A wireless headset without speakers? Discover how Sound Band can open your ears... Read more
This project was successfully funded on September 13, 2013.
3rd party feedback and DMAs
We received the third party feedback on our SB5 schematics. This might really interest some but others...not so much. Most all of it is really great news and one step closer to getting the boards to production!
• Power Supply. There were a couple of corrections to the power supply that had to be made. Easy fix; completed.
• Battery Charge Circuit. We were offered the choice to change a resistor value or completely remove the existing circuit (taken from the EVB schematic) if a 200 mA charging rate was deemed acceptable. We chose to eliminate the circuit and use the built in charger capability to simplify the design, reduce parts count (remove 1 transistor and 3 passives), thereby increasing reliability and reducing heat during the charge process. The transistor was fairly large and we were able to recover some space on the PCB as a result of removing this (redundant) circuit. Completed.
• Reset Circuit. We were advised that the reset circuit taken from the previous design was redundant and could be removed. The new chip has an internal reset circuit and it's #Reset pin may be left unconnected. We removed the reset circuit by eliminating its transistor with 4 passive components and we recovered a corresponding amount of PCB real estate as a result.
• Power On Circuit and "Enter" Button. We were advised that we similarly did not need a transistor based circuit used for the Power On button which was taken from the previous design (it worked but was unnecessary). We removed it and we picked up additional board space as a result.
We continue to route the board and are incorporating the schematic feedback suggestions.
Another review with the changes and then we can send the boards out for short-run production scheduling. While we await more robust DMAs from our supplier as outlined in the last update, we have been experimenting with potting materials for the DMAs so that they will withstand the pressure in the production over-mold tool. We are scheduled end of next week for shooting more samples at the plastic injection molding facility.
Mechanical drawings are still underway. The board dimensions were finalized at 15mm x 72mm. We elected to upgrade from the 3.5mm jack to a 2.5mm jack to fit the footprint of the board. Sound Band will come with a 2.5mm to 3.5mm cable.
At this time, we are on track to assemble the beta-tester units at the end of March/beginning of April.
The Hybra Team
Ryan, Joe, Marty, and Meagan