I thought I’d write an update so you guys know what goes into producing the new Thumper throat microphone TH100 belt-pack. Just a warning, this is a lot of info and not everyone cares about all of these details.
1) Create Schematic Drawings - The schematic is a blueprint for the circuit. It’s a “logical” drawing, not a “physical” drawing. It’s used to show what is connected to what, but not how they are connected. The schematic uses symbols to represent each component in the circuit: chips, resistors, capacitors, connectors, etc.
The schematic for the TH100 is complete.
2) Lay Out Printed Circuit Board - The printed circuit board (PCB) is one of those green boards you see inside electronics and computers. The part that makes it green is called the Solder Mask and actually, it doesn’t have to be green! The Thumper board will be a different color, but I won’t say what color…it’ll be a surprise. All of the components of the circuit will be soldered (attached) to the board. There are tiny wires (called traces) and connections (called pads) etched into the PCB, that will connect the various components to each other. The PCB has been laid out (or drawn) for me by an engineer I’ve hired who specializes in this task. The PCB layout for the TH100 is 90% complete, and should be done in the next day or so. Once complete, my engineer will generate a set of “Gerber Files” that tells machines how to make and assemble my circuit.
3) Select PCB Manufacturer/Assembler - The PCBs (and all the traces/pads) will be made by a manufacturing company and then the parts will be soldered onto the PCBs. The Thumper TH60-TH75 models used to have 17 large components that were all “Through-Hole” components. I used to assemble every circuit myself (all you really need is a soldering iron and some solder). The new TH100 has about 100 components, about 90 surface-mount technology (SMT) components, and about 6 through-hole components. The SMT parts are far too tiny for me to solder by hand, so I will hire an assembly company to built the boards using a variety of automated machines.
Until I have the Gerber Files, I cannot really select an assembler, because they quote the order based on the contents of those files. Assembly will actually be where the most money is spent, sadly. Assembly of each unit could easily cost more than all the parts on the PCB and the PCB itself combined. I have spoken with several assembly companies now, and they’re all awaiting my files.
4) Manufacture/Assemble Prototype - This is essentially the same as how Assembly will go for all 100 units, but we’ll only make a couple prototype units. There is almost always a problem with the first “draft”, so we don’t make the whole 100 yet.
5) Test Prototype - Test the prototype and revise the PCB, if necessary. Then go back to step 4 and repeat until tests OK.
6) Order Parts for Assembler - I’ll order parts to make about 105 TH100’s and kit them all up and ship to manufacturer/assembler. The photo below is of loose SMT components. The parts I provide to the assembler will not be loose like this but on reels of tape or in tubes.
7) Manufacture and Assemble - Manufacturer will make the PCBs and assemble all the parts.
8) Test boards - Assembly company will test the boards to make sure they power up and pass audio using a test EEPROM I will provide (more on EEPROMs below).
9) Customize & Order Enclosures - The plastic belt-pack enclosure that houses the PCB must be customized for the TH100. The top panel of the belt-pack needs to have holes drilled in it so that the connectors and mute switch can poke through. A rectangular portion of the side needs to be cut out, too, to give the user access to the DIP switches for configuration. I have already started to work with the enclosure company to get these holes cut exactly right.
10) Program EEPROMs - The chip inside the belt-pack that processes the audio is a tiny digital signal processing (DSP) computer. I have been programming the DSP chip and once we’re ready to ship these mics, I will write the program onto an EEPROM chip, which is like a very tiny flash drive that stores the program. I’ll program (or burn) the chips using a special EEPROM Programmer. The EEPROM chip is “socketed”, which means it sits in a socket on the PCB and can be swapped out. I will be shipping out software updates periodically to the users. My original plan was to use microSD cards to store the program, but it got complicated real fast and not worth the extra effort. I have purchased the USB EEPROM programmer and am ready to burn some chips!
11) Final Assembly - When the PCBs arrive here, I’ll insert an EEPROM into each one, insert the PCBs into the enclosures, screw them shut, and test them out.
12) Ship! - This one is fairly self-explanatory.
So there you have it! I’ll be posting more details as I go through each step of the process, including photos and videos. I’ve already talked to one assembler nearby about allowing me to video-record the assembly process as the Thumpers are made! Yeah, I’m a dork.
Strap It On!