Comment by Drew on What might cause light vertical banding on LCD?
@Justme The problem follows the MCU. I only have 1 display.
View ArticleComment by Drew on Are there any tricks for measuring high voltages (~1000 V)...
45mW isn't the end of the world, but this is a small battery powered device so I would hope for more like 5mW.
View ArticleComment by Drew on Are there any tricks for measuring high voltages (~1000 V)...
Very thorough, thank you!
View ArticleComment by Drew on Why is my current sensor multiplying voltage by 5000?
The output of U1 cannot exceed V+, so you won't fry your controller regardless. See voltage output on page 8 of the datasheet.
View ArticleComment by Drew on Brushless DC motor stalls at startup
The answer is that you shouldn't do this. The fans will not receive a steady DC voltage, which is what they are designed to work with. Use a step down regulator and put them in parallel. Or buy...
View ArticleComment by Drew on Current driven proportional solenoid EMC
If EMC is a concern, I would consider driving it with a voltage or current source. That should be fairly quiet if you design it well.
View ArticleComment by Drew on Core iron barely boosting field strength
It might help if you draw a diagram of your setup and post your calculations
View ArticleComment by Drew on Wiring multiple photoelectric sensors to RPI 4
Please provide your circuit, and a snipet of code showing how you're reading it.
View ArticleComment by Drew on Can I use clear acrylic spray paint as conformal coating?
That's all well and good, but you should buy a new enclosure. Look on automation direct, they're not that expensive. Throw a couple big desiccant packs in there while you're at at.
View ArticleComment by Drew on Dropping 120 volts AC to 100 volts AC
I don't think so. The drop would depend on how much the equalizer draws. It would be clunky, but you could use a variac.
View ArticleAnswer by Drew for Solid state relay driving an inductive load
A zero-crossing SSR may help somewhat. It switches when the voltage is zero and the current is lower (not zero though due to the lag of current behind voltage for an inductor). I would still include a...
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What is the maximum PLL output frequency in the STM32H7A3?
I'm setting up a hyperram, and I want to run it at 200MHz, with the DHQC setting enabled. The peripheral manual on page 874 says:DHQC must not be set when the prescaler value is 0, as this action leads...
View ArticleAnswer by Drew for 50 watt high-power LED current problem
You need to keep the LED current (and temperature) below its rated values for it to survive.That voltage booster appears to only have 1 pot, so it likely works in constant voltage mode only. Some can...
View ArticleAnswer by Drew for What's a good way to learn microcontrollers without magic?
If you want to control the bare metal at the lowest possible level, start with a low end PIC MCU and write your code in assembly. The learning curve for this actually isn't too bad, since the...
View ArticleAnswer by Drew for Connecting home elliptical trainer to TV power
I would throw an arduino in there to add a time delay between the elliptical stopping and the TV power shutting off. The arduino will require some power source like a wall wart.I would also recommend...
View ArticleAnswer by Drew for Why do we need multiple capacitors in parallel instead of...
One reason you might use multiple caps is to reduce the number of unique components in the design. Every unique component must be sourced, may go out of stock, requires a reel in the pick and place...
View ArticleAnswer by Drew for Do I need to connect a resistor at the output of an...
Do I need to connect a resistor at the output of Isolated DC-DC converter?Simple answer, yes. You have a digital load with out a published minimum current draw. If you ignore this, you're just asking...
View ArticleWhat is the best way to mitigate the spark when a PCB is connected to power?
I'm designing a moderately powerful motor controller (integrated into a product). The board runs on 24V and has a 100uF electrolytic input cap, as well as 2 10uF ceramics near the switcher.Whenever I...
View ArticleAnswer by Drew for Can I use 2 modes of I2C operation together in 1 code? For...
In i2c the master controls both the write and read operations. The slave cannot send data unsolicited. The master provides the read frame and the slave adds the data to it.Note that a read operation...
View ArticleWhat is the best practice when replacing a ribbon-cable ferrite clamp with...
I'm working on EMC testing a product. We have an internal 30 cm ribbon between 2 boards. One has a MCU and LCD, and the other MOSFETs and a 3 A switching regulator.We determined that a lot of RF is...
View ArticleAnswer by Drew for Am I exceeding maximum limits for this plug?
From a professional perspective: It says no more than 16V, so that's the limit. Exceed it and the component may fail in unexpected ways.But.. practically speaking, that's an absurdly low voltage limit...
View ArticleAnswer by Drew for What tool do I need for measuring DC power consumption of...
It should be pointed out that this is actually quite difficult to do accurately, even for professionals. Modern devices often draw huge bursts of current, followed by long periods of almost nothing....
View ArticleAnswer by Drew for Is it possible to drive a 12 VDC motor with an XL6009?
I think you've got an A/B fallacy here. The first question you need to ask is "where should my power come from". There are tons of 12V battery and mains power options, so I don't see any reason you...
View ArticleAnswer by Drew for How to filter a noisy PWM signal without affecting rise...
You should be able to filter out the high frequency component fairly easily, since it's an order of magnitude higher than your signal of interest.Your signal is 88Hz, maybe up a couple hundred if you...
View ArticleAnswer by Drew for How are simple functions done in commercial products?
Given the current state of technology, an arduino is about the right "power level" to turn leds on and off.The price of a MCU with the capability of an arduino uno is quite cheap, probably 0.1-0.5 USD...
View ArticleAnswer by Drew for Temperature control with Peltier device and temperature...
You need to intelligently switch between heating and cooling.As rdtsc said, you can run them both simultaneously. But you should know that if you do this, you need a very good tune, as the loop can...
View ArticleAnswer by Drew for jpeg images in STM32 internal flash
Use RLE encoding. It's lossless, very simple, and in my experience, will reduce the size of most images by half or more.Reduce the color depth to 8 bits. If you use good software to downsample, it's...
View ArticleAnswer by Drew for How do I simultaneously distribute a GPIO 3.3V logic...
You need to rethink your circuit. The pico should be supplying the logic signal, but not the power. Use a transistor, or perhaps a buffer chip. And draw power from a separate source.If you need 1.65V,...
View ArticleAnswer by Drew for Communication between two microcontrollers with...
There is no problem with doing that. Simply pass the ground and datalines between the devices.The only complication is if BOTH of the devices are connected to ground by separate cables. This creates a...
View ArticleAnswer by Drew for Advantages to a negative power supply rather than ground?
One advantage of having symmetrical supplies is that there are 3 rails instead of 2. With 1 in the middle of the other 2. +15V, 0V, -15V for example, vs 30V, 0V. That's not just a shift. There's...
View ArticleWhy does this LCD Bias Driver Have a Fault Mode?
I have a product that uses a TPS65150 LCD bias driver. I recently had an issue with a batch of boards, where this driver would go into fault mode (low on FDLY pin).The fault mode is triggered on a time...
View ArticleAnswer by Drew for Why might PWM cause a whine sound in a DC motor?
It's quite simple actually. The ardino PWM output is at an audible frequency. Despite all the inertia, the coils in the fan are able to translate some of that pulsing into actual air movement eg....
View ArticleAnswer by Drew for Thyristor blowing up in a coilgun
If one of the SCRs were to fire somehow while those charging switches were closed, the coil and SCR would effectively discharge the capacitance of ALL the capacitors. 6x more than normal. That could...
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Answer by Drew for What's the difference in loading outcome with a 42 vs 48 V...
Your math about the capacity is incorrect."48V" is not enough to know exactly how many cells your pack has, but it is likely 13. It could also be 12 depending on how sleazy the marketing people are.The...
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Answer by Drew for How can I make a continuity check for a model rocket igniter?
That circuit will not work. One simplification you can make when trying to understand circuits is to assume that power supply rails are fixed voltages. That's reasonable in your case. Notice that the...
View ArticleComment by Drew on Connecting sensor and avoiding ground loop
If this is temporary, you can just run your laptop on battery power.
View ArticleAnswer by Drew for What features to look for when buying a microscope?
Presumably you have tried a microscope at university or work or something. If you like it, get that exact one. If you can't afford it, look at the specs and try to find a comparable but cheaper model....
View ArticleAnswer by Drew for Driving a power MOSFET successfully
I believe you've got it right. 24V is fairly close to the maximum mosfet gate voltage of 30. I might go down to 20.Notice that you will be connecting the low side of your bridge rectifier to gnd. You...
View ArticleComment by Drew on Motor and Controller to spin Camera Array
The ultimate solution will likely be a large, low kv brusheless motor. Probably with a belt drive gear reduction. Driving it as a servo will be difficult. Look at the VESC project. There is also a...
View ArticleComment by Drew on how does the shape of a busbar affect current carrying...
I agree with TQQQ. The maximum current carrying capability of a conductor is limited by the maximum temperature or voltage drop you can tolerate. With a fixed cross section, greater surface area will...
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