Search found 76 matches

by e3s
Oct 04 2019 8:28am
Forum: Motor Technology
Topic: opensource 3d printable electronic shifting?
Replies: 39
Views: 1133

Re: opensource 3d printable electronic shifting?

For the stepper motor driver I suggest drv8825 it's cheap, 80 cents.
by e3s
Oct 03 2019 5:41pm
Forum: Motor Technology
Topic: opensource 3d printable electronic shifting?
Replies: 39
Views: 1133

Re: opensource 3d printable electronic shifting?

Good idea. For now I'm looking for buying the joint and the thrust bearing, it could be useful to buy different stepper motor to verify the limit of the torque required. This varies also from the friction of the shaft. The friction is not also the same. Example bronze threaded rod has lower frictio,...
by e3s
Sep 18 2019 6:01am
Forum: Motor Technology
Topic: opensource 3d printable electronic shifting?
Replies: 39
Views: 1133

Re: opensource 3d printable electronic shifting?

not the full travel but only to change a gear (or also two gears,), pull 5 mm of the cable to change the gear with a sram or the half for shimano. It is sufficient to see the weight to pull from the second to the first gear. It's the hardest to pull. Obviously with the chain not without it. my proje...
by e3s
Sep 17 2019 3:54pm
Forum: Motor Technology
Topic: opensource 3d printable electronic shifting?
Replies: 39
Views: 1133

Re: opensource 3d printable electronic shifting?

The problem is this: to change the gear in a certain amount of time there's a need to have a fixed power. If you have a motor with 1000rpm with a gear 10:1 that changes the gear in a second, it will consume the same power of a motor with 100rpm and changes. The gear in a second. So there are already...
by e3s
Sep 17 2019 1:29am
Forum: Motor Technology
Topic: opensource 3d printable electronic shifting?
Replies: 39
Views: 1133

Re: opensource 3d printable electronic shifting?

For now I'm searching a stepper motor that has a constant torque curve, not less than 8 N.cm
Nema8 is a bad choice because it has 4 N.cm. Too low. I'm asking if someone has a balance to measure how many kg are needed to change the gear pulling the cable... I apologized 5 kg but I'm not sure.
by e3s
Sep 09 2019 5:57pm
Forum: Motor Technology
Topic: opensource 3d printable electronic shifting?
Replies: 39
Views: 1133

Re: opensource 3d printable electronic shifting?

I practically thought of two projects: a linear servo as we have already seen or a motor with a screw that turns a round gear and you can also print this in 3d. It's more compact but fragile. If you think about the compactness you have to say that there are also disadvantages. I would prefer a long ...
by e3s
Sep 06 2019 3:29pm
Forum: Motor Technology
Topic: opensource 3d printable electronic shifting?
Replies: 39
Views: 1133

Re: opensource 3d printable electronic shifting?

I'm curious to see a stepper motor directly in a sram derailleur
Anyway a nema stepper motor has enough torque. I read that some linear slide has only a force of 500gr at 360rpm. Maybe is not enough
by e3s
Sep 06 2019 7:01am
Forum: Motor Technology
Topic: opensource 3d printable electronic shifting?
Replies: 39
Views: 1133

Re: opensource 3d printable electronic shifting?

If you search stepper motor slider you find something cheap and almost ready to use
by e3s
Sep 05 2019 8:15pm
Forum: Motor Technology
Topic: opensource 3d printable electronic shifting?
Replies: 39
Views: 1133

Re: opensource 3d printable electronic shifting?

Take in consideration that sram pulls more cable, shimano less. Minimum 2 cm maximum 5cm depends from the number of the gears and if it's a shimano or sram derailleur. Or a less known mark.
by e3s
Sep 05 2019 7:46pm
Forum: Motor Technology
Topic: Bafang SW102 Bluetooth LCD - OpenSource firmware and mobile app
Replies: 303
Views: 19499

Re: Bafang SW102 Bluetooth LCD - OpenSource firmware and mobile app

I would like to make a standalone Bluetooth terrain inclination sensor, so the SW102 could automatically increase/decrease the assistant level based on the terrain inclination -- more assist on hills and less on descends. https://i.postimg.cc/7ZpWS5h4/sku-449109-1-670x.jpg inclination sensor in a f...
by e3s
Sep 05 2019 5:35pm
Forum: Motor Technology
Topic: opensource 3d printable electronic shifting?
Replies: 39
Views: 1133

Re: opensource 3d printable electronic shifting?

I see this calculator: https://daycounter.com/Calculators/Lead-Screw-Force-Torque-Calculator.phtml. maybe it's ok that servo. I think that the for safety reason is better to let the original shifter and the cable and put between the derailleur and the shifter a linear servo. cutting a piece of cable...
by e3s
Sep 05 2019 4:33pm
Forum: Motor Technology
Topic: Bafang SW102 Bluetooth LCD - OpenSource firmware and mobile app
Replies: 303
Views: 19499

Re: Bafang SW102 Bluetooth LCD - OpenSource firmware and mobile app

Open source e-shifter is not a problem, I saw many times ago some projects with arduino.
by e3s
Sep 05 2019 10:21am
Forum: Motor Technology
Topic: Bafang SW102 Bluetooth LCD - OpenSource firmware and mobile app
Replies: 303
Views: 19499

Re: Bafang SW102 Bluetooth LCD - OpenSource firmware and mobile app

I like the original controller but if there's a better alternative...
by e3s
Sep 05 2019 7:47am
Forum: Motor Technology
Topic: Bafang SW102 Bluetooth LCD - OpenSource firmware and mobile app
Replies: 303
Views: 19499

Re: Bafang SW102 Bluetooth LCD - OpenSource firmware and mobile app

From a bit of time I'm thinking to integrate the mid drive with arduino, adding some sensors. Practically riding with two screens, one with all info about the motor. Now I haven't so much time to begin the project but I was thinking if you are interested to connect arduino with sw102 lcd. There are ...
by e3s
Aug 26 2019 7:38pm
Forum: Motor Technology
Topic: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor
Replies: 3892
Views: 194341

Re: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor

Ok. Understood. If the relation between human power and motor power is always the same, there are some condition that is difficult to maintain only a level.
by e3s
Aug 26 2019 7:07pm
Forum: Motor Technology
Topic: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor
Replies: 3892
Views: 194341

Re: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor

Why the power assist curve goes up? The rpm is more multiplied in the formula? One time it's reached the cruise rpm torque assist isn't necessary. I have this style of ride: I need the assist on the climbs and to restart on them, to help me to have a higher cruise speed also on a flat road. At low s...
by e3s
Aug 26 2019 4:14pm
Forum: Motor Technology
Topic: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor
Replies: 3892
Views: 194341

Re: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor

@.7.2 kmh in a 26" it passes 1 time per second @ 21.6kmh the speed is updated every 0.33 seconds Someone has a square pedal and doesn't use the femoral biceps so there are more peaks of assist in the torque mode with low rpm. I think that power assist in this condition is better Each one has their o...
by e3s
Aug 26 2019 3:03pm
Forum: Motor Technology
Topic: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor
Replies: 3892
Views: 194341

Re: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor

I explain my point of view with some examples and numbers. Torque assist is ok if you use the full power. You can reach the desired speed without problem. And if I use a partial assist? If I want to push 10kg @ 60rpm, are more or less 90w and 1.5nm nearly. I need another 1.5nm. I want to go at 30kmh...
by e3s
Aug 26 2019 8:12am
Forum: Motor Technology
Topic: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor
Replies: 3892
Views: 194341

Re: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor

With torque assist you'll never can go outside the saddle if the assist is too much. Many people has this need. You don't feel anymore that the gradient changes, so if you have the highest gear the motor helps you with the maximum power, pedalling is not natural anymore, you don't feel the road. Tak...
by e3s
Aug 25 2019 4:54pm
Forum: Motor Technology
Topic: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor
Replies: 3892
Views: 194341

Re: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor

For me it's better to have more assist climbing and less in the flat road. Nm*rpm*x +speed*k with k negative. It Can be positive. The power is related to the speed so having the speed in the formula is important. Power=2/3 speed^2. To maintain higher speed you need higher motor power, not higher hum...
by e3s
Aug 25 2019 12:22pm
Forum: Motor Technology
Topic: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor
Replies: 3892
Views: 194341

Re: TSDZ2 mid drive -- Flexible OpenSource firmware for TongSheng TSDZ2 mid drive motor

the best way for us to keep our pace of heart rate / workout with the different gears, is to use human power mode and not the torque mode. Yes, right. About the speed in the formula consider that everyone has different gear ratio in each bike. Example a road bike has high gear ratio, mtb bike less....