With our new web show called Science Bros. | Saviors of Humanity on YouTube, we needed a low-cost robot hand controlled at distance for our weird robot. So, we used a flex sensor combine with a servomotor attach to a cheap lexan hand. I must say I was skeptical about the hand at first, but I think it will do the job for what we intend to do with it.
What is a flex sensor?
Well, the word flex it’s not for nothing here. It’s pretty simple when you flex the sensor it will increase the resistance and send a signal to the controller you are using depending on how much you flex the sensor. So, it’s ideal to use in a project when you want to follow the movement of a finger, for example. That’s probably what we will use in our robotic hand drone that we want to build as soon as we have our 3D printer. We want to build a full robotic body that will be controlled remotely so that will be really handy. In this project, we used the 2.2-inch flex sensor from Spark Fun for about $9US. There is probably some cheaper on amazon or somewhere else. Check every site carefully when you are buying sensors and actuators like that. You may have found so good deals sometimes.
Like I said before, we want to make a real robotic body and for that we would have needed at least five flex sensors and 5 servos to recreate the motion of one hand. But for this quick project we just needed a simple hand with one simple movement. That’s why we bought the Lynxmotion Robot Hand A at 22 CAD on Robotshop.com. The material is in lexan and it doesn’t really look like the picture. That’s why I have doubts about it. When I received it, the pieces were all burned with the film plastic stuck on it. But anyway, like I said, it will do the job for this project.
What is pretty nice with the hand is that there are servos who fits perfectly with it. The Hitec HS-422 Servo Motor. With just a bit of adjustment, it fits well on the hand and I was surprised. The servomotor is a motor that will position himself depending of the signal he received from the controller. There are 3 wires connected to it. One for the power source, one for the ground and one for the signal.
I won’t do a long lesson about how to plug it and program it, because there are plenty other sites where you can find the info. I just used an Arduino Uno and since I’m lazy I used an already made program. Anyway, it’s so much an easy program to understand that writing it would be a waste of time. Same thing for the electrical diagram. But if you guys tell me that you would be interested that I show you how and do a tutorial about it, I will do it with pleasure! But for now, just type the words, servos, flex sensors and Arduino on Google and will be alright I think. Send me questions if not.
At first, I add some problem with the servo positioning. Indeed, it wouldn’t move because I didn’t fix the servo shaft at the right position with the hand. So, it didn’t move. After fixing this, the hand would move like a charm.
Advancement on the Project
So that’s it for this part. Next time I’ll show the actuator that will move the hand. It’s a really powerful actuator for progressiveautomations.com. I’m really excited to show you that. For my Patreons, I will send you more updates really soon about it. For everyone else, don’t worry the first episode of Science Bros. | Savior of humanity is on the way and you don’t want to miss that! Meanwhile don’t forget to subscribe to our YouTube Channel and other social media. Like and share, it will help us by our 3D printer faster! Thanks a lot again for all the support and talk to you all soon!
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