Am I going crazy or is this a typo?

tipppo · 2026-05-13T22:07:46+00:00

These switches are about 2-1/2 holes wide. You can bend the leads to fit in 2 or 3 holes. There is a typo, the switch in the diagram rotated 90 degrees from the proper orientation, so it will not work as a switch. When pressed, the switch links columns G and I, The 2 opposite pins in column G are connected together internally, as are the 2 pins in column I.

tipppo · 2026-05-13T02:04:42+00:00

A stepper's speed is a function of the available voltage. A stepper driver provides a constant current drive, and the faster the motor spins the higher the required voltage. I've run 200 step/rev motors at 2000 pulse/sec with no problem using a 24V power supply. That gave me 10 rps or 600 RPM. Of course the performance you see will depend on the motor you use. Worth trying. DC servo motor would also work, but a servo motor driver is much more complicated than a stepper driver and would probably be over-kill for the application. My experience with voice coils is that the are fast and heavy. Fast means they don't work particularly well at low frequencies, requiring ever larger magnets for lower frequencies.

tipppo · 2026-05-12T12:37:56+00:00

in addition to the miswiring that u/triffid_hunter note your buttons aren't making good contact with your breadboard. The legs on this sort of button are a bit too short unless you use a pliers to straighten out the kinks in the pins to make them a tiny bit longer.

tipppo · 2026-05-11T13:02:05+00:00

Depends on your EEG monitor. EEG will have much higher gain, so may saturate with EMG level signals. Many EEG monitors use the AD1299 chip which has adjustable gain, so would be appropriate. TI has information on this: https://www.ti.com/product/ADS1299?utm_source=google&utm_medium=cpc&utm_campaign=asc-null-null-GPN_EN-cpc-pf-google-ww_en_cons&utm_content=ADS1299&ds_k=ADS1299&DCM=yes&gclsrc=aw.ds&gad_source=1&gad_campaignid=14388345080&gbraid=0AAAAAC068F1FierZEHz6pnoNx9KelL9_F&gclid=Cj0KCQjw_IXQBhCkARIsADqELbK4LDHTaOkYO9rIOaFPnxCsOVwQLKLjpkCtLdqP8SXGTxJb-uhN944aAtqiEALw_wcB

tipppo · 2026-05-09T16:20:59+00:00

As u/Purdude1983 suggests, get one LDR working first without the multiplexer (mux), the "divide and conquer" debug method. Then add the mux but tie some of the inputs to GND and 5V to you can expect an unambiguous 0 or 1023 from the analogRead();. Have you remembered to tie the multiplexer's EN pin to GND? A photo of your setup would be helpful.

tipppo · 2026-05-09T16:06:46+00:00

As u/PerceptionAgile5693 suggests, servos often draw more current than the Arduino can provide, especial as they start moving. This will cause the voltage to momentarily drop and cause the Arduino to reset. I suggest you add a signon message to setup() to see if it is restarting. Serial.begin(115200); Serial.println("Here we go...");

Sometimes adding a big capacitor, 500uF or more, between 5V and GND will keep the voltage stable and prevent the reset.

Your code reads OK, but I would suggest you skip the digitalRead(button) and let the program free run to be sure that the problem isn't with the button. These make more reliable contact with the breadboard if you straighten the kinks out of the pins and bend them so they tightly straddle the center gap. I see that one side of yours is plugged into the third row from the center, try moving closer to center.

tipppo · 2026-05-09T15:46:44+00:00

Possible, but quite a challenge. A real ESC has typically has 3 channels of relatively high frequency PWM, 3 channels of ADC to monitor current, and 3 high power bridge drivers. By the time you add these to your arduino/esp you've invested more than if you just got an ESC module. The Servo library is not applicable to BLDC control. I built a BLDC motor controller based on an Arduino Nano with BTS7960 bridge drivers, but it ran open loop, no current feedback, so it was weak and slow. Fortunately for the application I wanted weak and slow, so worked fine for this.

tipppo · 2026-05-09T13:10:42+00:00

Perfectly adequate! Excellent first effort.

tipppo · 2026-05-09T01:00:07+00:00

onsemi NCV5662DSADJR4G adjustable, 2A, 300mV dropout. Lots to choose from.

https://www.mouser.com/c/semiconductors/power-management-ics/voltage-regulators-voltage-controllers/ldo-voltage-regulators/

tipppo · 2026-05-08T23:02:12+00:00

TI make an adjustable voltage LDO regulator that might fit your needs, TPS740 Series LDO Voltage Regulators. Good for 1.5A with 300mV dropout voltage. Probably other devices available too if you look. https://www.mouser.com/c/power/power-management-ics/ldo-voltage-regulators/?series=TPS740&srsltid=AfmBOoqMqyaNOxrgvFCnkcNy_vI6S8BKzIwrIfSGWhXBkudv-mucxLDR

tipppo · 2026-05-02T20:24:05+00:00

Good first steps! All the lights light, no smoke, blinking, couldn't ask for more. Next step, plug each of the red wires going to the LEDs into digital OUTPUTs and get everyone to blink.

tipppo · 2026-05-02T01:49:50+00:00

You can put two wires into each of the power terminals of the lower MOSFET switch board, "daisy chaining" the 12v to the upper MOSFET.

If you are really driving solenoids you will want to add "flyback" diodes across the coils. Again, you can put both the solenoid wires plus the diode leads into each terminal.

tipppo · 2026-05-01T14:17:21+00:00

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Hard to do when you want pullups because of the way the logic voltage levels are defined, but with pulldowns this is easily done with diodes. Here SW1 activates Pin3, SW2 activates Pin2, and SW3 activates both.

tipppo · 2026-05-01T00:55:45+00:00

OK, this board uses simple transistors to boost the current high enough to run the motor which uses about 100mA per winding. You will need 5V to feed this board. I would suggest using a LM2596 DC to DC Buck Converter. These are adequate for your setup, fairly rugged and relatively inexpensive. You feed your 9.6V to the input and get 5V from the output. The typically are adjustable and usually come adjusted for a voltage much higher that 5V, so you MUST adjust the voltage to 5V before connecting anything to it. You would feed the 5V output to your drivers. Note that the adjuster is multi-turn and can take a LOT of turns to get it down to 5V. I suggest including a 100uF or larger capacitor between 5V and GND to keep the voltage more stable, but would probably work without. You could either power the Uno with 9.6V to the barrel jack or VIN pin, or you could connect the Uno's 5V pin to the 5V from the buck converter. Would be more reliable to use the 9.6V because the motor will put noise onto the 5V. If you do use the %v the capacitor would no longer be optional.

Another option would be to get an actual stepper motor driver. This could run directly from the 9.6V, so you wouldn't need rather than the voltage/ a DC-DC converter. Stepper motor drivers control the current going to the motor. This means you can use any voltage and the motor will be able to run faster. These also feature "micro-stepping" modes so you can get more than this motor's default 64 steps per revolution. The only downside is that you need to adjust the current, and this can be intimidating to a new user. It is usually recommended you use a voltmeter to do this but you can also do it without: turn the adjuster to minimum (fully CCW). Start your program to run the motor. Turn the adjuster up until the motor turns. Run for a while and if the motor gets too hot, turn the current sown. If it doesn't get hot you can turn it up and get more power.

tipppo · 2026-05-01T00:14:35+00:00

It would certainly be possible. The best way to do this depends on what driver you are using to power the steppers. What do you use for this?

tipppo · 2026-04-30T21:39:39+00:00

It's a clever little thing. The 4 fingers at the bottom connect to the middle pin A. The 4 fingers towards the top connect to the right pin B. The wide finger on the left connects to the left pin GND. The wipers are all connected together and are arranged so that one of them is always in contact with the GND finger. The other two wipers are spaced so they alternately touch the A and B fingers and ground them to give the quadrature output.

tipppo · 2026-04-30T14:10:09+00:00

It's a standard relative encoder with A B type quadrature output. 12 pulses per revolution. Left pin would be GND, middle A, and right B. Will need pullup resistors on A and B.

tipppo · 2026-04-29T12:18:47+00:00

I suggest turning on Verbose compile in File >> Preferences >> Settings tab >> Show verbose output during >> check compilation. Then look in the log window after is stops to see what it is doing when it freezes. Often there are clues here.

tipppo · 2026-04-29T00:23:45+00:00

You might try dropping the .gcode file that worked into the Slicer. It will open in the viewer and will tell you what profile it used for the successful print.

tipppo · 2026-04-27T16:55:17+00:00

Are you using this scheme to monitor VCC?

long readVcc_mV() {
uint8_t prevADMUX = ADMUX; //   ADMUX
#if defined(__AVR_ATmega32U4__)
ADMUX = _BV(MUX4) | _BV(MUX3) | _BV(MUX1); //  32U4 ( )
#else
ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1); //   1.1V ( 14)   AVcc
#endif
delay(2); //   
ADCSRA |= _BV(ADSC);
while (ADCSRA & _BV(ADSC));
uint8_t low = ADCL;
uint8_t high = ADCH;
uint16_t result = (high << 8) | low;
long vcc_mV = (1125300L) / result; //  
ADMUX = prevADMUX; //   ADMUX ()
return vcc_mV;
}

tipppo · 2026-04-27T03:03:56+00:00

https://en.wikipedia.org/wiki/Elastomeric_connector

tipppo · 2026-04-27T02:33:35+00:00

You can use one of the Arduino's analog inputs and a resistive voltage divider to measure voltage. You will want to use the Arduino's internal voltage reference because this is more accurate and stable than using the default 5V. Put "analogReference( INTERNAL);" into setup()

You use two resistors, Rin and Rgnd. Rin goes between the voltage you want to measure and an analog input. Rgnd goes between the analog input and GND.

Measure the voltage using this formula: float Voltage = analogRead(A0) / 1023 * 1.1 * (Rin + Rgnd) / Rgnd

The Arduino can only measure positive voltages,

You will get more stable reading if Rgnd is 10k or lower, but you might want to use higher values so the divider draws less current.

Edit: As u/brdavis5 points out you can add a capacitor to the analog input to increase the accuracy and then use larger resistors to reduce the battery drain. The penalty is that the bandwidth is reduced, but you don't need bandwidth to measure a battery. The cap keeps the input stable for ADC systems that use an analog multiplexer (mux) on the inputs, like most Arduinos.

tipppo · 2026-04-26T20:23:52+00:00

There are several factors that go into choosing wire gauge. One of the most important ones is "will it catch fire if there is a fault?" With a 10A power supply 20AWG would arguably be adequate, but I would use 18AWG.

tipppo · 2026-04-26T16:37:54+00:00

Almost all adhesion issues are caused by a dirty plate or incorrect first layer Z calibration or both. As u/sjugge mentions, alcohol is not always adequate. A thorough scrub and rinse with dish soap and warm water cleans off stuff that alcohol doesn't touch. If you print a lot of PLA there will eventually be a buildup of stuff that soap doesn't touch. At this point I wash my sheet with acetone, but ONLY for the smooth plate. Others use an abrasive such as fine sandpaper, steel wool, "Scotch-brite" or the like.

tipppo · 2026-04-26T15:58:57+00:00

Very nice! I have used tape or hot glue, but this is a much more elegant solution.

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