Whilst single LEDs may be sufficient for small 'indoor' projects, machines in noisy factories or 'outdoors' may require more intense visual and sound actuators for communication with their human masters.
This device uses a 'Push-Pull' chip (see components section) to effectively beef up the ampage available to the LEDs / sounders. Trying to run 8 LEDs from one MCU pin will burn out the circuit!
The PCBs are reversible so one side can be used for the LEDs and the other for sounders. I joined the two PCBs together with cable ties in the photo.
Video coming very soon!
The module was tested in a very noisy environment - a small workshop with a 90 dB petrol engine running inside. The beepers were far louder than the engine and their rated power of 97 dB seemed accurate. The banks of LEDs were literally dazzling and the whole thing soon became extremely annoying!!
The PCBs arrived super quickly from https://jlcpcb.com/ .... Cost $2.5 plus postage and are super good quality - no problems with silkscreen as with other suppliers.
The PCBs are reversible, with LEDs on one side and sounders on the other, the idea being to join them together as shown above. The lower PCB has 4 sounders on the RHS and the 10 pin driver chips are hidden on the other side.
Whilst the LEDs could be hand soldered fairly easily with a hot air gun, the sounder casings tended to melt so a reflux oven would have been more appropriate although I ended up using solder paste and soldering iron.
A bit of trial and error selecting the correct resistors for the banks of LEDs. Red and green required 100 ohms and the others about 40 ohms (see instructions section).
The whole PCB works really well and nothing gets too hot and the LED banks are incredibly bright! Watch this space for a video update with the device on an actual machine - the WEEDINATOR - where the sounders need to compete with the noise of a 90 dB petrol motor.