In Depth Otto Robot Step by Step

I have created this Otto Starter Robot for a college robotics class and while there are a few other Instructables that I have seen on how to build the Otto robot, I hope that I can be a little more in depth about the building process. Before starting any of the steps, I would recommend reading all of the way through first just to be able to get an idea for how you will need to build your Otto. For example, I needed to drill two holes in the back of the Otto so that I could mount the power button and the speaker. How you desire to build and set up your Otto will determine how you should begin.

For the supplies of this build, you can order the kits from the Otto Robot website at Otto DIY. There are two types of Otto kits to choose from with one only including the electronics of the robot (motors, wiring, etc.) while the other kit includes the shell with the electronics. If you purchase the electronics only kit, you will need to be able to 3D print the shell and the files you need for that can be found at Printables.com. In addition to the kit, you will need a few tools to make this build a little easier such as: a magnetized mini-phillips head screwdriver and wire strippers. I also used electrical tape, a drill, and pliers on my build. As a side note, I purchased the electronics kit only and 3D printed my shell.

Before doing anything else, the servos need to be aligned. To do this, take one of the connectors that comes with the servos and turn them left until it stops. Next, turn it to the right until it stops. Finally, turn it to the left and try to get it to the middle. If done correctly, you should be able to turn the servo to the right or left an equal distance to get it to stop. After completing the calibration process, leave the servos in the middle.

If you need to make any modifications to your Otto, this is the point in which you will complete those modifications. For example, you may want to put the button to activate your Otto in a different location so you may need to drill a hole or determine how you want to mount it. An example of some of the modifications I made included drilling a hole for the power button so it would fit properly. Another thing that I did was drill a hole to thread the speaker wire through so that I could place the speaker on top of the head so that it would look like a little hat. If you don't think that you need to make any kind of modifications to your Otto that may be more difficult later on, then go to step 3.

To attach the Nano ATmega328 to the Nano shield I/O you will need to put both of the ports on the same side and align the pins from the nano to the slots on the shield and push down. Be careful that you push straight down and not to the side as that may bend the pins. Also, be careful not to cut your hands on the Sauder points on the Nano when pushing down.

The ultra-sonic sensor will need to be inserted in the slot on the face of the head. You will likely need to tilt the sensor at about a 45-degree angle so that it can slide into the groove. Once you have it properly installed, it may wiggle around a bit, but it should remain in place.

The nano/shield is mounted into the head, and you will need to tilt it at about a 45-degree angle and align the ports on the nano/shield with the head and slide it in. Use 4 of the small screws to hold the nano/shield in place.

Retrieve one of the servos and insert the servo motor into the body portion of the Otto on either side ensuring that the small axle aligns with the keyed slot. After successfully inserting the servo on one side, use 2 screws to hold it in place and then repeat this process for the other servo.

The images are of the right foot but the same applies to both feet. A little white piece that I call a half connector (seen in my hand) needs to be inserted into the groove on the foot with the large hole having the grooved side facing towards the interior of the foot. The servo is then inserted into the grooved hole and a screw is placed through the outside hole of the foot, through the connector and into the servo to hold it in place. Repeat this process for the left foot as well.

To attach the legs to the body, you will need to install a full connector inside of the leg as shown above. You will more than likely need to cut the connector to fit. For the front portion, I only cut off about two holes of length. For the rear portion I only left two holes of length. When installing it, ensure that the grooved slot on the connector is facing towards the bottom of the robot towards the servo. Once slotted in, attach it with a screw. Repeat this process for the other leg.

Start this step by threading the cable from the servo in the foot through the leg and through the slot in the bottom of the robot chassis. Then attach the foot by sliding in onto the bottom of the leg. The foot has a slot in the front of it that will fit onto a little piece that protrudes from the leg. This may require you to slide it on at somewhat of an angle to get it to fit. Once placed, the servo inside of the foot can be screwed into the leg as shown in the picture with the screwdriver. Repeat this process for the other foot.

I found a diagram accessible through the link below that can assist you in wiring up the Otto robot. I have also included photos that I myself took while wiring up my robot. The servo motors should be wired first since those are the easiest to do. The ultra-sonic sensor should be wired next using f/f connectors. The power button will come next and as you can see, I wired the power button for a 9v battery. (Side note, the diagram for power does not show how to wire for a 9v battery. The wiring for power that I am showing is specific for a 9v battery compared to other forms of power one might use. You will need to determine how to wire it differently if you have a different power source.) I attached the adapter to the battery and then wired it red to red on the button, then black wire on the button to the vin hole on the mainboard. I plugged the other black wire from the adapter on the battery into the hole marked "g" on the mainboard. As a test, press the button and a light on the mainboard should come on. Press the button again and the light should go off. After this, I plugged in the speaker to the pins as marked on the diagram.

Finally, you will need to place the top part of the Otto on to the bottom part and ensure that the little clips catch. Now your Otto robot is complete!