Building a robot arm – Days 3 and 4, finished prototype

Alright, so the robot arm that me and Mark Laatikainen were building is finally finished. After a lot of… adjusting, we managed to finish the prototype successfully. There were some changes to the initial plan, so here’s a summary of our progress.


To control the arm we had planned to use potentiometers because of their simplicity and accuracy. However, we were presented with the possibility to use a Nunchuk (the Wii remote that is), so we just had to take the chance.

Nunchuks are fitted with an accelerometer that can measure motion and tilting. We decided to connect the Nunchuk to the two main servos that do the heavy lifting. So now when you tilt the controller horizontally or vertically the arm responds. One of the biggest problems we encountered with the accelerometer were the uneven values it provided. We had to implement a sliding average into the code and some if/else- conditions to filter out the erroneous values. The arm is still a bit “jittery” because of the faulty values but it’s manageable.

A close-up of the “Wiichuck” component used to connect the Nunchuk

We use four servos in the arm and we couldn’t connect them all to the accelerometer. So we allocated the analog stick to the third servo and the fourth servo, that controls the “claw”, to the trigger button “Z”. The controls work fairly well with this configuration.

Here are some pictures of the final setup:

The finished arm – Not pretty but quite functional

I had a lot of fun with this project and I’m glad I got to work on it with Mark, who’s a very capable programmer and very competent with electronics. Mark uploaded the code for the arm on his GitHub-page. Here is a list of the parts we used:

2 x Tower Pro 9g micro servos

2 x Tower pro MG995 servos

Arduino Uno

Prototype shield for the Arduino

Wii Nunchuk

Keyes Wiichuck


4 x Metallic shelf holders

Flexible plastic

Dental floss for the claw (yes…)

∞ jumper wires

Remember to also check out this course taught by Tero Karvinen:

-Oliver Lahti

Building a robot arm – Days 1 and 2

I’m attending a second course based on Arduino development. The objective is to build a prototype in five days. This time I’ve partnered up with Mark Laatikainen and together we’re building a controllable robot arm.

An early sketch – Professional, as always

We decided to use Tower Pro micro servos and potentiometers to control the servos. At first, joysticks seemed like the best choice, but we switched to potentiometers because of their simplicity.

Here are some pictures of the early build and a quick video:


Stay tuned for the finished prototype. In the meanwhile, you can check out the course taught by Tero Karvinen over here:

-Oliver Lahti

Finished product

So we managed to finish our IoT-device, the weather lamp. Because we didn’t have a shade for the lamp we wrapped it up in toilet paper and put it in a plastic bag. Very professional.

Nonetheless the device works. It checks the temperature in Helsinki and changes its color depending on the results. We tested it with other cities too and it worked well.







Here are the components we used:

1x Arduino Uno R3

1x Breadboard

1x Keyes RGB LED

4x jumper cables

1x 180Ω resistor

The course was organized by Tero Karvinen and you can check it out here:

I made the lamp with Tomi Laakkonen

You can also get all the necessary code for the lamp here:

If you want to learn more about Arduino, you can also check out the book written by Tero over here:

-Oliver Lahti

IOT, Arduino and everything in between.

I’m currently attending a course on making IOT-devices using Arduino Uno, a simple microcontroller board. The objective is very simple: create a functional embedded system that uses the internet in some manner, a.k.a make an IOT-device (IOT=Internet Of Things). As a complete beginner to programming, electronics and, well, the internet, this course has proven quite challenging to me. However, I’m lucky to have a helpful and patient teacher (Tero Karvinen) and many fellow students that are willing to assist.

On the course we work in pairs. As a project me and my teammate (Tomi Laakkonen) chose to create a RGB LED lamp that changes color with the temperature in Helsinki. We named it “weatherlamp” (yes, quite original). In short, we programmed the Arduino board to fetch the current outdoor temperature from Openweathermap and depending on the degree, the RGB LED changes its color. The project really is quite simple but I at least have learned an immense amount about programming and the basics of IOT.

Yes, it really is this simple

I’m still in the middle of the project but I will be posting the finished results here. In the meanwhile you can check out the course coordinated by Tero Karvinen here, I heartily recommend it:

-Oliver Lahti