Hold about 1.5s above the threshold. That pad goes soft; other pads may take more load.
For each rule: what we do, a real quote that supports it, why that quote means this rule, then the APA citation and link. Quotes that only sit near the topic but don’t force the rule are left out.
What the code does: when H stays high long enough, open the vent on H only (let air out, make H soft).
“with a PP of this magnitude, the module would likely be turned off to offload that region to prevent a foot ulcer. When the module was turned off during the tests, the module instantaneously deformed to 1.5mm… allowed for a maximum reduction of PP of 18–24% directly over the module”
Why R1: When pressure is high, they turn the module off so it squashes more under that spot, and peak pressure drops. So we vent/soften under H. We do not stiffen or inflate under H.
Hemler, S. L., Ntella, S. L., Jeanmonod, K., Köchli, C., Tiwari, B., Civet, Y., Perriard, Y., & Pataky, Z. (2023). Presentation of an intelligent plantar pressure offloading system. Lower Extremity Review. https://lermagazine.com/article/presentation-of-an-intelligent-plantar-pressure-offloading-system (excerpted from Hemler et al., 2023, Frontiers in Endocrinology, https://doi.org/10.3389/fendo.2023.1166513)What the code does: with surround on, slightly fill non-peak pads so load can leave H (rough demo of “spread the load”).
“The overriding principle of all casts is to ‘spread’ the load from a small to a large area, reducing the unit of the load.”
Why R2: Offloading means moving load from a small hard spot onto a larger contact area. So we raise support on other pads while H is soft, not only act on H alone.
The principles and practicalities of offloading diabetic foot ulcers. (2016, November 10). The Diabetic Foot Journal / Diabetes on the Net. https://diabetesonthenet.com/diabetic-foot-journal/the-principles-and-practicalities-of-offloading-diabetic-foot-ulcers/“It’s all about the stress transfer, so what you’re trying to do is unload a certain spot on the foot—generally the met head with a met pad—and transfer it to a more proximal region.”
Why R2: The job is unload site A and move force to other tissue, not just “make the number under A look smaller.” After we soften the peak, we also need support somewhere else.
Gargiulo, G. (2014). Evidence-based use of metatarsal pads (quoting M. Mueller). Lower Extremity Review. https://lermagazine.com/cover_story/evidence-based-use-of-metatarsal-pads“In 1963, an early offloading publication established that providing equal distribution of plantar pressure throughout the sole of the foot was the principal factor in healing trophic ulcerations occurring in a neuropathic population.”
Why R2: The goal is more even pressure across the sole (lower peaks by sharing load). That points at multi-zone redistribution, not single-zone-only action.
Hanft, J. R., Hall, S., & Kapila, S. (2011). A guide to preventative offloading of diabetic foot ulcers. Podiatry Today. https://www.hmpgloballearningnetwork.com/site/podiatry/guide-preventative-offloading-diabetic-foot-ulcersLimit: Papers support transfer / more even pressure. They do not say “inflate every non-peak pad.” That part is our demo shortcut, not a clinic protocol.
What the code does: equalize starts only after the threshold is held. One sample or one gait spike is not enough.
“Diabetic foot ulceration occurring on the plantar aspect is predominately caused by a loss of protective sensation with a combination of excessive or sustained compressive, shear and frictional forces leading to tissue failure.”
Why R3: Damage is linked to too much force over time, not one instant spike. So we use a hold timer before we call a hotspot and move air.
The principles and practicalities of offloading diabetic foot ulcers. (2016, November 10). The Diabetic Foot Journal / Diabetes on the Net. https://diabetesonthenet.com/diabetic-foot-journal/the-principles-and-practicalities-of-offloading-diabetic-foot-ulcers/“Duration: the amount of time any given force is in contact with the foot.” … “clinicians must think in terms of reducing the duration, velocity, magnitude and direction of force or its redistribution.”
Why R3: Duration is called out as its own factor. So “how long above threshold” matters, not only how high the reading is.
The principles and practicalities of offloading diabetic foot ulcers. (2016, November 10). The Diabetic Foot Journal / Diabetes on the Net. https://diabetesonthenet.com/diabetic-foot-journal/the-principles-and-practicalities-of-offloading-diabetic-foot-ulcers/“Repeated loading of high peak plantar pressure during walking has been associated with skin breakdown although there is no definite threshold that predicts ulceration. One must also consider the duration and repetition of pressures.”
Why R3: High peak alone is not the full picture; you also need duration and repetition. So we do not actuate on the first sample.
Hanft, J. R., Hall, S., & Kapila, S. (2011). A guide to preventative offloading of diabetic foot ulcers. Podiatry Today. https://www.hmpgloballearningnetwork.com/site/podiatry/guide-preventative-offloading-diabetic-foot-ulcersLimit: Sources support a hold/duration check. The exact 1.5 s is our demo number, not from a cited threshold study.
What the code does: lock bladder heights. Don’t snap back to flat until Clear or a new press cycle.
“The PP-redistribution process is to be performed consistently while the footwear is being worn.”
Why R4: Redistribution is meant to stay while the shoe is worn, not a one-frame blip that resets every step. So after we move air, we hold that shape.
Hemler, S. L., et al. (2023). Presentation of an intelligent plantar pressure offloading system. Lower Extremity Review. https://lermagazine.com/article/presentation-of-an-intelligent-plantar-pressure-offloading-system“As the individual wears the shoes, the insole will regularly read the PPs and automatically change the contour of the insole”
Why R4: The idea is a shape that stays and updates when pressures change, not a shape thrown away right after one move. So: hold, then re-measure when you press again.
Hemler, S. L., et al. (2023). Presentation of an intelligent plantar pressure offloading system. Lower Extremity Review. https://lermagazine.com/article/presentation-of-an-intelligent-plantar-pressure-offloading-systemCode will not: pump the high-pressure zone.
“The met pad is typically employed to shift the load from the metatarsal head to the shaft of the metatarsal and surrounding tissue, decreasing the pressure at the met head”
Why not: Relief means moving load away from the hard spot onto other tissue. Pumping extra height under the hard spot does the opposite, so we ban inflate-under-H.
Gargiulo, G. (2014). Evidence-based use of metatarsal pads. Lower Extremity Review. https://lermagazine.com/cover_story/evidence-based-use-of-metatarsal-pads“Hsi et al also found that foam rubber met pads led to the greatest pressure reductions when placed just proximal to the peak pressure of the met head, and consider it to be the optimum positioning for pressure relief.”
Why not: Best pad placement is just behind the hard spot on the met head, not under the peak itself. So support under H is the wrong strategy.
Gargiulo, G. (2014). Evidence-based use of metatarsal pads. Lower Extremity Review. https://lermagazine.com/cover_story/evidence-based-use-of-metatarsal-pads“with a PP of this magnitude, the module would likely be turned off to offload that region to prevent a foot ulcer.”
Why not: Under high pressure the module should be off (softer), not on/stiff. Inflating under H flips that polarity.
Hemler, S. L., et al. (2023). Presentation of an intelligent plantar pressure offloading system. Lower Extremity Review. https://lermagazine.com/article/presentation-of-an-intelligent-plantar-pressure-offloading-systemCode will not: soften support pads while leaving the peak hard.
“It is vitally important to remember that whenever force is reduced or removed from one area, it relocates to another. The aim is to reduce injurious forces at an ulcerated site, however, it would be disastrous to create a new lesion by overloading another area.”
Why not: If you drop support under other tissue while H stays hard, force piles onto H (or makes a new sore). The aim is less force at the bad site, not “make all pads the same height by collapsing supports.”
The principles and practicalities of offloading diabetic foot ulcers. (2016, November 10). The Diabetic Foot Journal / Diabetes on the Net. https://diabetesonthenet.com/diabetic-foot-journal/the-principles-and-practicalities-of-offloading-diabetic-foot-ulcers/“Pressure is spread out across the plantar surface of the foot with total contact insoles so not all the pressure focuses on the previous ulceration site.”
Why not: Good geometry keeps load spread so pressure doesn’t pile on the sore. Deflating the rest of the sole focuses contact instead.
Hanft, J. R., Hall, S., & Kapila, S. (2011). A guide to preventative offloading of diabetic foot ulcers. Podiatry Today. https://www.hmpgloballearningnetwork.com/site/podiatry/guide-preventative-offloading-diabetic-foot-ulcersCode will not: fill pads only because they sit next to the peak on a zone map (old neighbor mode).
“I would say that the placement is the most important thing in regard to getting a positive or negative response.”
Why not: What matters is where you put the transfer pad, not “any zone next door on the graph.” Zone IDs next to H are not a placement rule, so neighbor-only fill is out.
Gargiulo, G. (2014). Evidence-based use of metatarsal pads (quoting M. Mueller). Lower Extremity Review. https://lermagazine.com/cover_story/evidence-based-use-of-metatarsal-pads“Hastings et al … found that the ideal placement distance for the most consistent pressure reductions is 6.1 to 10.6 mm proximal to a line identifying the met head.”
Why not: Evidence points to a specific offset just behind the hard spot, not “inflate zone index ±1.” Being next on the graph does not make a pad the right support.
Gargiulo, G. (2014). Evidence-based use of metatarsal pads. Lower Extremity Review. https://lermagazine.com/cover_story/evidence-based-use-of-metatarsal-pads“Windows may be cut into cast devices but a very high-pressure area can occur at the window edges due to the compressing mass of the body and rigidity of the cast material.”
Why not: Local unload with hard edges can make new high-pressure rims. One or two steep pad hills are that kind of harsh shape, so we skip them for broader surround (R2) with soft under H (R1).
The principles and practicalities of offloading diabetic foot ulcers. (2016, November 10). The Diabetic Foot Journal / Diabetes on the Net. https://diabetesonthenet.com/diabetic-foot-journal/the-principles-and-practicalities-of-offloading-diabetic-foot-ulcers/3Ready · Dionne, Jayden & Theresa. Aim: working demo by late September to early October 2026 (target day: 3 Oct 2026). Design, code, and simulator are ready. Next: parts, printing, and real hardware.
| Item | What it means | Pass if… | Due | Status |
|---|---|---|---|---|
| S0 Design & code | Plan, firmware sketch, web monitor, simulator, build notes ready | You can open the monitor and run the sim without hardware | 3 Aug | Done |
| S1 Parts bought | Starter kit on the desk (board, at least 2 FSRs, pump, MOSFET, tubing, wires) | All starter parts on the desk | 22 Aug | To do |
| S2 Bladder holds air | 3D-printed TPU pouch (or first bladder) leak-tested with soapy water | No bubbles; stays firm at least 1 minute after fill | 5 Sep | To do |
| S3 2-zone works | Breadboard: press one zone, correct pump/valve reacts | Works in 9 of 10 tries on the bench | 12 Sep | To do |
| S4 Correct logic | Soft under the hard spot; other pads may firm up. Never pump under the peak. | Anyone watching can see the peak softens, not hardens | 19 Sep | To do |
| S5 Measurable change | Same weight on a zone before and after the system reacts | Sensor reading on that zone drops by about 15% or more | 26 Sep | To do |
| S6 Live screen | Phone or laptop shows the monitor while the prototype runs | Stays connected for a short demo (a few minutes) | 26 Sep | Sim only |
| S7 Demo package | Short video, poster or slides, parts list with cost | Ready for live demo / final presentation | 3 Oct | Final |
| S8 Safety basics | Max inflate time, rest after actuate, pump cutoff | All three on the real build | 3 Oct | In code |
| Task | W1 4–10 Aug |
W2 11–17 |
W3 18–24 |
W4 25–31 |
W5 1–7 Sep |
W6 8–14 |
W7 15–21 |
W8 22–28 |
W9 29–5 Oct |
W10 6–12 |
|---|---|---|---|---|---|---|---|---|---|---|
| 1. Research & design S0 · plan, code, simulator | ||||||||||
| 2. Buy parts S1 · starter kit first | ||||||||||
| 3. Print & leak-test bladders S2 · TPU air pouches | ||||||||||
| 4. 2-zone breadboard S3 · first working loop | ||||||||||
| 5. Full build (more zones + screen) S4 · S6 · ESP32 / phone view | ||||||||||
| 6. Tests with weights S5 · measure before/after | ||||||||||
| 7. Build into insole layers Foam, sensors, tubes, shoe demo | ||||||||||
| 8. Poster, video, report S7 · video, poster, parts list | ||||||||||
| 9. Final demo day S7 + S8 · present the build |
Timeline in weeks. Bars are planned windows, not exact days. “Sim only” on S6 means the computer demo works; the real board and Wi‑Fi screen still need building. Update statuses when a step is done.
3Ready · Dionne, Jayden & Theresa