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Make Life Accessible

13 Posts authored by: rsc
Here it is, I put the electrical components in a box and bolted it to the arm, added a power switch and a reset switch to the box. ...
To complete the touch lamp for the shelf I made a small box from balsa to match the shelf. The power for the lamp is a small flat 2300mah USB phone charger LiPo battery pack. The schematic for the circuit is shown below: ...
After a week of modifying the original gear train I decided to start over with a fresh set of arm struts with thicker oak trim. This added some needed stiffness and let me embed the shaft bearings deeper into the wood.  The system is still a bit wobbly, but it's working.  Here's a short video of the mechanism running. Since I'm using the PMSM_Demo software as a base for my code, there is a lot of overhead that makes even little changes time consuming. I tried to use the FreeMaste ...
I needed to attach the shelf to my workbench next to the computer so I could update the software easily. I removed the clamp from the monitor arm parts and bolted it to the ELapShelf, here's a photo: After modifying the software to simply move the shelf back and forth 90 degrees, I found that the torque was too much for the motor control and it would shut down in the middle of a movement. To remedy this, I've added bearings to each gear shaft. Here's a pic of the small gear shaft with beari ...
To make the ELapShelf even more useful, I've decided to add some accessories. The first will be a touch activated reading lamp. The lamp will be powered from 5VDC and be controlled using a NXP PCF8883 Capacitive touch proximity switch IC that was included in the Make Life Accessible kit. The basic circuit (taken from the NXP PCF8883 data sheet) is as follows: I used a SparkFun SOIC to DIP 8 pin adapter PCB along with a few Rs and Cs to wire up the touch control. I don't need to run the sw ...
The gears on the shelf are not working very well.  I need to add bearings to the inside shafts to lower the drag and torque on the motor. Lining up gears with just shafts in holes in the wood is a bit tricky. The current solution looks like this: For the next blog I'm hoping to be able to show a video of the shelf operating. ...
Last week was a busy one, not much time to work on the ELapShelf project. I found a nice gear set from an old printer that should work for the shelf control. The small gear shaft was smaller than the shaft on the kit motor however, so I had to make a new shaft adapter. Here's a picture of the gears in place on the main arm and shelf. Here's a picture of the assembly with the gears installed. The arm is made from oak trim so it is strong but not too heavy, and the shelf is a sandwich o ...
To get the software part of this project going, I loaded the motor control demo program and KSDK into Kinetis Design Studio. My first challenge was to wire up the kit button board and to have the software adjust the motor speed using the arrow buttons. I chose to use PORTC pins PTC8-11, since they were the easiest to connect to from the top of the motor shield.  I added a small breadboard with terminals to plug into the motor shield along with pull-up resistors and decoupling caps as sho ...
Got a nice box of parts in the mail today. I had to chuckle a bit at the random length of red wire.  ...
While waiting for the kit parts to arrive, I've been collecting possible assembly components including an old CRT monitor stand and some oak strips/rods/U-bolts/etc. The structure needs to be sturdy enough to handle the weight of the tabletop and contents, but not so heavy that it can't support it's own weight. ...
A few things to consider with this project: 1) The motor is too fast - a stepper with a gear reduction would be a better choice 2) The motor is heavy - will probably move the motor to the mounting end of the main arm and use a belt or wire drive to actuate the folding arm.   I've been taking apart some old printers looking for appropriate gear components.  A nylon worm gear 1:100 would be perfect. ...
There are several software toolchain options to choose from for this design challenge Kinetis Design Studio IAR Keil GCC and OpenSDA(CMSISDAP/mbed I’ve used the mbed compiler in the past for NXP LPC1768 EFM32 Giant Gecko and  FRDM-K64F projects https://developer.mbed.org/handbook/Firmware-FRDM-K64F My first objective will be to use the Kinetis Design Studio for this project, along with the Kinetis Software Development Kit (KSDK). I’ve found many documents and software tools for ...
Abstract: The purpose of this Design Challenge is to develop a device to solve an issue related to restricted mobility from illness or disability.  The constraints on the project include use of the components provided in the kit, including the NXP FRDM-KV31  development board and FRDM-MC-LVPMSM. motor control board. This entry is for a Motorized Articulating Table Top for bedside or wheelchair mounting. Background: I've been in the situation before where I had to stay in bed fo ...