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Benewake TFmini Plus LIDAR- Manual in PDF here

About this Manual

This manual provides all the essential information during the usage of this product.
Please carefully read this manual and make sure that you fully understand everything herein.
The maintenance of this product should be done by the professional technician, and the product can only work with the factory spare part for ensuring the performance and safety.
This product itself has no polarity and over-voltage protection. Please properly connect and supply power as described in this manual.
Operating temperature of this product is between -20℃ and 60℃. Do not use it beyond this temperature range to prevent malfunction.
Storage temperature of this product is between -20℃ and 75℃. Do not store it beyond this temperature range to prevent malfunction.
For ensuring the product performance, do not open the product shell or remove the IR-pass filter.

Conditions with Potential Malfunction

Detecting object with high reflectivity, such as the mirror or the smooth floor tile, may cause a system malfunction.
The product will malfunction if there is any transparent object between it and the detecting object, such as glass or water.
The product will malfunction if its emitting or receiving IR-pass filter is covered by the dust. Please keep the IR-pass filters clean.
Please do not spread ethyl alcohol on the IR-pass filters, which are made of acrylic, IR-pass filters will be damaged.
Please do not pull the fine wire, the wire may be damaged.

2 Description

Product description

TFmini Plus is a milestone of Benewake in the process of promoting the cost-effective -LiDAR. Apart from low-cost, small-size and low-power-consumption, TFmini Plus also improves the frame rate, introducesIP65 enclosures and optimizes various compensation algorithms. These new characters greatly expand the application fields and scenarios of TFmini Plus. The product is compatible with both the UART and I2C interface. Different interfaces can be switched by commands.

Principle of Distance Measurement

TFmini Plus is based on TOF, namely, Time of Flight principle. To be specific, the product emits modulation wave of near infrared ray on a periodic basis, which will be reflected after contacting object. The product obtains the time of flight by measuring round-trip phase difference and then calculates relative range between the product and the detection object, as shown in Figure1.

Figure 1 Schematics of TOF Principle

Key Characteristic Parameters

Table 1 Key Characteristic Parameters of TFmini Plus

① Operating range based on a standard whiteboard with reflectivity 90% in indoor condition
② The distance measurement here is absolute accuracy, and the specific repeat accuracy will be described in the next section 2.4.
③ 3.6°is the theoretical value, from which the actual value will be different. The theoretical divergence angle is 6°.
④ Only frame rates meeting the formula–1000/n (n is positive integer) can be set. The default frame rate is 100Hz.

Repeatability

The TFmini Plus’s range repeat accuracy is directly related to the strength value measured and the output frame rate (frequence). The ranging repeat accuracy is characterized by the standard deviation of ranging. The average ranging accuracy of the TFmini Plus can be estimated by the following formula:

Distance_STD[cm]  =  p00 + p10 ∗ x + p01 ∗ y + p20 ∗ x^2 + p11 ∗ x ∗ y

In the formula, x is log10 𝑆𝑡𝑟𝑒𝑛𝑔𝑡ℎ, y is log10 𝐹𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑒[𝐻𝑧], p00, p01, p10, p20 and p11 are constant coefficients, and the values are as follows:

p00 = 0.9758
p01 = 1.175
p10 = -0.6072
p20 = 0.09501
p11 = -0.2904

The above formula only calculates the average reference value. There are some differences in actual results due to differences in each product.
For your convenience, add a simple statistics table for this query, as shown below:
Table 2 Statistics: the standard deviation of detected distances

Note: the unit of AMP is a.u., the unit of frequency is Hz, and the unit of distance standard deviation is cm.