Introduction: Tower Climb Helping Robot V1 - Two Legged, RF, BT Control With App

When ever seeing lizards on walls i plan to make a robot like it. It is a long term idea, i search lot of articles for electro-adhesives and check some way and failed of its capacity of holding. Just for now i plan to make it using electromagnet to climb in the tower. While visit to the wind mill tower found if some small tools they never taken to the top they again want to get down and take it again. So why cant we make a helping robot to walk in the tower and reach the top with tools. When search in the web found some wheeled robots. but it want some wide surface to move. So i plan a robot with legs walk up. At first i plan for walk like lizard but it also take some more space. In the current plan it walk in a straight line of even in a 2 cm metal bar. So even in the frame wind mill also it climb easily.

I use RF module in this project to control a long distance. But if i want to develop a RF transmitter with basic circuit its more work and not customization. So i make a base station with RF transmitter and bluetooth module. So Android app control the robot in the long distance through the bluetooth base station.

Note after complete the project:-

Basic plan of the robot working correctly with out 3d print parts. But adding 3d print parts make the robot fall down due to magnet power not sufficient to hold the weight and also the lifter servo not able to lift the weight.

Step 1: Materials Required

Materials Required

For Robot

  1. Arduino Mini Pro 5v. - 1No.
  2. RF receiver - 1 No.
  3. Mini MP1584 DC-DC 3A Adjustable Buck module. - 1 No.
  4. XY-016 2A DC-DC Step Up 5V/9V/12V/28V Power Module with Micro USB. - 1 No.
  5. 18650 Battery - 2 Nos.
  6. MG90S servo - 4 Nos.
  7. DC 12V KK-P20/15 2.5KG Lifting Solenoid Electromagnet - 2 nos
  8. 3d Printed Parts (even with out 3d print also we make it)
  9. Male and female header pins
  10. Slim wire (i got it from usb cable its hard and very slim)
  11. Plain PCB.

For Base Station

  1. Arduino Nano - 1 No.
  2. RF Transmitter - 1 No.
  3. HC05 Bluetooth module - 1No.
  4. Male and Female Header Pins
  5. Plain PCB.

To assemble robot and Base station we need 2mm and 3mm screws and nuts, Container for Base station.

Step 2: Plan and 3D Print

Its a simple construction even with out 3d print also we make the robot with pop stick and hot glue gun. If you have 2 nos of pan and tilt assembly then add the electromagnets that's the plan.

I make the pan and tilt in ball shape that's the only difference. If you want it simple use the pan and tilt assembly.

Step 3: 3D Print Files


After receive the parts only i found its weight high so problem in holding and lifting. So don't use this model directly if you can, use it as a base and made modification for magnet and Lifting with two servos in each side and test. I going to check it in second version.

Step 4: Circuit Plan

Two circuits want to built one for base station and another for robot. Robot circuit has 2 parts power circuit and control circuit.

Step 5: RF Base Station Plan

Base station circuit is a simple circuit with Arduino nano, HC05 bluetooth module and RF transmitter all this are powered using a 9V tin battery. Connect the Arduino tx and RX to HC05 RX and Tx then power of HC 05 from arduino 5V and gnd. For RF transmitter as per Radio library use D12 for transmitter and connect the power from battery, because as per increase in power transmit distance also increase, max input voltage for RF transmitter is 12V.

Step 6: RF Base Station Build

As like all my projects make a shield for arduino nano. This is the base circuit want to make a container after all the test is ok and robot walk on the wall.

Step 7: Robot Circuit Plan

The challenging task in the robot circuit built is all the circuit want to be kept inside two rectangular box in the root arm, its internal dimension 2 Cm X 1.3 cm X 6.1cm. So first arrange the circuit and find the way to make a connection. As per my plan i divide the circuit into two circuits control circuit and power circuit.

Step 8: Robot Control Circuit

For control circuit we only use arduino pro mini. If a male and female header is used over the board the height is near to 2 cm. So with only male connector over pro mini i directly solder the wires over the male header. I always reuse the micro controller that's why i don't directly solder on the board. Take 10 wires out from the board as per plan

  1. Vin and Gnd from battery.
  2. 5V, Gnd and D11 to RF receiver.
  3. D2, D3, D4, D5 to servo motors.
  4. D8 and D9 to control electromagnet using uln2803 IC.

Each group wires are end with male or female connector as per opposite side joint. Example use male header for servo because servo comes with female connector. Hot glue the wires joint to avoid soldering broken during working. I use wire from usb cables (data cable) that wire is very slim and hard.

Step 9: Robot Power Circuit

This robot wants 3 type of powers 7.4 v for arduino, 5.5 v for servo and 12v for electro magnet. I use 2 samsung 18650 batteries it 3.7 X 2 = 7.4V a dc to dc step down board to regulate the powder to 5.5V and a DC to DC step up board to get 12V to reduce the side connection given as per diagram.

Arduino Data pin has max 5V so for control electromagnet we want a relay or transistor circuit all it need some space. So i use ULN 2803 Darlington transistor array IC it occupy less space. Gnd is conencted to pin no 9 and 24 v supply connected to pin 10. I connect the D8 and D9 of arduino to pin 2 and pin3. From pin 17 and 16 gnd connection to electromagnet and 24 v direct to electromagnet.

Like control circuit, power circuit also have male and female header as per control circuit.

Step 10: Circuit Pinout

Pin out of control circuit and power circuit is show in the figure. Now we simply connect the headers after fix it in the robot. Its take some time for 3d print to receive so currently i test the robot with a simple setup.

Step 11: Check Circuits

I use Arduino uno to upload program to mini. Lot of details available in net for doing it, i make a shield for it. Then as like base plan i hot glue the servos and the magnet but the problem is magnet not stick with the servo. But able to test all servos and magnet. Wait for the 3D parts to come.

Step 12: Develop Android App

This is my 13th app in MIT App Inventor. But this is a very very simple app when compare to my other projects , because due to the robot want to walk in heights i dont want the robot to walk continuous steps. So if press one button it move one step. so for all directions a arrow mark provided. The app connected to the base station using blue tooth and send the below code for each direction to arduino. That base station send the code to the robot using RF.

Letters transmit as per key press in the app

Down - D

Left Down - H

Left - L

Left up - I

Up - U

Right up - J

Right - R

Right down - K

Step 13: Android App

Download and Install the Tower climb app in your android mobile.

Click the icon and start the app.

Click pick bluetooth and select the base station bluetooth.

When connected control screen with 8 arrows in arrows visible. Click each arrow to move in that direction.

For Aia File for Arduino use the below link

Step 14: Arduino Program

There are two arduino programs one for Base station and another one for Robot.

For Base Station

Base Station Arduino Program

Use radiohead library to send the data through RF. I use a serial event to receive character from android through bluetooth and once received the char send to robot through bluetooth. Its a very simple program

For Robot Program

Robot Program

Use radiohead library and servotimer2 library. Dont use servo library because both servo and radiohead library use the Timer1 of the arduino so program not compile. Use the Servotimer2 to over come this issue. But in the Servotimer2 Library servo not rotate from 0 to 180 degree. So finally found software servo library working fine. Main thing in the arduino program is atleast one magnet on every time. So if want to walk first release one magnet and then move the servos and then hold both magnets like wise move again and again.

Step 15: Test Run With Out 3D Part

Check the robot function with out 3D parts with manual joint. All functions working correctly. But problem in power supply. Two 18650 cant give efficient supply for magnets and servo. so if magnets holding servo flicker. So i remove the battery and give supply from Computer SMPS 12V. All the functions work correctly. Due to transport problem its delay to get the 3d printed parts.

Step 16: Received 3D Parts

I use tinkercad to design the model and print it in A3DXYZ they are very cheap and best 3d print online service provider. I miss one cover for the top.

Step 17: Assemble Parts

For assemble we need Screws come with servos and 3mm X 10mm screw and nut 11nos. Picture by picture explan

1) First take the foot part and electromagnets.

2) Insert the electromagnet in the holder and take wire from the side and bring it inside the ball through side hole and screw it in the base.

3) In the rotation servo holder insert the servo and screw the servos.

4,5) Fix the servo horn in the rotating top using screws.

6) Fix the hand holder to the rotating top.

7) Forgot to put the hole in the holder base to screw the rotating base with servo, so put a manual hole.

8) Put the base servos as 90 degree and screw the rotating joint with servo. Keep the magnet wire come out as opposite on both legs.

9) Join the servo arm in the robot arm.

10) The hands back connector gap is very high so i use a plastic tube to reduce the gap. Fix the servo and the hands to it. Insert all the cables inside the body of the rotating body and keep the terminals only in the top servo holder.

11) Join the both arm using screw in the center.

12,13) Place the power circuit in one side and control circuit in other side and take the wires out through holes in the base. Cover all the 4 tops. Due to not receive the cover for one top i use coke can bottom to cover it now once receive replace it.

13) In the base already we provide a gap for 1mm fill it with hot glue gun for grip.

14) Now the climbing robot is ready.

Step 18: Check the Function

On Switch on both both legs in 180 degree and magnets on. When i switch on and put it in my steel birol it hold it tightly i feel very happy. But when i click to walk up in the mobile it fall down. I feel very sad, check and found all the functions ok, problem in holding power function detected.

Step 19: Problem in Holding and Lifting

Now put it in the flat surface and test. Both the holding and lifting power needs to increase. So i want to hold the base and help to lift slightly. Want to upgrade the servo and magnets.

Step 20: Run With 3D Parts With Manual Help

Check the run of the robot with my help. Want to upgrade.

Step 21: Basic With Out 3D Parts Walk in Vertical Bero

Step 22: Conclusion

I feel its a nice idea to move in a straight line and move to any direction so it easily climb over the frame type towers also and plan to provide a camera in the second version but the basic requirement is not full fill.

The basic plan worked correctly getting upset when found not working with 3d print parts. Cross check and found as per calculation of weight of 3dprinted parts in online fully differ with the actual 3d printed parts. So plan to do the 2nd version with servo995 and 4 magnets, 2 magnets on each leg. Basic model move straight in a small frame and rotate to any direction. I update it daily while finish the work, so i explain all the process with out think the result. Go through the project and if you have any more idea more than change the servo and increase the magnet power and magnet nos just comment me waiting for your reply's.

Steps Want to take

1) Change Servo from MG90s to MG995 servo.

2) Use two servos for the arm in both sides.

3) Change the magnet with more holding power and two magnets on both sides.

4) For MG995 change the 3d design and reduce the arm length. Increase the circuit holder box size.

Before 3d print estimate the weight and all that much weight in each leg with temporary setup and check.

This take a very long day to complete with failure result, but not told as fully failure because it run with out 3d parts as expected. Want to upgrade the motors and magnets. Working for the version2 with wireless robot climb up to the reach of RF length.

Thank you for going through my project.

Lot more to enjoy...............Don't forgot to comment and encourage me friends.

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