Work Night 4.25.19

Work Night

Date:4.25.19
Location: Logan HS
Time: 5:15-7:15 PM
Students: Avery, Tanner, Seth, Alex, Paige, Thomas and Austin
Goal: Test new generator configuration under load.

We have been having more difficulties with our limb tester. We blew a 12.5 microFarad capacitor and need to order a new one. The capacitor is used in motor startup for the tester. All testing stopped until we got it back up and working. Also, some of the bearing and moving parts needed to be greased and refitted with normal wear and tear occurring from use over the course of the year.

Once we fixed the tester we were able to start collecting new data on our 18 V generators and new 12 V generators to see which ones would give us the highest current output. We finished the night by getting most of the data collected and still have to try a mixed configuration (one 18 V and one 12 V generator) wired together to see how that looks. Once all the data is collected we can make a decision on which configuration is the most efficient for us. Keep in mind that our generators are really stock DC motors that we are re-purposing for this application.

Software has made some nice advances and our wireless (Bluetooth) connection is now configured for 2 voltage inputs and one enable (on/off) switch. Bench testing was positive on the setup so we will mount the new board this week and then test it next week with the limb tester and full charging circuit. If that is function, we will have made hit all our targeted goals.

We are still progressing on the patent application. Work is slow as it is new for us. Our industry contacts  have been very helpful here as some of them are patent holders and are very willing to help us with the terminology and process.

New 12 V motors that came in from India. Notice the packaging.

The new motors came with this envelope indicating they were the first motors Portescape had made of this variety. They are still stock motors, but apparently they were the first run.

Motors after we added the pinion gear and extension wiring and shielding. Notice the manufacturing label on them indicating 001 and 002.

Paige and Austin working on the wireless connection circuit board amid the clutter of pizza and treats.

Tanner, Seth and Avery working on the design for the production concept.

Wave form output for our 18 V motors through the charging system. The yellow line indicates the capacitor charging and the blue line indicates the duration of the constant voltage supplied.

Seth measuring Thomas' forehead...not sure what that has to do with the project, but it looks like they are having fun.

Wave form output with our new 12 V motor output through our charging system. The blue line indicates some transient activity is happening toward the end of the wave form. 

Work Night 4.11.19

Work Night 

Date: 4.11.19
Location: Logan HS
Time: 5:15-7:15 PM
Students: Tanner, Seth, Alex, Paige, Austin, Thaying, Avery and Thomas.
Goal: Test the new charging circuit for functionality.

We needed to test the updated charging circuit and had a problem with one generator outputing the correct voltage. It seemed one of the generators was not functioning properly. When we cycled the tester, we were only seeing one output on the oscope. We felt it was a mechanical malfunction, but after some testing we determined both generators were functioning in the new mount we 3D printed with the (gray) supports we added for additional strength. It had to be wiring or some other electrical issue which we will have to trace down next week.

The new 12 V motors will hopefully be in next week with the 8:1 gearhead. We are hoping this adds to the durability of the generator system. The current motors we are using have a plastic gearhead.

Team members also worked on the patent information. We feel something that makes our system unique is the fact that our design does not change need to change foot of the artificial limb by adding motors or gears as in some other designs. This keeps the cost low and increases simplicity . It will work on any Freedom foot which we were told is the most popular prosthetic foot. The only thing that may need to be modified is re-3D print the heel adapter for the size of the heel. Which would cost pennies.

We also spent some time redesigning the charging port that goes in the vacuum pump. The current one is proprietary and is big and bulky. We needed to design a more streamlined one that would not be so bulky. Students found a way to modify the current adapter by doing some cutting and drilling some new openings and then using epoxy...at least that is the current plan.

UPDATE 4.15.19
We worked on troubleshooting the motor and electronics to try to trace down the fault in the circuit that was giving us zero output from one of our generators. It turns out one of the green terminal blocks was mislabeled and therefore we wired one of the generators in wrong. This was the reason we showed no output from that generator on the oscope. When we corrected it you can see the output was back to what we expected. In fact, it worked exceptionally well. The output was giving us the voltages we needed and was charging the caps and we demonstrated that by lighting up some LED's to show how the system worked. Using our safe (low charge) setting we were able to light the LED's in about 15 sec.

The oscope shows the output from our generators to our storage system.  This is important because it shows
the success of our charging system. Now we just have to tweak the software.

New supports for the motors in gray.

Thomas and Alex working on the LED array.

Seth, Tanner and Avery working on redesigning the charging adapter for the vacuum pump.

Work Night 4.4.19

Work Night
Date: 4.4.19
Time: 5:15-7:15 PM
Location: Logan HS
Goal: Complete further testing on the charging system and begin to write the patent.
Student: Alex, Thomas, Austin, Paige, Seth, Avery, Caitlin, Tanner and Paige.

We broke another gear on one of the generators on Monday so we repaired it and tested it again and it seemed to work. We have isolated the problem and need to support the gear housing better from the heel strike impact force. We are working with stock motors and plastic gears. Some of this is to be expected. A production model would incorporate metal gears and a larger diameter motor shaft. Our current one is 22 mm.

We also did some testing with a new 10 lbs spring attached to gear which resulted in about ⅓ of the voltage of previous spring so out output was lower. We will need to go back to our 20 lbs spring to increase our voltage output. We also had something go wrong with the charging circuit and our positive cap doesn’t charge properly and doesn’t discharge properly. We double checked labeling and connections on system diagrams and checked connectivity and solder joints

Tanner, Caitlin, Avery, and Austin worked on the patent. They are working on defining our abstract definition and also added more information about the software to the summary of our patent application.

Caitlin also worked on making some additions to the layout of the app (added more clear and visible constraints to the text).

Friday- 4.5.19  Update: In testing the charging circuit we found that some solder joints needed to be corrected, but most importantly one of the super capacitors appears to be damaged. Otherwise circuit works perfectly! This was a risk area as we are operating outside the specs for surge voltage, and it is unclear if the technology will support the high currents. We can modify the circuit to reduce stress but retain the full capacity. As an alternate, we could have a full electrolytic cap bank, but it would be physically larger.

Alex and Thomas troubleshooting some electronics.

Students working on the patent application.

20 lbs spring on the left and 10 lbs spring on right.

Seth adding support structure for the generator mount.

Work Night 3.28.19

Work Night

Date: 3.28.19
Location: Logan HS
Time: 5:30-7:15 PM
Students: Alex, Paige, Seth and Thomas
Goal: Test the charging system to see actual output with our new storage unit.

It was one of those nights where a below average test result and an equipment failure caused us to "fail forward". One of the generator gear heads snapped off while testing. It looked like the screw just pulled out causing it to happen. There was plastic on the treads so we cleaned it off and relocated the hole to secure the gear head. It appeared to work in another test.

The outcomes we were looking for with our testing as far as current levels generated did not happen. We are not sure if it is a mechanical problem or the generator mount is slipping. We need to supply charge a 1000 mA battery and right now our output is 50 mA for 4 seconds. When you do the math, it means it will take around 10 hours of walking with two generators to fully charge the battery.

This is two high and of course if we added two more generators it would cut the time to 2.5 hours of walking but we were hoping for a better outcome. We need to modify the mechanics and introduce a greater load into the system to see what it really will do.

With all this said we are pleased with our progress. Our invention will supply enough energy to support the SmartPuck battery and our BlueTooth connection without draining the battery and still charge the battery. We just want to decrease the charging time.

We have some ideas on how to move forward for next week.

Motor output captured on the scope.

Scope showing storage unit stepping up the voltage as it builds in the capacitors. This is what we want to see.

Starting to sheath generator output wires to protect them. This is fun to see happen because it means we are nearing completion.

Generator wires now sheathed to protect them.

Seth waiting for a 3d printed modification to our heel adapter.

Alex and Paige setting up a bench test.

Alex introducing a load into our system to simulate the battery of the SmartPuck.

Thomas working on electrical schematics to clean up our hand written ones.

Work Night 3.21.19

Work Night

Date: 3.21.19
Location: Logan HS
Time: 5:00-7:00 PM
Students: Avery, Thaying, Thomas, Alex and Seth
Goal: Work on finalizing the energy storage system and test it.

With spring sports in full swing we have to start our work nights later to allow many of our team members to get their practice in before we have our meeting. It makes for some long days and late nights but we continue to move forward as we near our target date for completion.

Tonight we wanted to bench test our new energy storage unit. The old unit worked ok in our previous tests but we wanted to experiment with super capacitors. We have never used them before on a project and Mr. Foye (our electrical engineering consultant) suggested we give them a try. It took two weeks to design, build and test the circuit but it worked. Now we have to mount it on our limb tester to give it a walking test.

What we want to see is the unit store the electricity created by our generators and then slowly discharge it. You will see a video below that documents that charge dissipation. By storing more electricity we hope to power both the SmartPuck battery and our BlueTooth module. We met our goal earlier by generating enough energy to power the battery, now we just want to see if we can improve it to also power our wireless connection.

Next week will be the big test to see if it works with our limb tester.

Thomas worked on cleaning up some of our electrical sketches that were done on paper.

Paige and Alex documenting the testing of the storage circuit.

Image of the new storage unit being tested before we mount it. In our new configuration, we are using 22 milli Farad Super Caps and 7500 micro Farad electrolytic capacitors. All the probes you see are running to an oscilloscope. 

Alex soldering in the final connections on the storage unit.

Seth working on a new adapter for the shock absorber  for the production concept.

Bench test showing the slow discharge of the super cap storage system. The power supply is disengaged and the voltage will slowly discharge to zero.

Work Day 3.11.19

Work Day 

Date: 3.11.19
Location: Logan HS
Time: 10:00-Noon
Goal: Finalize storage system and work on the design for the production prototype.
Students: Seth, Austin, Alex, Caitlin, Thomas, Avery

Today the students had a day off school due to PTC but came in anyway from 10-Noon. We needed to work on the "production concept" which is just a 3d printed model of what we envision the final prototype to look like. We also needed to finish the storage circuit with the super caps in place.

Alex worked on the storage circuit which is very time consuming as it needs to include the rectifiers (a lot of diodes) to function. These components all had to be put in individually and then soldered in place.

We have the App controls worked out to include an on/off, voltage monitor coming into the Buck Boost system and battery life in the form of a percent.

We are beginning to switch gears to incorporate time for patent writing and final testing. What we want to get from our final testing is the time it takes to charge the Smart Puck battery in how many foot cycles.

Thomas demonstrating the size of some of the surface mount components that we are working with.

Seth getting some measurements for the production concept model.

Alex soldering some surface mount components and jumper to the bottom of the buck boost board. As you can see, this is very detailed work.

Austin and Avery working on the Nano BlueTooth module.

Schematic showing the LTC modification that we are building.

Work Night 2.28.19

Work Night

Date: 2.28.19
Time: 4:30-7:00 PM
Location: Logan HS
Students: Alex, Paige, Avery, Austin,Thomas and Seth
Goal: The goal for tonight is to test the charging system in its entirety to see if we can output to our phone App.

There was quite a bit of preliminary work done prior to tonights work night. 3-4 hours were put in yesterday and today working on the Super Cap storage system, the BlueTooth circuit and mounting the completed circuit boards on the tester.

The last two weeks have been a series of "fail forward's". We have wanted to test our system but we would have a mechanical gear breakdown, or a poorly soldered joint or a IC problem. We really needed some positive news in our testing tonight to give us a boost and we got it.

We took some time to wire up the charging system and test out our generator to make sure we had functionality. This proved successful so we were going to hook up a 5 V power supply to test the system but we changed our mind and hooked up the generator to cycle the limb tester. This would be our first full system test so a lot was riding on it. We cycled our tester and the BlueTooth connection with our App was enabled. When we read the output of a regulated 4.2 V on the cellphone there was a cheer. 

This proves the system can produce enough electricity to power the Smart Puck voltage requirements!!!

Now we refocus on reducing the size of the circuit boards, design a new mount for the display model prototype, adding in the super cap circuit and working on our patent.

Probably our most important video documentation to date. This shows our charging system fully in action. The BlueTooth connection with our App is enabled and we are reading an output of 4.2 V on the cellphone. This proves the system can produce enough electricity to power the Smart Puck voltage requirements!!!

Paige majorly updated the big book. Then I worked on requesting money from both Mayo and McDonalds. I also started a list of companies we have contacted for Inland Printing. My dad and I plan on talking to some local companies about donation.

Thomas worked on the new Super Cap circuit that will replace our existing rectifier and storage system. He should be done by next week and ready for another test. Alex worked on mounting components and added a new terminal to the charge control system.

Seth worked on the battery holder with LED's to demonstrate the system is charging the battery. He is also starting to work on the new mount for the display prototype.

Avery worked on...well Avery stuff but he said he will make a blog post on Friday.

Austin successfully tested his BlueTooth circuit and is working on reducing the size of it.

Using marine epoxy to attached the pinion gear to the shaft of the 8-1 gear head. The wooden platform is a jig we built to ensure the motor and shaft stay inline while the epoxy sets.

Charge controller circuit mounted at the top of the plexiglass now and ready to be wired.

Austin tightening up connections and mounting circuit boards.

9 V battery holder and BlueTooth circuit board installed on tester. 

Thomas setting up the O-scope for our big test tonight.

Screen shot of the generator output showing almost 10 V with one generator.

Alex wiring the system together for the test.

Our complete prototype system on the tester. Now we work to condense the size and scale and make a model prototype.

Video of Austin mounting circuit boards on the tester.