Implementing An Idea

Question

Dear all, I am new to robotics but I have an idea that Iw ould like to create as a demo.

I would like to make a nice demo and put a robot in the inner part of a door so I can remotely control it to push the handle of the door to open it.

Can you possibly assist me by telling me which components I would need to be able to reach this demo ?

Many thanks in advance !

Hakem,

thetechguru · Accepted Answer

Depends on the door handle. You might be able to use a servo, or you might need a motor and H-bridge depending on how much torque is required to pull the handle. (you could also use a pulley system to get a mechanical advantage with a lower power device like a servo). Not to drive sales away from EZ-B, but a single function like this is probably less expensive to do with a Raspberry Pi or even an Arduino depending on what you want to use to trigger the door to open. Alan

hakemrb · Answer

Hello Tech Tech Guru, Thank you very much for quick response. It is true that a single motor can do this single function. I wanted to do some "show off ! " hence the idea of a robot. What I imagined in that a robot arm base is stuck to the lower part of the door. 1-) The arm makes a movement to reach the handle; 2-) Then gripper to touch the handle; 3-) then a gesture of 60 degrees to move it down 4-) Then make a sound: you can now push the door to the person who's outside; Instead of playing around with servos and have cables all over. I thought to use some ready to use arm that can store the gesture and use it .

hakemrb · Answer

As for trigger, remotely either z-wave or wifi or anything that can allow easy control ! Thanks

thetechguru · Answer

The reason I ask about trigger is that the EZ-B needs to be connected (via WiFi) to a PC or smartphone at all times to operate. Getting a signal to it that the door needs opening could either be done through a sensor on the EZ-B or something that the PC could detect (like proximity of a Bluetooth device). A long enough robot arm could give you the mechanical advantage needed to just use a servo as the control. You will probably need to experiment some. Do you already have an EZ-B?

hakemrb · Answer

Hello Guru ! I don't have a EZ-B as yet as I am just starting working on the idea . This is for my guest house whereby when I am not here, I wanted to get them have door opened spectacularly. I will put keypad outside and find a way to send signal . Does the EZ-B integrate with any arm or is it part of the existing set ? Thank you so much fo ryour lights

thetechguru · Answer

EZ-B integrates via digital ports. If hte arm is servo based, you can plug in directly. If it has motors, you may need H-bridges. Alan

ptp · Answer

you need to know your hardware options, let's start with EZ-B the only known part so far: There's more than one way to skin a cat, sorry cat lovers you can control analog servos, digital servos (Dynamixel), you can use UART to communicate with an external controller or you can use I2C. i see a few options: 1) open/push the door handicap door opener https://www.aliexpress.com/item/Handycap-openers-for-doors/2034195952.html the solution is a motor, controller and remote. You can hack it: 1.1) using the motor 1.2) via controller if there are visible digital pins 1.3) via infrared (remote controller). buying a kit like that, gives you some relief,you don't need to build mechanical extra parts, you can exchange some tips with the manufacturer about you port weight, open directions, and other stuff. 2) electric lock you will need a electric door strike https://www.amazon.com/Electric-Mechanism-Security-Intercom-Systems/dp/B00164SFFQ and you will need to adapt to the existent door, there are some combinations allowing manual (handle) and automatic (electric). with some work/luck you can power both devices with a single source 12V. if you decide to interface directly to the motors (door and strike) the cheapest and easy solution is to use a darlington transistor like a TIP 120 or similar, there some adjustments but you can have an idea from here: https://bildr.org/2011/03/high-power-control-with-arduino-and-tip120/ you can use a H-bridge (Alan response) but is not need unless you want the motor to rotate different directions. The speed can be controlled via PWM. This is the easiest implementation and probably the cheapest more or less $500-$600 if you add the EZ-B. If you want the wow effect via an Arm Robot, prepare to spend some money on heavy/powerful digital servos plus some heavy robot base to push the door. I can extrapolate more, but if you are serious to build something like that is better to define a budget.

hakemrb · Answer

Tiago, Thank you for all thorough links, I went through all o fthem. It is great to see such reactive forum with passionate ... Let me tell you more about my idae and where it came from. Basically, I run this guest house where guests arrive anytime, it can be midnight and I thought I would need a Door Access Control system, with temporary codes for each of the guests. As I looked at the prices of descent system , I realised maybe for the same budget ( less than 2000 USD), I can do something more spectacular using robot or something out of the box . Which is not necessary an electronic classical door lock. So here is what i thought, a few ideas ( maybe I'm too much of a dreamer :-) ) : 1-) Get some nice design robot like the Ez-Robot or other ( which impresses with its look) and let it come out of a window , which is on top of the door. It will hold an envelop with key code for instance or a key that it can throw to guests, who will be totally surprised to see a robot coming out unexpectedly from the top of this old looking house door ! 2-) Other possibility is to put a Robot Arm on the back of the door around a classical handle. It would do a gesture to open the door by playing with the door handle and give some speach like welcome with name of guests. This is triggered after the guest has said he arrives and I send command via wifi or z-wave or any other mean; 3-) Even more crazy , but less realistic, get a robot come down from a rope from top of the door with keys in its gripper to handle them to guests ; 4-) Any other that follows same spirit ! A fun, spectacular stuff for this budget that does the job of handing the keys or opening the door to the guests So, budget is 2000 USD max for something worth. Allow me to dream as I don' tknow much about technicallities of robotics today. I just want to take some almost ready to use components and put them together to come to this result !

CardboardHacker · Answer

I think the handing the envelop option would be best for this application security wise, as the door would probably be to heavy and the arm you are looking at would only be 5-7inches long, barely enough to get the door open.

hakemrb · Answer

Hi all, Based on your feedback, I have continued and done some reading in the forum + youtube, ...etc. I come down to an easy question I could not figure out yet. How, in practice, can I trigger a saved routine via Internet ( Wifi) to the Ez-Robot. I understand that via ARC, I can build my routine and give it a name. and then load it to robot. Next question, is how to trigger it reliably ( I will have a keypad near the door, when correct code is typed, I would like it to trigger the Routine) ? Thank you for your guidance,

Proteus · Answer

I would use an Arduino instead of EZ-B. Its a shame to use an EZ-B for such a simple task. Regards.

thetechguru · Answer

Quote:I understand that via ARC, I can build my routine and give it a name. and then load it to robot. This is not accurate. ARC or ARC Mobile needs to be running on a PC or mobile device in constant communication to the EZ-B. This gives you all of hte power of a real computer rather than the limited instructions of a micro-controller like an Arduino. The EZ-B itself has no memory or ability to run stored programs. There are literally hundreds of options then for triggering something because you don't need to just manage the inputs that the EZ-B can take, but can use anything that can communicate with a PC as well. Alan

CochranRobotics · Answer

Really, there are a ton of options for this. A script can run non-stop that is monitoring for events. An event could be a pir sensor switched or really any sensor, or even a file placed on a hard drive. Anything pretty much could trigger the script to then run another script in a different thread. You can have as many scripts as you want to have that can each either work with other scripts or work independent of other scripts. Think about this... You could train the face of the individual when at the front desk. From there, when the person goes to the room or whatever it is, it could recognize the person, greet them, open the door and do whatever else you want it to do. You could have up to 254 rooms all working in this way all communicating back to the same copy of ARC. It would probably take you less time to setup the project to do this than it would to install a pre-built system, seriously. The added benefit would be that the cameras could trip when a PIR sensor trips outside of someones door. This could be used for security. Messages could be played for the guests through the speaker that is specific to the room that the person is in. If you just want to unlock the door, use an arduino. If you want to get creative about what you want this to do, and add the ability for you to expand on this as much as you want and as new ideas pop into your head, go with the EZ-B.

hakemrb · Answer

Hi all, Thank you for your patience. OK for Arduino will do it being a simple task. I am more in a mindset to get into learning what can be done, via robotic platform and change a few things every now and then. I will rather go for the EZ-B as to expand from there. Also, the style of the robot is more appealing as I am not confident that with Arduino, I can do something good looking for the guests to take pictures and be impressed ! TechGuru, That clarifies it thank you ( the triggerring scripts / + wifi ) The PC controls it via WIFI. So the idea is to trigger via the PC , which gives options. Can this PC be in the cloud somewhere and have a local IP on the WIFI local network ( like VPN) ? ( previous post, was referring to microphone on PC instead of on Robot) CochranRobotics, Thank you for all these possibilities. I will get a device first and start experimenting. I'll share here as soon as I get something interesting

thetechguru · Answer

Quote:Can this PC be in the cloud somewhere and have a local IP on the WIFI local network ( like VPN) ? ( previous post, was referring to microphone on PC instead of on Robot)  Yes, or you can port forward ports 23 and 24 to the EZ-B 's IP address, although I would not recommend that because port 23 gets a lot of hack attempts on any public IP adress. EZ-B has a speaker but not a microphone, so yes, for any voice control it uses the PC' s microphone. There are options for doing that remotely too, although it unfortunately gets a bit complex (I have yet to find a simple WiFi microphone solution. Maybe DJ will make one someday). Alan

WBS00001 · Answer

@hakemrb If you want to have a computer on board the robot to allow it to act on it's own without having to be wirelessly tied to a PC somewhere else, you could use a mini PC (One which is small and fits into a small box). Then, you would control it remotely using a VPN over your WiFi setup. The mini PC would, in turn, connect to the EZB-4 via the same WiFi setup. This would be easiest if they all were in client mode. By running the ARC program on the on board mini PC and accessing that program from another PC (laptop or desktop) you can make changes, control the robot, write scripts, etc. and simply leave it running when done. The robot is then running entirely on it's own with no need to be wirelessly tied to a fixed computer somewhere else. The WiFi connection can also be used to transmit notifications to other computers as needed to alert you, the human, to any problems it may have or simply relay information about what it is doing at a given moment. Heck, it could send you text messages even. Maybe call you up on the phone. And, of course, speak to you directly if you are nearby.

hakemrb · Answer

Thank you guys ! working on it still

hakemrb

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