Rover R14 based on a pi top[4]

From the company pi-top I received their latest product, a pi-top[4], in order to build another rover for my RoboSpatium. The pi-top[4] is a Raspberry Pi 4, packaged in a very cleverly designed housing. In this video I do not want to talk about the specs of this brilliant computing device, you can read the numbers on my pages as well as on the pages of the manufacturer. All pi-top[4] ship with the so-called “Foundation Kit” in a metal box. Inside of it you can find sensors and LEDs, a docking platform and other small parts to quickly and easily enter the world of “physical computing”.

00:49 - After connecting a screen, keyboard and mouse, you get a full-fledged Linux computer that hardly misses any computing power for surfing or coding. Unfortunately, my personal favorite construction tool “OpenSCAD” is not part of the official software packages, but a precompiled version is available on the net and can therefore be quickly installed. The program takes a few seconds to start, but as soon as the window appeared you can work smoothly with the software. To my mind, with the Raspberry Pi 4, the goal of offering a full- fledged desktop computer is achieved - software that requires more computing power is at least suspect to my opinion. Slic3r is included in the official Raspbian packages, so besides designing you can also prepare the robot parts for 3D printing with the pi- top[4].

01:41 - Again, the pi-top[4] shows no weaknesses: Slic3r runs smoothly and you rarely get a break and so time to think if what you are doing makes really sense… I spent the next few days designing and printing all the parts for the rover. What are the advantages of a pi-top[4] for a rover project? First of all, I would like to mention the integrated battery. The electronics in the pi-top ensure that the Raspberry Pi shuts down when the battery is low, which prevents deep discharge. The charging electronics is also included - as soon as the special power supply unit is connected, the pi-top starts the charging process.

02:31 - A command line program is integrated in the pi-top operating system, which outputs the current battery parameters and so reduces the necessary programming work. The Raspberry Pi does not have an ON/OFF switch, while the pi-top adds this simple peripheral, so that the rover can be shut down and switched off easily without a network connection. Thanks to the special socket, wiring of the vehicle is done faster than with any of my previous rover projects - the soldering iron is only used sporadically. Two standard servos for continuous rotation act as drive motors. These are connected to the 40-pin header on top of the case - the + 5V pin can deliver currents of up to 1.5A.

03:25 - The camera is tilted by a micro servo - this is also connected to the 40-pin header. The headlight is made of the LED modules from the “Foundation Kit”, which are quickly connected with the cables included - R14 is my first rover with colorful lighting. Since the brightness of the LEDs is not particularly high, I soldered an additional module composed of 4 white LEDs. With that the electronics of R14 would be done, but the “Foundation Kit” also includes an ultrasonic and a light sensor, which I have also installed because wiring it up it is so simple. The images are transferred from a USB camera - the originally intended Raspberry Pi camera module is not so easy to connect, since the corresponding ribbon connector inside the housing is already in use.

04:19 - Pi-top is developing it’s own camera module, which should deliver better results than the inexpensive USB camera I am using now. All modules of the “Foundation Kit” have magnets on the back that fit to special mounts that are also in the box. At first, I melted nuts on my robot parts to attach the modules, but this turned out to be too weak. It works better if the special mounts from the pi-top kit are used. The LED modules of the headlight are clamped with a second plate because the cables are not very flexible causing the LED to get loose when tilting the camera.

05:02 - After the assembly, I had a first test run, whereby I opened the website with the control interface on my pi-top[3]: R14 can move forward… … or backwards… … and turn on the spot by controlling the two motors in different directions. The microservo can point the camera up… …straight… …or down… … and the LED modules illuminate the environment when driving at night. The ultrasonic sensor is attached to the front of the rover and measures the distance to the nearest obstacle. The light sensor does what it’s name suggests: it indicates how bright it is currently in my robot room.

06:07 - Even after upgrading the pi-top[4] with wheels and camera, it can still function as a desktop computer if needed - here I control R14 with the help of itself - its a really mobile computer. Like all my robots, R14 is also accessible via the Internet - simply open the control page in your browser and explore my RoboSpatium - here I am using my smartphone to do so. The whole thing works without registration and is free of charge - at least for you. The lithium polymer battery of the pi-top[4] has a capacity of 2600mAh at 7.4V, which is good for driving my rover for more than 2 hours.

06:54 - To get R14 running continuously, external power is supplied via a power pole with an anti-twist mechanism on top of the vehicle, being connected to 12V DC power. Thanks to the battery, I can send R14 on outdoor missions every now and then to increase the sphere of influence of my RoboSpatium. If you’d like to support me in keeping my robots running, you can click the “Donate” button on my pages - many thanks to all existing supporters. All details of the construction, the 3D files, software and circuit diagrams of this robot are available on my pages. Thanks for watching and: “I’ll be back!” .