Raspberry Pi Zero W review

Not long ago, I saw a very interesting question on a Q&A website, "How to evaluate the new Raspberry Pi Zero W in 2017?" Not much.

This result can probably be guessed for some reasons. First, the Raspberry Pi Zero W has just been launched, and the supply is relatively tight; especially as the main purchasers of the Raspberry Pi Zero W are just engineers and student friends, so the problem is Come on, who in this group is willing to buy the original Raspberry Pi Zero W? You know, the Raspberry Pi Zero W is one of the most popular in foreign countries.

As for myself, I am very lucky to get the Raspberry Pi Zero W that I have "favored for a long time" without spending any money. Let's talk about the actual experience with you.

The Pi Zero W I got is also "elegantly" decorated with a case designed by adafruit. For a bare board like the Raspberry Pi Zero W, this case is just right. It seems that the person who used it for me is a board lover.

However, when you really experience something, you will find that this thing really can’t be judged just by looking at it. The bottom case of adafruit is very tight, and it took a lot of effort to buckle the board to produce deformation. I was afraid that the board would be damaged, so I simply gave up the urge to take it out and take a look, so this case is not practical at all, especially since the external signal interface of this board is not used to lead out the pin header. It is embarrassing to not be able to remove the board in this case.

But after understanding, although I can't take out the board, it does not affect the introduction of Pi Zero W, because from the design drawing, Pi Zero W only uses a single-sided PCB layout, that is, the front we see is all. Good luck! This makes the board look more compact, and there is no space around it. For the PCB Layout engineer, it must have taken a lot of effort to design, which is worthy of praise.

Another point that needs to be explained is that the above animation is not reflected, that is, the board is equipped with WiFi/BT wireless function, as shown in the figure below.

This is also what the article said at the beginning. Compared with the Raspberry Pi Zero, the hardware improvement of the Pi Zero W is mainly here. This is using the same Cypress BCM43438 WiFi/BT wireless as the Raspberry Pi 3. Chip that provides 802.11n Wi-Fi and Bluetooth 4.1 connectivity.

In addition, Pi Zero W adds a CSI interface on the basis of Pi Zero, which also makes the board layout more compact. For specific changes, please refer to the following animation.

If you carefully explore the hardware design of Pi Zero W, you will find many surprises. For example, in this WiFi/BT solution, where is its antenna? Nervous comrades probably didn't notice this, because the antenna design this time is very novel, perhaps you have never seen it before. This is the design by the Swedish antenna expert Proant AB.

Amplify the position of the antenna

On the PCB of the Raspberry Pi Zero W, all 6 layers of copper foil at the antenna position are hollowed out to form a trapezoidal "hole", which looks a bit like the nozzle of a hair dryer. The part, surrounded by vias and several tiny capacitors, forms a 2.4GHz resonant cavity. Driven by the capacitors, the entire design constitutes the Pi Zero W's antenna. Most importantly, it is said that the performance of this antenna is better than The ceramic antenna on the Pi3 is better, and it blows so badly, I will test it myself later to see if it is bragging.

The actual features of the Raspberry Pi Zero W are as follows:

BCM2835 processor, 1GHz frequency, 512MB RAM
BCM43438 WiFi/BT chip
micro-USB power connector
micro-USB OTG interface
miniHDMI port
Composite video and reset expansion interface
Fragile CSI camera interface
micro-SD card holder for operating system
40-pin GPIO expansion interface
Size: 65mm*30mm
Power on use

When I really wanted to use the Raspberry Pi Zero W, I suddenly found that it was quite embarrassing. The "general-purpose" interface does not need anything. In the real sense, to realize the operation, you need to prepare a few things, such as:

miniHDMI to standard HDMI cable;

microUSB to USB HUB hub, after all, you need to connect a mouse and keyboard;

If you want to connect wired Ethernet, you also need to prepare a microUSB OTG interface to Ethernet interface cable on the board, but there is a MicroUSB OTG interface on the Pi Zero W. If you really want to use it, you need to connect the USB HUB to the mouse and keyboard. The hub is taken into account together, in short, it is necessary to buy, buy, buy.

In this way, the overall use cost is not low, and if you can't buy the Pi Zero W at the original price in China, the use cost is no less than or even more than the Raspberry Pi 3, which is a tragedy! ! !

I still do what I need to do and start testing the Raspberry Pi Zero W directly. As for the performance, I will not test it. To be honest, the performance of the Zero W is very low, similar to the first generation of Raspberry Pi. If you want to know more, you can refer to The previous Raspberry Pi-related evaluation articles of Iban.com (its own performance and the performance gap with the latest Raspberry Pi 3):

The transformed Raspberry Pi B+ - which one is better, the red board or the green board?
Kung fu is in the details - Raspberry Pi B+ evaluation
Not satisfied with being a learning toy - belated optimization of Raspberry Pi B+
Raspberry Pi Quick Start Tutorial
In fact, think about it carefully, the development of open source single-board computers has become today, since the high-performance Cortex-A73 processors like ARM have become common in development boards, and then go to an ARM11 core (Raspberry Pi Zero W) cares about performance, this is not a hooligan, so the next test is mainly to look at the wireless signal that blows into the sky.

I believe that what everyone is most concerned about is the wireless signal gap between the Raspberry Pi Zero W and the Raspberry Pi 3, so the Raspberry Pi 3 is the most suitable for the following comparison objects, and because of the relationship between the Raspberry Pi 3, I can save money I went to buy an adapter cable or something. All the configurations were set up through the Raspberry Pi 3 and connected through SSH, so that it can also be used seamlessly on the Raspberry Pi Zero W. The specific process will not be described any more. I believe that those who have played the Raspberry Pi are familiar with these operations.

The specific test method is to select 6 sample points, and use the Raspberry Pi Zero W and Raspberry Pi 3 to test the WiFi signal strength of these 6 points at the same location. The test results are as follows.

In the test, except for the C sample, there are some problems. Other samples show that the signal strength of the Raspberry Pi Zero W is 3~6 dBm higher than that of the Raspberry Pi 3. Although the improvement is not very large, it does reflect the antenna of the Raspberry Pi Zero W. The signal is stronger than the ceramic antenna on the Raspberry Pi 3. In terms of Bluetooth, the author also repeated the test. The main test signal reception strength indicator RSSI, the Raspberry Pi Zero W is also stronger than the Raspberry Pi 3.


In general, the Raspberry Pi Zero W does have things that are worthy of recognition, such as price and wireless signal strength. Although its performance is far inferior to the Raspberry Pi 3, as a portable and compact open source single-board computer, Raspberry Pi Zero W has the best and widest ecosystem of open source single-board computing. If you can get the board at a normal price, you don't have to hesitate to start it directly. For the pursuit of performance, in addition to learning and development, it also If you want to watch movies, browse the web, etc., I recommend you to buy a Raspberry Pi 3, and I believe it will not disappoint you.