Around all micromouse players in the world, the magnetic buzzer from PUI Audio SMT-0540 is the most commonly used for a long time due to its compact size and great sound quality. The package yields 5x5x2.1mm size which is the smallest I can find with proper power supply range and loudness.
Earlier this week I recieved an E-mail from digikey about the release of the new version of PUI’s mini buzzer: SMT-0440.
Explained by its name, SMT-0440 is sized at 4x4x2.1mm compare to 5x5x2.1 for SMT-0540. It also removed the dummy pin that on the SMT-0540, therefore only 2 solder leads are remaining for SMT-0440 which makes the solder pad more like a regular SMD inductor now(Although magnetic buzzer is essentially a inductor).
This is defenitely a good news for me since the smaller size will always be helpful for PCB design with limited space, such as half-size micromouse.
Other than the size difference, the output power level is also slightly lower than SMT-0540 as a trade off with a smaller size.
Here are the differences between SMT-0440 and SMT-0540:
Model: SMT-0440 SMT-0540
Sound Pressure Level: 70dB @ 3V, 10cm 78dB @ 3V, 10cm
Current Supply: 90mA 100mA
The picture above shows the size difference in layout mode in Cadsoft Eagle.
Notice there are 2 sub versions of SMT-0440 where one is SMT-0440-T-R which has a hold of the top for sound to come out, and the other one SMT-0440-S-R, has its sound hold on the size(only on one side).
It’s a lit late for me to use SMT-0440 for my GreenGiant V4.3 mouse since I’ve already complete the design. However, I will definitely use it for Green Giant V 4.4 since I am planning to integrate a Bluetooth 4.0 IC along with either external vertical antenna of on board ceramic antenna(no invert F antenna because there is no space available at all 🙁 ) on my existing extremely compact PCB. It is always challenging to put more stuff within the same space, isn’t it? 🙂
I can’t wait to use this tiny creature on my next project.