5V pulsed signal, you would need to have some form of signal conversion to match the control circuit. Again, the simplest and most robust, for example in the case of the relay control in #5, would be to operate a 5V relay and use it's contacts to parallel the push-button.
 

Thread Starter

rescuepilot

Joined Dec 10, 2023
8
Personally I would make such a device, but they can be purchased these days for little. For example (illustration only - I haven't vetted the suitability of this particular device):

https://www.ebay.com.au/itm/304892752999

For interface to your 5V pulsed signal, you would need to have some form of signal conversion to match the control circuit. Again, the simplest and most robust, for example in the case of the relay control in #5, would be to operate a 5V relay and use it's contacts to parallel the push-button.
Thanks for the info. I plan on using the 12V motor control relay and schematics in pic 1 but I’m still a little confused on how to electronically trigger in lieu of a push button switch. Boostbuck or anybody else, what’s an example of the “relay control in #5” you would use to mirror a push button?

I really do appreciate everyone’s support on the topic.
 

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boostbuck

Joined Oct 5, 2017
510
The relay is connected approximately as below, where the contacts replace the push button. This assumes the output from your remote control provides enough current and sufficient pulse width to drive a relay. Possibly not!

1704751081369.png

If your source can drive the relay, then this will provide the simplest interface to any device that will accept a push button.

For the specific controller you show, it appears to use opto-isolated switch inputs to ground, so for that I would use something like the circuit below, which inverts a positive-going pulse and connects to ground, mimicking the switch:

1704751328878.png
 

MisterBill2

Joined Jan 23, 2018
18,464
The entire scheme can be implemented with a few relays and limit switches. No processor involvement required. In fact, it could probably be done without the leadscrew mechanism, either, depending on the weight of the flag and the length of the pole it is to be on. I am guessing that the whole thing will be battery powered and thus minimum power draw will be a requirement.
I have a concept that will require a bit of mechanical fabrication to operate switches at each end of the move, and operate another switch in opposite directions at each end of the move. The only electronic part will be what is required to operate a relay from the output of the receiver.
 

Thread Starter

rescuepilot

Joined Dec 10, 2023
8
The entire scheme can be implemented with a few relays and limit switches. No processor involvement required. In fact, it could probably be done without the leadscrew mechanism, either, depending on the weight of the flag and the length of the pole it is to be on. I am guessing that the whole thing will be battery powered and thus minimum power draw will be a requirement.
I have a concept that will require a bit of mechanical fabrication to operate switches at each end of the move, and operate another switch in opposite directions at each end of the move. The only electronic part will be what is required to operate a relay from the output of the receiver.
I just purchased a new AC TIG machine. I figured it would come in handy for some metal fabrication projects like this. The whole dog training device has to be carried into the field and setup….so I’m trying to minimize as much weight as possible. The flag is made out of outdoor sign material, so it is fairly lightweight. I plan on powering the setup with a 20V Dewalt battery connected to a 12V step down adapter. I would be interested in looking at your concept. I’ll probably fabricate a couple versions using boostbuck’s recommendations and your idea. Can you direct message or email me your thoughts? Thanks Eric
 

boostbuck

Joined Oct 5, 2017
510
If we are into simplifying the design....

I had thought a simple pivoted pole, operated by a solenoid with an over-center spring to prove a bit of hysteresis and limit microswitches to reverse the operating pulse. Then a single pulse could operate it alternately both up and down.

It depends on the scale - ie the size of the flag to be operated.
 

MisterBill2

Joined Jan 23, 2018
18,464
The simplest design will be a gearmotor driving a crank that in one position pushes the flag staff to vertical and in the opposite position brings it down to horizontal. Then a single limit switch driven by a cam on the same shaft as the crank. The switch will open in both the full up position and in the full down position. The relay operated by the remote control thing will momentarily allow the motor long enough to let the limit switch close, at which time it can release, and the cam and lever will keep rotating until the other position is obtained. No electronics, only one relay, no switch, and much less hardware, Not quite an original idea but certainly a simple scheme.
 

Thread Starter

rescuepilot

Joined Dec 10, 2023
8
These are the pictures of the white flag. It’s supposed to resemble a person in a white jacket (60” tall). My original plan was to remotely trigger the setup which would tilt the entire flag (simulated human torso) backwards almost parallel to the ground using the lead screw. From the dog’s perspective 200 yards away, it would make it disappear from view. If I wanted it to reappear, I would trigger the setup and the lead screw would drive the flag vertical.
 

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MisterBill2

Joined Jan 23, 2018
18,464
OK, a bigger flag load than I had imagined. Or the motor gets a bit more powerful. But the benefit of not needing any electronics,, no reversing circuit, and very little precision mechanical stuff, is quite significant. So maybe the gearbox is a bit stronger, one foot-pound out=2 pounds force with a six inch crank. That might work when there is no wind. So the concept is worth some thought, at least.

If they were training golden retrievers they could teach the dogs to do first aid as well.
 

Thread Starter

rescuepilot

Joined Dec 10, 2023
8
You train Labradors to retrieve people??????
Ha! No, in field trial competitions the folks throwing bumpers wear white jackets. I’m developing this system so I can train alone when others in the training group aren’t available. The orange bumpers (see pic 3 in previous post) are remotely launched via the controller that emits the 6v signal. The momentary impulse is enough to rotate a servo to trigger the bumper launcher.
 

MisterBill2

Joined Jan 23, 2018
18,464
OK, the gear motor could be an automotive wiper motor, that is strong enough and it already has the crank. Not a whole lot of mechanical stuff needed, OR a power window motor that may be the very best choice, Lots of torque and a better physical arrangement.
 
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