pointhi / highpower-mechaduino Goto Github PK
View Code? Open in Web Editor NEWMechaduino derivative which drives up to 10A, drawn using KiCad
Mechaduino derivative which drives up to 10A, drawn using KiCad
Maybe it would be beater to change the switch part, so the MOSFET Q1 should be triggered by the USB and not the VDD. I think it would be beater this way because the USB voltage is constant, +5V, and VDD is not, it can be from 12V to 50V, and the gate current would not be the same. See the reference picture:
Regarding enhancements mentioned in the #9 issue, possible option for magnetic encoder is TLV493D which is ~ 1 EUR. There is even a small dev kit for it TLV493D-A1B6 2 GO KIT
I think a resistor with 4-wire-connection should be used for the shunt resistors R16 and R19. Otherwise the load current flowing throw the groundplane could lead to a wrong current feedback due to the parasitic resistance and inductance.
The connection on the drain side is already (almost) correct, but not so on the ground plane.
The collector of the bootstrap diode D5 should be connected to the BOOST pin an not to the SW pin! See the example circuit on page 2 in the datasheet.
Also I think that the output diode D2 should be directly in series with the induction L4. Otherwise the output voltage could drop due to a transient load current. This could also cause stability problems of the voltage regulator.
It would be great if you could also export the schematic as PDF so it is readable online.
According to the datasheet (page 9, bottom) the pins VDD and VDD3V3 should be connected to 3.3V.
C2=1uF can be omitted in this case.
The text saying "I_MAX=14"next to the voltage dividers for VREF (R7-R10) is wrong. Instead it is 11.6A.
U2 = U1R2/(R1+R2) != U1R2/R1
;)
Also I think that the cutoff frequency of the low pass should be a bit higher. With R9, R10=1k and C7, C8=100n the cutoff frequency is ~1.5 kHz.
For a 200 steps/rev motor turning with 2000 RPM (which is not too unrealistic I think) the step frequency (in our case: sine frequency) would be 6667 Hz. I would suggest to set C7 and C8 to 10nF instead of 100nF.
The current component price range is about 50-60€ per board (when buying for 10 pbc's). Not problematic for the prototype board, but we should optimize it.
This is a list of the most expensive parts of the board (based on the discounts you get when you buy for about 10 boards):
Component | price per board | description |
---|---|---|
AS5047D | 8,19€ | encoder |
IPD079N06L3 | 5,90€ | motor driver mosfets |
ATSAMD21G18A | 4,78€ | controller |
A4955GLPTR | 2,84€ | motor controller |
RB162MM-60CT | 2,11€ | schottky diodes |
744773122 | 1,96€ | inductor for step down |
10UF POLY ELCO | 1,83€ | elco for step down (very low esr) |
TERM BLOCK 4POS | 1,67€ | step down connector |
MCP16331T | 1,26€ | step down regulator |
those few (main) components sum up to about 30,54€ per board.
On the programming header P1 the pin 7 is connected to the ground, and in the Arduino zero schematic it is not. I know this is not a big deal, but maybe (in some parallel universe) it could bother the programator when connected.
Based on the 4EUR cost, RPi zero may be a very good choice: https://www.raspberrypi.org/products/pi-zero/ please consider that.
The free wheeling diodes D6-D9 and D10-D13 are schottky diodes so the appropriate symbol should be used.
Also the lower diodes should be connected to the MOSFET-drains instead of GND if possible.
I believe 6A current rating at 48V is completely sufficient for most applications the board would be used with NEMA 23 motors.
I started to design a housing/mounting for the HighPower-Mechaduino on a NEMA24 stepper motor and discovered that the mounting holes in the PCB are made for M4 only while they are for M5 in the motor. See this screenshot:
(The CAD model is based on measurements form an actual motor.)
See also this datasheet of a NEMA 23 motor:
http://www.omc-stepperonline.com/download/pdf/23HS16-0884S.pdf
I think it would be good to change mounting holes in the pcb to fit to M5 screws (a diameter of 5.2mm should be sufficient)
There might be some NEMA23/24 motors where the mounting holes are actually M4, but it is easier to fit an M4 screw into an M5 hole than the other way round. ;)
Hi,
Tried to find any contact info to send you a private message, but couldn't find any thus I'm writing this post.
Have you managed to test current layout of the board? I'm in need of such controller and just wondered if it's working or are there any serious issues that you're aware of?
Let me know if I can help in further development.
Cheers,
Maciej
The diode D1 is not recommended for new design, maybe it would be best to change it. They will probably stop producing it in near future. See the manufacturer link: RB160M-60
A declarative, efficient, and flexible JavaScript library for building user interfaces.
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
An Open Source Machine Learning Framework for Everyone
The Web framework for perfectionists with deadlines.
A PHP framework for web artisans
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
Some thing interesting about web. New door for the world.
A server is a program made to process requests and deliver data to clients.
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
Some thing interesting about visualization, use data art
Some thing interesting about game, make everyone happy.
We are working to build community through open source technology. NB: members must have two-factor auth.
Open source projects and samples from Microsoft.
Google ❤️ Open Source for everyone.
Alibaba Open Source for everyone
Data-Driven Documents codes.
China tencent open source team.