In the last few weeks (since I tested out the OLED display), I've been getting all of the last little details in place to move forward with the sleep mask project. Specifically, since the circuits have been finalized, I have been laying out the printed circuit board and making certain that I have all of the necessary components on hand (and putting together an order for those I do not).
The cheapest service I could find is Seeed Studio's Fusion PCB service. For a mere 10$ you get 10 5x5cm boards; an extra 15$ gets you 5x10cm.
After completing the board layout (shown below), I found that it was more than 5x5cm. It is larger than I had hoped, but still reasonable relative to the size of the sleep mask. A large part of its... largeness... is due to the fact that I was designing based on the parts I already had in my inventory. Those parts, in turn, were chosen to be usable across many projects; as a result, they are usually rated for much higher voltages, currents, and dissipated energies than are strictly necessary for this project. This is okay for a prototype, but any future hardware revisions will involve specifying more appropriately-sized resistors and capacitors.
Since I was going to have to pay for an extra 5cm of board, I decided to make the best of it and add a circuit for a project I've had on the back burner for a while. Specifically, I want to build some flashing lights into my bicycle helmet for safety; some of the lights will be ordinary LEDs, but eventually I want to build some EL wire into the helmet to give a real Vegas feel. To do this, I need 'high voltage' (about 20V) to step up to 120V using transformers. While I am still collecting the transformers (I take them out of burned-out CFL lightbulbs, as transformers or even bare magnetics of appropriate size have proven difficult to source), I am going to move forward with getting this board, including the 20V step-up and LED constant-current drivers, layed out and ordered. It is also shown in the image below.
The REM sleep mask board is on the left; the microcontroller is in the middle, with the micro USB connector above, battery charger above right, buck converter right, REM detector bottom left, headphone amplifier left and OLED display top left. The helmet flasher/boost board is on the right; boost top left, EL wire switches bottom left, microcontroller bottom right and LED drivers top right.
The cheapest service I could find is Seeed Studio's Fusion PCB service. For a mere 10$ you get 10 5x5cm boards; an extra 15$ gets you 5x10cm.
After completing the board layout (shown below), I found that it was more than 5x5cm. It is larger than I had hoped, but still reasonable relative to the size of the sleep mask. A large part of its... largeness... is due to the fact that I was designing based on the parts I already had in my inventory. Those parts, in turn, were chosen to be usable across many projects; as a result, they are usually rated for much higher voltages, currents, and dissipated energies than are strictly necessary for this project. This is okay for a prototype, but any future hardware revisions will involve specifying more appropriately-sized resistors and capacitors.
Since I was going to have to pay for an extra 5cm of board, I decided to make the best of it and add a circuit for a project I've had on the back burner for a while. Specifically, I want to build some flashing lights into my bicycle helmet for safety; some of the lights will be ordinary LEDs, but eventually I want to build some EL wire into the helmet to give a real Vegas feel. To do this, I need 'high voltage' (about 20V) to step up to 120V using transformers. While I am still collecting the transformers (I take them out of burned-out CFL lightbulbs, as transformers or even bare magnetics of appropriate size have proven difficult to source), I am going to move forward with getting this board, including the 20V step-up and LED constant-current drivers, layed out and ordered. It is also shown in the image below.
The REM sleep mask board is on the left; the microcontroller is in the middle, with the micro USB connector above, battery charger above right, buck converter right, REM detector bottom left, headphone amplifier left and OLED display top left. The helmet flasher/boost board is on the right; boost top left, EL wire switches bottom left, microcontroller bottom right and LED drivers top right.
No comments:
Post a Comment