Timeline for Powering microcontroller with a capacitor
Current License: CC BY-SA 4.0
23 events
| when toggle format | what | by | license | comment | |
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| Jan 6, 2021 at 19:02 | comment | added | Francesco M | @BruceAbbott yes that is definetly a possibility. The MCU could run for some time on low power mode until the cap is fully charged. | |
| Jan 6, 2021 at 18:58 | comment | added | Francesco M | @DKNguyen thanks for the answer. Thas is a really interesting solution that I might try out. | |
| Jan 6, 2021 at 18:51 | comment | added | Francesco M | @user4574 yes the 40mA are for the BLE data tranmission and the MCU. The machine is quite large and using this microcontroller simplifies other parts of the project such as data acquisition and compatibility with the software I am currently using | |
| Jan 6, 2021 at 18:08 | comment | added | Bruce Abbott | "except the first time it goes around the MCU has to boot and it requires 0.1 A for about 1 s." - Can you position the contacts to fully charge the capacitor before the part starts moving? Alternatively, can the MCU be held in a low power mode or disconnected until the capacitor has had time to get an initial charge? | |
| Jan 6, 2021 at 18:00 | history | tweeted | twitter.com/StackElectronix/status/1346879209772355587 | ||
| Jan 6, 2021 at 17:06 | answer | added | Spehro 'speff' Pefhany | timeline score: 1 | |
| Jan 6, 2021 at 16:46 | comment | added | DKNguyen | Depending how long contact is made for, you may want significantly larger caps (>5x) on the fixed brushed which are charged up and ready so that you can immediately discharge into the super cap on your moving brush without having their own voltage dragged down by the cap on the moving brush. Otherwise your stationary supply may not react quickly enough and get bogged down, but not so big that your stationary supply can't handle all the output capacitance (or you need to have a series resistor so the stationary supply gracefully charge up and top off the caps on the fixed brush). | |
| Jan 6, 2021 at 16:46 | comment | added | user4574 | @DKNguyen That's a good possibility, but unless this machine is really huge, one would think that here is probably a lower power radio given the short transmit distance. | |
| Jan 6, 2021 at 16:42 | comment | added | DKNguyen | @user4574 I assume the radio. | |
| Jan 6, 2021 at 16:42 | comment | added | user4574 | What is using the 40mA the hall sensor or the MCU? 40mA seems a little high given the functionality you are describing. | |
| Jan 6, 2021 at 16:37 | history | edited | JRE | CC BY-SA 4.0 |
added 5 characters in body; edited title
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| Jan 6, 2021 at 16:33 | comment | added | DKNguyen | Smaller caps won't smooth anything by definition. How do you plan on smoothing out the voltage of a big cap with small caps? You can't. At some point, the DC-DC converter brick and all the enormous capacitors you throw into the spinning wheel, plus the brushes, are going to be heavier and more complicated than just a battery. It's easy enough to try though at your slow speeds. The most complicated part is mounting the brushes, but leave room for a battery in case it doesn't work out. | |
| Jan 6, 2021 at 16:31 | history | edited | Francesco M | CC BY-SA 4.0 |
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| Jan 6, 2021 at 16:29 | comment | added | Francesco M | I know but the whole point was to avoid using a battery. Maybe I could use some smaller capacitors before the DC-DC converter to smooth the Voltage? | |
| Jan 6, 2021 at 16:14 | comment | added | user263983 | It is not best idea because capacitor voltage going down due to discharge. You will get pulsation . Smooth it may be complicated. Some battery simpler solution. | |
| Jan 6, 2021 at 15:59 | comment | added | Francesco M | Rather than RPM the brushes would pass by at around 1.5 m/s and yes I am using Bluetooth LE to transmit the data. | |
| Jan 6, 2021 at 15:47 | comment | added | DKNguyen | What is the RPM? 7.5RPM? Because brushes make sparks which could interfere with your radio (which I assume is what you are using to transmit data). Powering RF from a noisy, unstable supply and transmitting when sparks are present might be asking for trouble. | |
| Jan 6, 2021 at 15:47 | comment | added | Francesco M | The MCU evaluates and sends data from a Hall Sensor, which is used to mesure the distance of a magnet. So I would rather not have electomagnetical interference and therefore use "touching" parts. | |
| Jan 6, 2021 at 15:39 | comment | added | DKNguyen | Can you use a transforming action or induction. You can't mount brushes around the wheel and wire them back? (which is what a slipring would be). Also consider a battery. | |
| Jan 6, 2021 at 15:29 | comment | added | Francesco M | The MCU unit moves in a circle but not on itself. As if it was mounted on the edge of a big wheel that spins and the MCU goes by the charging point only one time per revolution of the wheel | |
| Jan 6, 2021 at 15:22 | comment | added | Parker | What about a slip ring? en.wikipedia.org/wiki/…. | |
| Jan 6, 2021 at 15:21 | review | First posts | |||
| Jan 7, 2021 at 0:33 | |||||
| Jan 6, 2021 at 15:17 | history | asked | Francesco M | CC BY-SA 4.0 |