The Lilypad Scale: The First Home Wheelchair Scale
What?
I did all of the electrical and embedded design for a product that has been sold to over 70 customers as of August 2015 and has multiple 5-star reviews on Amazon.com.
Why?
For wheelchair users, every pound they gain is a pound they have to lift when they want to get out of bed, into the shower, or onto the toilet by themselves. So managing weight is key to independence as well as health.
How?
The wheelchair scale is composed of 4 mini-scales, one for each wheel. It sends data over Bluetooth to a smartphone app. Two strain gauge load cells are read by analog circuitry then an ADC, which transmits data through a level shifter to a BLE113 Bluetooth-enabled microcontroller. I designed all aspects of circuitry, PCB layout, power system, and connectors and wrote all firmware. I optimized the system for low power draw. I integrated with the mechanical system and did DFMA. I iterated the design many times from initial prototype to sellable product.
I did all of the electrical and embedded design for a product that has been sold to over 70 customers as of August 2015 and has multiple 5-star reviews on Amazon.com.
Why?
For wheelchair users, every pound they gain is a pound they have to lift when they want to get out of bed, into the shower, or onto the toilet by themselves. So managing weight is key to independence as well as health.
How?
The wheelchair scale is composed of 4 mini-scales, one for each wheel. It sends data over Bluetooth to a smartphone app. Two strain gauge load cells are read by analog circuitry then an ADC, which transmits data through a level shifter to a BLE113 Bluetooth-enabled microcontroller. I designed all aspects of circuitry, PCB layout, power system, and connectors and wrote all firmware. I optimized the system for low power draw. I integrated with the mechanical system and did DFMA. I iterated the design many times from initial prototype to sellable product.
