I have received my SDP Mini RPlidar Experimental Platform that I ordered on Seeed Studio Store. SDP Mini is basically a mini robot that you can use for navigation, mapping purposes. This article will help you build your navigation robot using with or without the SDP Mini.
Basically, SDP Mini is a Slamtech designed RPLidar combined with a navigation system. The core function is the Lidar, but with a navigation system you can accomplish a lot more. If you want to use the SDP Mini instead of building one, you can check it out here.
First, let’s take a look at what functions you want in your personal robot:
- Sensor System. Submarines uses Sonar system for detection underwater. But that would be too complication and expensive for a small project. Instead we choose a Lidar system, which is much more convenient in distance configuration and mapping.
- Navigation System. You need the robot to move around, duh! Don’t worry, for this, we won’t use a system in robots like Atlas or Big Dog, which have fantastic motor and balance control that allow them to move on rough terrains. For this one you can choose wheels or treads kits.
- Computing System. You will want to collect the data and possibly analyze it. Let’s be frank, how can one call a machine robot without computing system on board?
Lidar System
For Lidar System, you need it for mapping the surroundings and navigate safely. There are many Lidar system available on the market. You should not that there are two-dimensional mapping systems as well as three dimensional ones. You can choose which one to use basing on your preference
Here I listed 2 Lidar on the market and their basic stats.
Basic Stats:
- Low Cost 360 Degree Laser Range Scanner
- 4000 samples/s 10Hz
- Range: 6m
- Rotation speed: 600 RPM
- Resolution: 0.9°
- Requires at least 1.5A@5V
Basic Stats
- Range: 40m
- Resolution: 1cm
- Sample Rate: Up to 1075Hz (500Hz default)
- Field of View: 360°
- Rotation Frequency: 1–10Hz (Adj.)
- Interface: 3.3V (5V tolerant) UART TTL
- Power: 5V @ 450mA to 650ma
- USB Plug and Play
- Weight: 120 grams
Navigation System
As for Navigation System. If you want to move your robot on flat terrain, for example on your floor, you can use wheel-based. However, if you want it to run on rough place like outdoors or a small, bumpy slope, I would recommend you use a tank-tread based navigation system.
Below is a Tank Tread Kit from VEX EDT. Of course, you will need more than this to build a navigation System.
As for the power, you can use DC battery based like SDP Mini does. And you should choose your motor and motor drive accordingly to ensure compatibility.
Computing System
Sometimes, a computing device might be already included with the Lidar. However, you can still attach another piece like raspberry pi, to achieve other functions. For example, add both a camera and pi to your robot, you can record video from its perspective. At the same time, it would help if the it is not integrated in the Lidar system.
Here’s a raspberry pi I recommend you to use:
Basic Stats:
- Processor: Broadcom BCM2837
- CPU Core: Quadcore ARM Cortex-A53, 64Bit
- RAM: 1 GB
- GPU: 400 MHzVideoCore IV®
- Network Connectivity:1 x 10 / 100 Ethernet (RJ45 Port)
- Wireless Connectivity: 802.11n wireless LAN (WiFi) and Bluetooth 4.1
- USB Ports:4 x USB 2.0
- GPIOs 2 x 20 Pin Header
- Camera Interface: 15-pin MIPI
- Display Interface: DSI 15 Pin / HDMI Out / Composite RCA
- Power Supply (Current Capacity):2.5 A
As you can see, there’s a lot utility you can get from such a small piece of hardware. You can even add a camera module on your pi, so you can see things from your robot’s “eyes”
Assemble them together part by part and voila, you have your own robot! Cheers!
