Testing Mark V Generator Mount

Testing Mark V Generator Mount

Date: 12.28.18
Location: Logan HS
Time: 9:00-11:30 AM
Goal: Test the newly 3D printed Mark V Generator Mount.

Just a quick post to show the initial test of the Mark V.

We still have some work to do on the actual mount and the motor we are using is inefficient but as you can see from the videos, we are harvesting energy from the heel strike. This is a major step for us as we now will start looking for more efficient motors and using multiple motors to increase the voltage we harvest.

The mount seems stable on the leg and does not move which was a concern. The gearing seems to be holding up to the force of the compression step and our simple linkage (a welding rod) appears to be the correct gauge.

We need to work on aligning the gears with the linkage. Our next mount may move the motor further in line to accommodate this. We also need to design a linkage for the rod to attach to the heel. This will be 3D printed.

This is the old Mark IV Generator Mount

This is the new Mark V Generator Mount. The gears have been flipped to the other side and it is seated farther
down on the prosthetic limb. We shortened the taper because it was creating issues with the foot placement.

Video of the Mark V in action.

Video of the voltage output from the Mark V. It varies from about .8 V to 3 V.

Work Day 12.27.18

Work Day

Date: 12.27.18
Location: Logan HS
Time: 10:00 AM- Noon
Students: Thomas, Avery, Alex and Seth
Goal: Attach the newly 3D printed generator mount and work on the electrical requirements for the buck boost circuit.

It is the holiday break and team members are still coming in to work on the project. Alex, Avery, Seth and Thomas took time out of their vacation to come into school for a couple of hours to work on the 3D mount and some electronics.

Seth modified the generator mount design after we started to attach it to the limb. We found 4 or 5 areas that needed modifications to ensure a nice fit. We called this version of the mount the Mark IV.

Alex and Avery spent quite a bit of time figuring out the best way to attach the bolts into the mount as the tolerance is very small and close. We had to countersink a hole which caused part of the mount to crack. We will build the new tolerance into the next design. They also soldered some wires to the motor to extend the range we can monitor the system from.

Thomas worked on the electrical requirements needed for the buck boost system. We know we will have a small voltage coming in so we want to create a circuit that will boost that voltage into a higher output voltage. A lot of this will be surface mount so the soldering will be finer and more attention to detail will be needed.

We ran out of time to test the system which is probably for the better as the next generator mount will be printed by then and we can use that.

Seth and Avery taking off support material from the 3D print of the Mark IV mount.

Thomas working on the Buck Boost circuit and interpreting datasheets.

Alex and Avery putting the generator mount on the leg.

The Mark IV Generator mount with test motors in place. We are using this model to
learn from so we can print a better one with closer specifications.

Avery and Alex attaching the generator mount.

It is easier to work on the leg when it is off the knee joint to 

attach the generator mount.

Work night 12.20.18

Work Night

Date: 12.20.18
Location: Logan HS
Time: 4:30-7:00
Students: Paige, Avery, Austin, Caitlin, Seth, Thomas and Alex
Goal: Work on mounting assembly for generator, test motors and motor windings and research Nano vs. Uno for software.

We made significant progress tonight in a number of areas. Paige updated the Engineering Journal book and outlined steps for the patent process.

Avery, Caitlin and Austin revisited the Arduino current/voltage divider parameters and looked into switching from Uno to Nano to scale down in size. They will have to test the Bluetooth communications for compatibility. Caitlin is making progress on the MIT App for the cellphone interface.

Seth took measurements and began to design the mounting mechanism for the generator and gears. We decided to just print this in segments to see how it would fit before doing a full 30 hour 3D print. Seth has named this the "Mark III" after the Iron Man movies.

Thomas and Alex tested motor resistance and voltage output for a variety of different motors and logged it in a database. We are looking for the perfect motor which will give us low resistance, high voltage and high current output. This is difficult to find due to compromises.So far we have seen that the ideal generator is: small, able to generate 15 to 25 V without complicated gear train, low winding resistance- able to deliver high charging current in a short time and low bearing losses.

 Thomas then worked on designing a rectifier circuit in Multisim to test different motor wave form outputs. Alex worked on soldering a gear to a motor which was unsuccessful and then used epoxy which worked very well after it dried.

We will next meet on 12/27 from 10:00- Noon over the holiday break.

Seths generator mount with bearing openings cut in.

Thomas and Alex testing motors.

Paige updating the Engineering Journal. 

Thomas demonstrating his rectifier circuit for the team.

Video of the 3D printer working on the generator mount.

Seth showing the first generation of the generator mounting assembly.

Thomas showing how Multisim is used to simulate a rectifier circuit.

Other notes:

Some notes on the idea generation and further direction and the Logan technology project.
First, if we continue to present relevant problems to solve, and solutions are feasible, the students will likely react.

On December 20 we tried to outline apparent intellectual property domains of the work so far:
1) prosthetic leg energy recovery system for recharging battery power
2) unilateral prosthetic foot mounted energy recovery generator system
3) prosthetic leg energy recovery system monitor and controller hardware
4) prosthetic leg energy recovery system monitoring controller software/logic

These elements could be combined in and intellectual property description in whatever manner is appropriate. They are listed separately here for further development in idea content.
The further steps we have identified for meeting basic goals recorded as:
1) complete equipment of the first tester configuration to demonstrate heel strike based energy recovery; this includes adding mechanical linkage, generator, and electronics to demonstrate a complete system
2) supply one or more generators suitable for number one
3) assemble electronics circuit modules for power conversion, battery charging regulation, the microprocessor operation; and display or communication elements sufficient to support display
4) provide necessary frame reinforcement and other provisions to stabilize mechanical operation
5) consider desired improvements for a new model; fabricated of welded aluminum by an outside shop
The last item noted was a possible improvement of the tester to be able to demonstrate a more complete gait including loaded rolling of the foot from fore foot to heel.

At this point if the project is completed meeting these goals, project success would only be limited by the extent of battery recharge that is achieved, and integral communication is supported. The still may be limited by how well the team can find an adequate generator element and provide effective mechanical linkages to engage the generator, possibly including forefoot strike as well as heel strike.

A further possibility is that a second generator could be added, taking advantage of the structure of the carbon fiber bilateral foot design. The second generator could be identical to give further generating capacity, or it could be designed with a different time constant to allow for different gait speeds if necessary.

Of course if a single generator is found which will meet the need, this bilateral approach may not be necessary for charging purposes only.

Another question the team’s been exploring is what is the role of the software and communication system. The obvious first answer is that it is to report the health and operation of the charging system. This does open up the possibility that the data that is available may be useful for other purposes.
At this point, we have heard team members discussing measurement of charging system voltages and the sequencing of processor operations.

So, in total, the prosthetic user would have available information about battery condition as well as the added information of the performance or operation of the charging system. The expectation is that this would improve prosthetic use by allowing simpler management of the vacuum puck charging system.

The team has been asking what other sensors are information might be needed. Before expanding that, it might be useful to think about what used to be made of the data that will already be available!

So possible data to transmit might consist of:

• peak generator voltage/average generator voltage/generation duration/energy generated
• charging current delivered(milliampere hours?)
• Battery condition/battery capacity

Additional information which may be relatively easy to together may include:

• number of generations cycles/steps, or steps per hour(user useful measurement), or steps per day(indicating prosthetic use)
• average generated energy per step(a possible indication of activity level)
• characteristics of apparent gait, including gait interval or symmetry, and intensity or duration(note that these measures may be of use by a therapist or clinician)

Additional information that might be available if a bilateral generation system is used, and with additional data taking sophistication:

• generation waveform transmission, which will include some information of gait details. This would require sampled data taking by the processor and package transmission
• sampling in discriminating data between the two generators, to detect asymmetries in foot loading
• if some of these data elements can be included, with processing and reports delivered by an external computer system.

Intellectual property may become:

1) prosthetic leg energy recovery system for recharging battery power providing clinical diagnostics
2) bilateral prosthetic foot mounted energy recovery generator system
3) prosthetic leg energy recovery system monitor and controller hardware providing clinical data
4) prosthetic leg energy recovery system monitoring controller software/logic providing clinical data and diagnostics

So with very little additional effort, it is possible to show the potential value of the data that is being provided. Some  research papers which describe the clinical practice of helping patients achieve improved gait using the prosthetic legs and the therapy process as they adapt to them.
It also points out that a further interview or discussion with a therapist or clinician should verify some of these goals by practicing medical personnel.

Work Night 12.13.18

Date: 12.13.18
Location: Logan HS
Time: 4:30-7:00
Students: Paige, Alex, Avery, Seth and Thomas
Goal: Solder connections on tester and put it under load to see how it performs deflecting the heel 0-1/2". We also want to see how our software program reacts to higher voltages.

We spent the majority of the time trying to get the tester ready to go when put under load. Paige worked on a footpad to create a heel deflection. Thomas and Alex worked on soldering and connecting the electrical. After a broken drill bit, we mounted the foot pad and were ready to test the "limb tester". Everyone got safety glasses on, Thomas energized the system and gradually brought the torque control to full power. Nothing happened! The motor stalled and would not cycle. We were disappointed. We tried starting the limb at different angles but the motor would not cycle the way we anticipated. Later we got it working better and found we cannot start the motor under any load. If we let it build momentum, it will cycle normally and deflect the heel 1/8"-1/4". Now we have to see if we can increase the load to get the 1/2" deflection we need or we have to get a bigger motor.

Seth worked on Inventor to begin designing a mount for the motors and gears. He made good progress considering he had to re-learn Inventor as it has been a while since he used it.

Software Report:

Before we commit to using an Arduino Uno, we want to make sure it will support our input voltages. This is speculation right now, but we may have input voltages ranging from 10 V to 30 V. The I/O pins on an Arduino only support 5 V so a voltage divider has to be created.

Avery worked on some of the background for creating that circuit.

 Austin has tested some lower voltages with success, but we want to make sure we can go above 20 V if needed by creating the program and circuit to prove it will work.

Block of wood that will be cut to make our footpad.

Paige measuring out the block to cut for the footpad.

Seth securing the arm assembly for the tester.

Alex and Thomas soldering the electrical connections in the boxes for the tester.

In the videos below you will see the first deflection test for the limb tester heel and the video of the limb cycling under load.

Work Night 12.6.18

Work Night

Date: 12.6.18
Location: Logan HS
Time: 4:30-7:00 PM
Students: Caitlin, Avery, Tanner, Seth, Thomas and Thaying
Goal: Wire in the electrical on the limb tester and energize it to see if the artificial limb moves the way we want it to.

It was a very successful work night! We did our first test of the artificial limb tester and after a few wiring issues, everything ran smoothly. Our neutral wire was not connected properly to the capacitor circuit that drives the motor.

The tester still needs to be modified to allow for more of a heel strike. Most of the welds were tacked in to allow us to move components around if needed. Mr. Pitz and his welding students have helped in the fabrication of the tester. We will need to move the hip mounting point out 3/4" so it is inline with the motor mount and cam. We also need to design a trip mechanism that will stop the forward motion of the leg and allow for a more natural movement into the heel strike. The frame of the tester may also need to be reinforced by the hip joint to prevent deflection under load.

A safety light was wired in for the test and will turn on when the unit is running. Some disappointment here as it is a solid LED yellow light and not a blinking light.

Steady progress from our software team. They have programmed and designed a circuit that will monitor battery voltage levels and output them to a computer screen. We now need to program that interface so it is visible on a cellphone App. MIT's App Inventor looks promising right now.

Caitlin has finished the Sustainability training is is preparing to take the test for it which is covered by the Lemelson-MIT grant.

Our goal next week will be to clean up the wiring, design a generator base that is 3d printed and work more on the software end.

Austin wired in a circuit that will sample battery voltage ever second and then display it.

This is a simple version of the battery display circuit.

Austin testing his program and circuit.

Thomas and Tanner working on electrical for the limb tester.

Seth getting ready to test the limb tester. 

Voltage changes being displayed in Austin's program from the battery level circuit.

Thomas and Tanner working on wiring the limb tester before we energize it.

Work night 11.29.18

Work Night

Date: 11.29.18
Time: 4:30-7:00 PM
Location: Logan HS
Students: Thaying, Avery, Caitlin, Thomas, Seth, & Alex
Goal: Begin to wire electrical boxes on tester and calculate the heel spring depression rather than compression values.

Seth drilling holes in tester for motor mount.

Seth wiring in electrical boxes

Boxes and capacitor for motor mounted.

Thomas and Alex working on notes for some compression/depression spring testing.

Avery and Caitlin working on the MIT APP.

Thomas, Alex and Thaying connecting fuse to switch.

Video of Seth drilling in the motor mount for the tester.

Alex and Thomas talked about testing methods and values associated with the heel strike. Piezo largely capitalizes on the heel strike. Our idea will capitalize on the spring depression from the heel. The voltage potential difference are striking. On compression we can harvest 5 j on depression we can harvest 20 j.

Caitlin and Avery explored the MIT App maker and tested the Bluetooth. Austin is making nice progress on that interface and display. We will need to find a way to show a power/energy level in the app.

Thaying worked on the blog.

Seth worked on the tester drilling holes for electrical box mounts and then worked with Thomas and Alex to wire in the fuse (one really well done wire). More work will be done on this on Friday.


Notes from the Hardware Team submitted by Alex M.:

• All kinds of li-ion batteries, need different chips for different types of batteries
• Have range of typically 3.0-4.2 volts

What can we do with tester

• Do a straight heel march for first test
• Can see compression and release of heel
• Force = Spring Constant*Distance + Generator
• More force when heel springs back (depression) rather than the compression
• Our testing doesn’t give accurate representation of release force
• Slowly generate at higher volt or faster at lower voltage. Which is more effective?
• Figure out how to attach heel of  tester to gear box.
• Could have plate on heel > to connecting rod > Gearbox
• Tester will give more accurate representation of what our generation time is.

What are key questions

• Gross generation
• What size capacitor
• High cap, low impedance
• Low cap, high impedance
• Chip max voltage less important because we can change capacitor size
• Some chips have taps for processors
• How does generator results compare to theoretical results
• What are our loss factors?

Table = yellow for release

• 
  

Plan for Testing

• Representative step cycle vs chart
• Is it realistic/reasonable
• Is it feasible?
• Look at return cycle
• Combination of forces and generators
• Where do we go to get good numbers?
• Could test extremes if we feel safe and note the interesting data
• Does it look good? Are we looking in the right area?
• What could be wrong
• Is something broken?
• How to fix it?
• What to we attack to improve efficiency
• Going for simple step to start
• Walk on heels

• If things go well

• What do we test next
• Test then review (Review and critique)  
• Add more components to system (Caps, chips, power circuit)
• Prototype battery load (dummy load{power supply})

Work Day 11.21.18

Work Day-Student came in on a day off school
Date:11.21.18
Time: 4:30-7:00
Location: Logan HS
Students: Caitlin, Avery, Paige, Alex, Thaying, Thomas

We took two steps forward and one back. The software side of the project
showed some promise with Austin successfully using an Arduino Uno and
Bluetooth module to interface with his phone to turn on and off an LED. Next
step will be to change the interface on the phone to show additional inputs.


Avery and Caitlin work on the Kiva software with limited success. We have a
hardware issue where the software does not want to run on our laptops. We
decided to see if Kiva is a viable option by the end of next week. Python
does run on it. We also have to work on our energy budget for the software
end.

Alex and Thomas worked on the locating the “hip joint” hole where a ½” hole
will be drilled in our tester for that pivot point. Calculations will have
to be redone for the motor location. Once that is done, we can begin to
mount and wire the motor.

Paige is making progress on the presentation and social media. She is ready
to go live with the accounts and keeping them updated will be a challenge.

Thiyang put up our first blog post and will have the second by the end of
next week.

The ordering process for tax exempt can be a pain. The same vendor
(Grainger) charged tax twice on our tax exempt account. The first one took
1.5 hours to resolve. The second time they said all states are tax exempt
except Wisconsin (which is not true) and cannot be resolved until Monday, Nov. 26th.

Other things we looked at:

Prosthetic Test System Alternatives
Basis for Force Generation
Direct mechanical thrust
Direct Weight
High mechanical advantage(scissors jack, etc.)
Discussed Alternatives; progress with conversion testing, idea conversion
model, electronics

Conclusions:
 With reasonable equipment, direct energy recovery mechanisms can be tested
With high mechanical advantage fixtures, with limited movement, full force
testing can be achieved. To achieve higher forces, knee joint must be used
in "scissors jack" configuration. Ref:
https://www.engineersedge.com/mechanics_machines/scissor-lift.htm

A variety of test conditions can be created with controlled, limited equipment

Prosthetic Test System Alternatives
Use of Gearmotor and mechanical linkages to control movement and test area
forces
Nominal speed: 1 cycle per second
Forces applied to test area: 20-50 lbs est.

Configuration 1: Direct "Scissors jack" application to maximize force with
minimal UUT travel
Configuration 2: Nominal force for testing energy features, foot rolling to
exercise different conversion modes using simulated artificial foot carrier
Configuration 3: Larger force capability for testing with combined
application samples including current sample of carbon fiber foot element
Configuration 4: Variable speed application to illustrate special cases
application (running?) Possible use of direct drive motor

Scissors Jack sequences:
Lifted leg element has no contact with floor
Initial contact of foot to floor is made, knee joint is bent reducing floor
thrust movement by 0.5 inch
Force is applied to knee joint to create foot thrust force, foot movement is
up to 0.5 inch OR foot element bending takes place
Full foot thrust force is developed
Conclusion: fixture must be adjustable in thrust distance and thrust attack
angle to develop forces required in the foot element under test(suggestion-
use human model in simulation poses) Restricting rollers can be used with
test samples in fixtures!

Austin working on the App that will monitor our device. Notice the LED is turning on and off through a Bluetooth connection he programmed.

Starting fabrication of our tester.

Electrical schematic of the motor wiring.

Thaying making a blog post.

Work Night 11.15.18

Work Night

DATE: November 8th 2018
TIME: 4:45 - 7:00 (2.25 hours)
People Who Attended:
Alex, Seth, Tanner, Avery, Paige, Thomas, Austin

Research Meeting for Prosthetic Limb - Lemelson MIT InvenTeam
Notes submitted by: Alex Magnuson


Today we discussed  a potential part-time software monitor system. The system would only be able to turn on in times when there are enough volts to sufficiently charge the smart puck battery and there are extra volts to turn the software monitoring chip on. When using capacitors it's worth noting that a larger cap will draw more current which in turn decreases the voltage. There is a happy medium between capacity and voltage. We learned about a circuit that will make our generators generate positive voltage in both directions.
We worked with a motor with a geared head that Seth and I did some testing with. We hooked it up to the oscope and with only about a half turn of rotation we could jump up to 10 volts and with a more aggressive spin we could get it up to 60 volts.
Seth and I finished our spring scale testing and have the data logged on a process documentation sheet. We tested the negative to positive voltage converter circuit and had good results with it.
As a team we also decided on what some of our main goals are. They include: when should the computer be turned on? Find out how many volts do we need to trickle charge the battery. When should the computer turn on, read, and then relay information? And most basic goal of getting enough power to battery.

Seth, Thomas and Alex gathering data from gearboxes.

Using an oscope to monitor voltage outputs.

Thomas working on a "puppet" to simulate the motion of the prosthetic limb.

More gearbox testing.

Paige working on public relations.

Taking in a lecture on systems integration.

The team working on fundraising opportunity and software/hardware interface.

Testing gearboxes.

Thomas cutting out the "Puppet" to simulate foot motion.

More testing on gearboxes.

Force Testing the Prosthetic Foot 11.13.18

Force Testing Result 11.13.18

Setting up the force testing system using wood clamps.

Aligning the force plate and calibrating software to conduct the test.

Video of students testing the force it takes the deflect the heel of the prosthetic foot 0-1/2"

Work Night 11.8.18

Work Night
DATE: November 8th 2018
TIME: 4:45 - 7:00 (2.25 hours)
People Who Attended:
Alex, Seth, Tanner, Avery, Paige, Thomas


Research Meeting for Prosthetic Limb - Lemelson MIT InvenTeam
-Discussed a testing device using gears and a self made treadmill to simulate walking
-It was undecided whether our previous design or the new design would work better
-Discussed how to measure energy when running tests
-Could use force plates, piezo or anything that generates feedback when stepped on
-Mr. Foye demonstrated the use of different gear boxes and a very cheap motor attached to a lever to generate power from about a half inch of motion at the axle
-One of the gear boxes was just direct to the motor and still generated about 5 volts with practically no resistance.
-The other was more resistive but still within reason but generated upward of 80 volts
-The use of an expensive motor and gear box could result in very substantial gains in power.
-We also made a small task list to complete

Submitted by: Alex Magnuson
Today Mr. Foye shared his idea on a new testing machine using gears to create a consistent step. In addition, the machine would also use a treadmill to help simulate the motion of walking. It is disputed whether we want to pursue our previous testing idea or the new one. We learned about ways to test our devices and methods to calculate power. We can use force plates or piezo or other measurements methods and use the feedback from those devices to calculate the power that a step makes. In testing the energy production device we can use the resistance of the motor and voltage created by using the formulas and steps below to figure out power produced. The use of two gear boxes with a motor at the output and a lever at the input. The first one had very low lever resistance but a lower output at around 5 volts. The second gearbox was more resistive than the first but generated substantially more voltage at around 80 volts. A google sheet table was made to show how load effected power output based on these demonstrations (Shared with Paige and Mr. J). It was mentioned that the tools used in the demonstration were very cheap and with higher end components we could get much better numbers. We also came up a small task list for us to complete (Below).

How to test for load on lever and generator
-measure terminal to terminal resistance
-Voltage divided by internal resistance + load resistance = current total
  -V/IR (Internal Resistance) +LR (Load Resistance) = I (Current Total)
-Power in watts = Current^2 * Load resistance I^2 * LR (Load Resistance)
-power*time = j
operating capacity = 13.5 Kj
Task List
1) Force deflections in various places on foot
1a) what tests
-single operation
-continual operation
1b) more ideas
-angle adjustments for ankle
Measurements
-force(piezo or force plate)
-deflection
-electrical (Voltage, Current, Power, Efficiency, Etc.)
2)Gear Motor requirements for testing machine
3) Detailing Design
4) Build Tester
5) Measurements

Mr. Foye going through some engineering calculations for testing device.

Thomas, Alex and Seth watching as Mr. Foye illustrates the testing device options.

Tanner uploading waiver forms on the Lemelson-MIT site.

Tanner, Paige and Avery working on the PR Powerpoint.

Students measuring electrical output from gearboxes with an O-scope. Notice how the voltage generated spikes on the scope into the 5 V range with this basic system. The other gear box was much higher into the 30-40 volt range.  

Alex and Thomas working on a lever and generator spreadsheet (and eating pizza).

Notes from our engineering consultant, Mr. Foye:

Session number one introduced the idea of a small DC machine as a generator

this session will present two examples of gear trains connected to small DC machines to allow basic testing

the goal of the idea is to develop basic feasibility of a battery charger for the vacuum pump puck, not necessarily a production design.

One principle of feasibility development is to attempt demonstration using a configuration which suggests a direction for the production design. To aid in this the technology available to be used should be readily available, to allow a basic size and cost assessment

with a demonstrated design configuration, observations may be made about possible refinements in an optimized design. The development of the feasibility model enables the development of basic design parameters, and the demonstration and testing to validate those design parameters as practical.

The majority of the work and then becomes team development of basic ideas using readily available technology, with follow-up testing and evaluation of demonstration prototypes. This avoids some of the problems with the requirement to do a fundamental design, not taking advantage of available technology, and then requiring the fabrication of new or novel components. Using available technology, the only barrier to a testable prototype is the fabrication of the application system, rather than the basic components themselves. Using engineering principles, some extrapolation in performance of the use of optimized components can be projected.

Exploration of geartrain drive with a DC machine

in exploring the operation of a geartrain driven generator, rapid construction of test prototypes which are expected to operate near the projected required performance can be done to explore the trade-offs inherent in those system approaches. A longer geartrain with more gear elements is capable of more variation in speed and torque output, which then can be applied to a broader range of generators that may be available. It may be more feasible to generate higher voltage and lower currents, if that is desired.

On the other hand a smaller geartrain will have a much narrower range of speed and torque, restricting available machines to limited output, which then requires more extrapolation of the generator design to obtain the desired output usable by the electronics.

Using this approach they system demonstration starts to take the shape of working backwards from the load requirement to determine power electronic conversion stages. The next step is extrapolation to the generator and mechanical links to determine the generator stage required performance.

The process then becomes:

0) identify the basic range of system operating parameters that may be acceptable

1) establish basic operating characteristics of the generator

2) establish basic operating characteristics of the geartrain

3) build demonstration generator and geartrain prototypes to explore operating characteristics using data from zero, one, two

4) system and storage suggested by the data from step three

5) evaluate the results of steps three and four; iterate on steps three, four, and five is necessary to arrive at a successful result or meet a deadline

6) adapt a prototype to a demonstration tester for display of the feasible result