The "$50 Robot" Tutorial with the Roboduino

Original $50 Robot Tutorial written by :

This $50 Robot tutorial has been modified for users of the Roboduino microcontroller board.

      Before beginning the $50 Robot Tutorial we have to understand that this robot will not actually cost $50. It will be slightly over $50 after taking into account shipping.
This tutorial assumes that you have the Roboduino microcontroller board. The Roboduino uses the same main microcontroller as the original $50 Robot Board. The $50 Robot Board in the original $50 Robot tutorial would have to be made by the user and requires complex soldering and without any modification ,does not take advantage of the full capabilities of the microcontroller. The Roboduino takes advantage of all the capabilities and is pin compatible with the $50 Robot Board.
     The Roboduino is more expensive than the $50 Robot Board, but the Roboduino is easier to put together, requires the only basic soldering skills, and possesses much more functions than the $50 Robot Board.
     I would suggest beginners to follow the original $50 Robot Tutorial if they want a crash course on robotics , but if they want to jump right into robotics without any difficult soldering then they should definitely get the Roboduino. In addition the Roboduino is a great investment since it will be used for years to come and on many different robotics/electronics projects.

To purchase the Roboduino go to :  . We ship internationally.

Here is a picture comparison of the $50 Robot Board and the Roboduino

                $50 Robot Board                                                      Roboduino


Step by Step Robot Tutorial

The $50 Robot Tutorial is divided into sections . By each section I will include a link to the original $50 Robot Tutorial Section and they write any notes on modifications that should be done for use with the Roboduino.


Step 1 - Basics
In this part, we will talk about the motivation behind building such a robot, what you will learn in this tutorial series, what the robot will be able to do, and the parts required to be purchased.

Step 2 - Mechanics
In step two, we will build the chassis of your robot. This part can mostly be done with parts around your house, and has room for creativity on your part. There are many ways to do this, I offer only one of them.

Step 3 - Electronics
The electronics steps are perhaps one of the simplest parts of the $50 Robot Tutorial. While the original $50 Robot Tutorial requires you to make your own microcontroller board from scratch, this $50 Robot Tutorial for the Roboduino does merely requires you to assemble the Roboduino and plug in the battery.

Step 4 - Programming
Now that you have done the hard part, sit back and relax as programming will be simple. Better yet, this step is 100% free! Download the software, plug in your robot, upload the code to the robot controller, and away it goes!


Step 1 : Basics

Step 1 : Basics


Original Link :


Notes and Modifications:

Most of the parts listed on the "Required Parts" section are not needed .

Here is the Required Parts list for the $50 Robot Tutorial when using the Roboduino:

Item Cost each ($) Quantity Website, Part #
Hitec HS-311 servo
(modify the servo)
8.99 2
1.62Kohm resistor ( thats what I calculated)
calculate the correct resistor value for use with your photoresitors using this tutorial:
.49 5 pack
CdS Photoresistors 2.99 5 pack RadioShack
NiMH Battery Pack
11.96 1 All-Battery
# 11106
Roboduino Microcontroller Board ( Kit Version - needs assembly, but you can also get the Assembled Version for $15 dollars more)
39.99 1 CuriousInventor


Optional : AVR MKII Programmer  - $34  Digikey# ATAVRISP2-ND

Step 2 : Construct the Chassis

Step 2: Construct the Chassis


Original Link :



Notes and Modifications:

No modifications

Step 3a : Construct the Controller

Step 3a : Construct the Controller


Original Link:


Notes and Modifications:

This section is probably the hardest for someone building the $50 Robot Controller and probably the easiest for someone using the Roboduino. 
You can basically disregard this entire section. Just know that this is how you plug in a battery into the Roboduino. Heres a picture of how to connect it.


You must also set the power jumper to be external power. Just follow this diagram and set the Roboduino to be powered by External Power Input.


Step 3b : Construct the Controller

Step 3b : Construct the Controller


Original Link:


Notes and Modifications:

Once again , Roboduino users have it really really easy. Just skip this entire step, it doesn't apply to Roboduino users since they have the Roboduino - the best microcontroller board for the ATmegax8 series.

Step 3c : Construct the Controller

Step 3c : Construct the Controller



Original Link:




Notes and Modifications:


Skip the parts about testing the controller board. Just plug in your battery into the Roboduino. Plugging in the servos are extremely easy. Just plug in the servo header into Pin 5 and 6, the ones marked PWM. Plug the servo header in with the yellow part of the header facing towards the center of the board.


Also if you haven't yet done this(you were instructed to do this in Step 1 of the tutorial, follow the part that details choosing the proper resistor value for the photoresistor. Then just plug in the photoresistors analog pins to Analog Pin 0 and Pin 1.



Here is that part, I copied and pasted it here for your convenience




Now you must make two photoresistor sensors. Go to the photoresistor tutorial and
follow the detailed instructions. I used a 1.5kohm resistor for R with the middle
sized photoresistors in the RadioShack kit, but your situation might be different so you might

want to recalculate your R value.


professional method and makes your sensor more modular (can be scrapped for future robots).
The disadvantage to it is that the crimping tool can be a little expensive.

You dont need to do the crimping method described to make this sensor, but its a better method.

Step 4: Program the Robot

Original Link :


Notes and Modifications

Follow all the software related stuff ( installing , etc.) One major thing to note is that you CANNOT use PonyProg to program your Roboduino. However you can use the AVR MKII ( aka ISP2) Programmer detailed on that page AND you can even use no hardware programmer at all and use the Roboduino's built-in bootloader! Using a bootloader means you just plug in the Roboduino's USB cable and program the Roboduino through its own USB port, no extra programmer needed.

Also , since the Roboduino uses the ATmega168 we have to modify the original $50 Robot code. The modified code lets you have 16 times the processor speed as the original $50 Robot code. Please note that this code is ONLY for the Roboduino. Just download code that I already modified for you - its attached at the bottom of this page.


6 Pin ISP Programmer

Just connect the ISP programmer's USB cable to your computer and auto-install the drivers (Windows XP downloads and installs it automatically). Then plug in the 6 pin ISP cable into the Roboduino , making sure that the arrow on the ISP connector matches up with the arrow on the Roboduino board.



Now in AVRstudio you just press the Build button -



Once the build is successful

Press the program button -


A program window should pop up. Select the MKII Programmer and then another window should open up.


All the fuses were already set for you when the Roboduino was made so you don't have to worry about fuses. In the main tab make sure that it says ATmega168.

Now click the Program tab and verify that the Input Hex File is your Photovore Hex File. Now press program and everything is done.



Unplug the ISP connector and your robot is ready to go.



To be written soon


roboduino_source_photovore_v1.zip195.44 KB