1.2 Single-board Computers (SBC)
In the previous section, you have read about different vendors and different microcontrollers for building a robot. In this section, you are going to see about single-board computers. You know the microcontroller is a microcomputer, right? It has the same component that you can see on your computer. You can perform tasks such as sensor data processing, motor interfacing, etc using microcontrollers. The computation power of the microcontroller is very low compared to our personal computers.
If you want to handle a high-end sensor like a camera, Lidar, you may require more processing power and it can’t be done in a microcontroller platform. In this situation, you can either do the computation on a laptop or you can find another computing unit that can give the same performance as your laptop.
The computation modules that you use in robots should be compact and it should not take much power resource from the robot. It should not have much weight too. The kind of computers which satisfy the above requirements are called single-board computers. This makes the SBC as an ideal choice for robots. Even though it is not powerful in terms of computational power, but it can achieve most of the things that can be done with a PC.
Let’s have a look at some of the popular SBC used commonly in robots. You can also see the comparison of the board’s specifications. The specification of SBC is the same as your personal computer. It is having CPU, RAM, Storage, etc.
Here are the few SBC we are going to discuss in the upcoming section.
2. Odroid boards
1.2.1 Raspberry Pi vs Odroid XU4
The Raspberry Pi series of boards and Odroid board series are entry-level SBC used as robot brain. In this section, you can see the comparison of the latest SBC from the Raspberry Pi foundation called Rpi 4 and the Odroid XU4 board from Hardkernel. You can see the image of these boards below, and the comparison of the important specification. This comparison can make the selection easier.
| Specifications | Raspberry Pi 4 | Odroid XU4 |
| Processor with speed | Broadcom BCM2711, Quad core Cortex-A72, 64 bit SoC@1.5GHz | Samsung Exynos5422 Cortex™-A15 2GHz and Cortex™-A7 Octa core CPUs |
| RAM | Up to 4GB RAM (choices are 1 GB, 2 GB and 4 GB) | 2GB LPDDR3 RAM |
| USB Ports | 2 USB 3.0 and a USB 2.0 ports | 2 x USB 3.0 Host, 1 x USB 2.0 Host |
| Connectivity | Gigabit Ethernet, Dual-band Wi-Fi, Bluetooth 5 | Gigabit Ethernet, Optional Wifi and Bluetooth |
| Display Port | 2 micro-HDMI ports (supports 4K displays) | HDMI 1.4a for display |
| Power Consumption | 5V/3A | 5V/4A |
| Price | From $35/£34 | $49.00 |
Here is another detailed comparison between Raspberry Pi and Odroid.
1.2.2 Jetson Nano vs TX2 vs Xavier
The Raspberry Pi and Odroid were for entry-level robot brain. If you want to do heavy computational applications like robotic vision, deep learning and motion planning, you may need a high-end SBC like Nvidia Jetson series boards. Here is a comparison of 3 of the boards from Nvidia. This will help you to choose the right brain for your robot.
| Specification | Jetson Nano | Jetson TX2 | Jetson Xavier |
| Processor (ARM) | 4-core ARM A57 @ 1.43 GHz | 4-core ARM Cortex-A57 @ 2 GHz, 2-core Denver2 @ 2 GHz | 8-core ARM Carmel v.8.2 @ 2.26 GHz |
| GPU | 128-core Maxwell @ 921 MHz | 256-core Pascal @ 1.3 GHz | 512-core Volta @ 1.37 GHz |
| Memory | 4 GB LPDDR4, 25.6 GB/s | 8 GB 128-bit LPDDR4, 58.3 GB/s | 16 GB 256-bit LPDDR4, 137 GB/s |
| Storage | MicroSD | 32 GB eMMC 5.1 | 32 GB eMMC 5.1 |
| USB | (4x) USB 3.0 + Micro-USB 2.0 | (1x) USB 3.0 + (1x) USB 2.0 | (3x) USB 3.1 + (4x) USB 2.0 |
| PCI-Express lanes | 4 lanes PCIe Gen 2 | 5 lanes PCIe Gen 2 | 16 lanes PCIe Gen 4 |
| Power | 5W / 10W | 7.5W / 15W | 10W / 15W / 30W |
| Price | 99 USD | 412 USD | 712 USD |
