Electronics Forum (Circuits, Projects and Microcontrollers) An electronics forum to talk all about circuits and projects. Fri, 18 Jan 2019 17:34:08 +0000 Fri, 18 Jan 2019 17:34:08 +0000 Electronics Forum (Circuits, Projects and Microcontrollers) http://www.electro-tech-online.com/ High Switching Speed, High GPIO Count dev board. Fri, 18 Jan 2019 17:28:52 +0000 http://www.electro-tech-online.com/threads/high-switching-speed-high-gpio-count-dev-board.155879/ http://www.electro-tech-online.com/threads/high-switching-speed-high-gpio-count-dev-board.155879/ invalid@example.com (glowbrain) glowbrain Hi All,

I'm looking for recommendations for a fast switching embedded controller to switch up to 155 GPIO pins within 10ns of a clock pulse.
Many of the FPGA solutions we looked at are clocked a little to slow to easily manage it (50Mhz), so a higher clocked Arm with dedicated code might be the go. But I'm open to suggestions. Up till now we've looked at the PicoZed, Zynq-7000, and the snickerdoodle. PicoZed doesn't quite have the pins (although we'd make do), and the snick is a little...

High Switching Speed, High GPIO Count dev board.]]> 8 Building a MIDI keytar Fri, 18 Jan 2019 17:18:36 +0000 http://www.electro-tech-online.com/threads/building-a-midi-keytar.155769/ http://www.electro-tech-online.com/threads/building-a-midi-keytar.155769/ invalid@example.com (MichaelaJoy) MichaelaJoy Hi all,
Firstly, I wanted to post this link, which demonstrates what a keytar is.


They give a good explanation, but what they don't tell you is that the Alesis key action leaves a lot to be desired.
I have the vortex 1 and, apart from nice functionality, the keybed is horrible.

So I did some shopping and I found the Roland A49...

Building a MIDI keytar]]>
How can you tell if a component will be immediately available in big quantities? Fri, 18 Jan 2019 15:09:03 +0000 http://www.electro-tech-online.com/threads/how-can-you-tell-if-a-component-will-be-immediately-available-in-big-quantities.155878/ http://www.electro-tech-online.com/threads/how-can-you-tell-if-a-component-will-be-immediately-available-in-big-quantities.155878/ invalid@example.com (Flyback) Flyback We have put one of the ECW-FD2J185K film capacitor into our PCB. It is 1.8uF,630VDC, and dimensions 25.3mm by 11.2mm by 16.5mm (= l x w x h).
In digikey and mouser this part is not immediately available in large quantities, in fact, only a few 100 pieces are immediately available.
This is a problem because it is a sure sign that this part will have supply issues…do you agree? (ie, if we get an order for 1000 boards say, then we probably won’t end up being able to quickly get enough...

How can you tell if a component will be immediately available in big quantities?]]>
Understanding Optimization/Realization of the voltage controlled current source. Fri, 18 Jan 2019 15:08:39 +0000 http://www.electro-tech-online.com/threads/understanding-optimization-realization-of-the-voltage-controlled-current-source.155864/ http://www.electro-tech-online.com/threads/understanding-optimization-realization-of-the-voltage-controlled-current-source.155864/ invalid@example.com (DX400) DX400 Hi,

I am unable to make a voltage controlled constant current source.
So I am using the following scheme (Sorry for bad sketch drawing):
The constant control voltage varies in the range of 0 to 5 V is applied by constant voltage supply (like HY3002 from e-bay) or (in what follows) by DAC output of PC-controlled board. So the control voltage is rather constant and linear.
The desired output parameters: constant current on load from 0.5 to 150 mA.
So, as a result...

Understanding Optimization/Realization of the voltage controlled current source.]]>
LED flasher does not work need help. Fri, 18 Jan 2019 15:01:28 +0000 http://www.electro-tech-online.com/threads/led-flasher-does-not-work-need-help.155852/ http://www.electro-tech-online.com/threads/led-flasher-does-not-work-need-help.155852/ invalid@example.com (gary350) gary350 I got this circuit online and I'm not very surprised that it does not work. I am not smart enough to fix it. :)

LEDs appear to be ON all the time but maybe they are blinking so fast they appear to be ON all the time?

LEDs are a bargin pack 100 for $3 about 5 years ago, they don't lite up very bright, won't be easy to see after dark on fake security system.

Circuit calls for 10uf capacitors, I changed caps to 100uf LEDs still appear to be on all the time. 1 blink every 2 seconds from...

LED flasher does not work need help.]]>
how easy is it to accidentally erase an eprom? Fri, 18 Jan 2019 08:31:30 +0000 http://www.electro-tech-online.com/threads/how-easy-is-it-to-accidentally-erase-an-eprom.155875/ http://www.electro-tech-online.com/threads/how-easy-is-it-to-accidentally-erase-an-eprom.155875/ invalid@example.com (fastline) fastline Long story short. I was working on an industrial control cabinet yesterday outdoors. Basically a 4x4x8ft tall control cab and then a small PC type enclosure inside that. The PC box door came open so I blew out the dust in it. The sun was not really out much and I know no direct light hit the chips but I didn't even realize until today the friggin UV erase windows are NOT covered? Who does that? In a high end industrial device? A little sticker maybe?

Anyway, they have some rather...

how easy is it to accidentally erase an eprom?]]>
Byte Shift Code Help Fri, 18 Jan 2019 08:13:07 +0000 http://www.electro-tech-online.com/threads/byte-shift-code-help.155883/ http://www.electro-tech-online.com/threads/byte-shift-code-help.155883/ invalid@example.com (Suraj143) Suraj143 I have 24 bytes & I need to shift bytes from D1 to D24, but the "New Data Byte" must feed into the 1st byte D1.
Below code I have, Can it be compact more than this?

        movlw    .24
        movwf    Temp
        movlw    D1        ;D1,D2,....D24
        movwf    FSR
        movf       New_Data,W
        movwf    INDF
        xorwf    INDF,W
        xorwf    INDF,F        
        xorwf    INDF,W
        incf       FSR,F
        decfsz  Temp,F...
Byte Shift Code Help]]>
hy Fri, 18 Jan 2019 06:49:27 +0000 http://www.electro-tech-online.com/threads/hy.155885/ http://www.electro-tech-online.com/threads/hy.155885/ invalid@example.com (Harryleo) Harryleo how question here but i am interset in travel]]> 0 ROLLVAC MP4500C Fri, 18 Jan 2019 06:02:09 +0000 http://www.electro-tech-online.com/threads/rollvac-mp4500c.155884/ http://www.electro-tech-online.com/threads/rollvac-mp4500c.155884/ invalid@example.com (roamer2017) roamer2017 Does anyone know what the heck a ROLLVAC MP4500C is I found this bulb with connectirs and what looks to be mercury inside the bulb. I cant find anything on it.]]> 0 Looking to purchase ESD brush set for cleaning PCB and other electronic gears ? Fri, 18 Jan 2019 04:59:45 +0000 http://www.electro-tech-online.com/threads/looking-to-purchase-esd-brush-set-for-cleaning-pcb-and-other-electronic-gears.155882/ http://www.electro-tech-online.com/threads/looking-to-purchase-esd-brush-set-for-cleaning-pcb-and-other-electronic-gears.155882/ invalid@example.com (zillah) zillah Dear Experts

I am a tech and I will be using them everyday , ,,,,looking to buy a quality set of anti static cleaning brushes something similar to the below link and there many others sources (but not sure of quality):


I found OXO brand but not as set...

Looking to purchase ESD brush set for cleaning PCB and other electronic gears ?]]>
74HC132 testing results Fri, 18 Jan 2019 04:18:49 +0000 http://www.electro-tech-online.com/threads/74hc132-testing-results.155869/ http://www.electro-tech-online.com/threads/74hc132-testing-results.155869/ invalid@example.com (earckens) earckens 50 74HC132 SOP-14 werd tested as freerunning oscillator. Two thirds failed: one or more gates of 4 per IC failed to act as oscillator (1M and 1uF). They were obtained from 2 or 3 sources, unfortunately I can't distinguish from which.
What is the forum's comment on this?]]>
Mesa-etching process Fri, 18 Jan 2019 04:02:18 +0000 http://www.electro-tech-online.com/threads/mesa-etching-process.155881/ http://www.electro-tech-online.com/threads/mesa-etching-process.155881/ invalid@example.com (AnahiiLeija) AnahiiLeija Can someone tell me about mesa-etching process? I translated that term but i can´t understand the definition. I´m hispanic.]]> 2 LM386 minimal circuit Fri, 18 Jan 2019 01:35:16 +0000 http://www.electro-tech-online.com/threads/lm386-minimal-circuit.155826/ http://www.electro-tech-online.com/threads/lm386-minimal-circuit.155826/ invalid@example.com (unclejed613) unclejed613 i remember a thread a while back where somebody wanted to use an LM386 amp, and they were trying to keep it simple. i found this in one of the 400+ page TAB circuit collection books. this one is about as simple as it gets...


all it needs is a battery and speaker.]]>
Design for a mains-powered rat zapper circuit Thu, 17 Jan 2019 23:49:10 +0000 http://www.electro-tech-online.com/threads/design-for-a-mains-powered-rat-zapper-circuit.155760/ http://www.electro-tech-online.com/threads/design-for-a-mains-powered-rat-zapper-circuit.155760/ invalid@example.com (owkaye) owkaye Our property has a rat problem. My goal is to build a powerful electric zapper that kills them by electrocution. The electrocution mechanism will be bolted to the top of a 55 gallon drum that's half-filled with water. After the rats are zapped they will drop into the water, and if any survive the initial deadly shock they will drown. A trap like this could kill hundreds of rodents before needing to be emptied, and this is one of my goals -- a trap that will work repetitively for weeks or...

Design for a mains-powered rat zapper circuit]]>
Need help interfacing pic24 to read a barcode scanner Thu, 17 Jan 2019 23:05:07 +0000 http://www.electro-tech-online.com/threads/need-help-interfacing-pic24-to-read-a-barcode-scanner.155880/ http://www.electro-tech-online.com/threads/need-help-interfacing-pic24-to-read-a-barcode-scanner.155880/ invalid@example.com (asmith34) asmith34 I need a pic24 (PIC24FJ1024GB610-I/PT) to connect and read from a 1D barcode scanner (Motorola LS2208-7AZR0100DR). With the research I've done I understand that using a plug-n-play barcode scanner with a usb interface will not work with a pic microcontroller but one with a DB-9 / RS-232 cable should. I am not sure how to get started. Could someone please offer some advice? I've attached spec sheet for barcode scanner. If I am missing details please let me know. Thanks!]]> 2 Need help with a hammond B3 project idea. Thu, 17 Jan 2019 21:06:26 +0000 http://www.electro-tech-online.com/threads/need-help-with-a-hammond-b3-project-idea.155638/ http://www.electro-tech-online.com/threads/need-help-with-a-hammond-b3-project-idea.155638/ invalid@example.com (JeffGee) JeffGee Hi all
I was wondering if anyone could help me I work with a band as an organ tech we have a beast of a Hammond b-3 player and I've done a little work on his expression pedal by adding a remote switch for changing the speeds of our Leslie speaker system.
I would like to install some LEDs inside the pedal that would change color with changing the speed of the spinning Leslie which is accomplished by taking on the toe switch I have installed.
Line voltage 120 volts goes through this ittle...

Need help with a hammond B3 project idea.]]>
gamma rays and solar panels Thu, 17 Jan 2019 19:50:55 +0000 http://www.electro-tech-online.com/threads/gamma-rays-and-solar-panels.155708/ http://www.electro-tech-online.com/threads/gamma-rays-and-solar-panels.155708/ invalid@example.com (m3vuv) m3vuv hi all,so i am lead to belive gamma rays are a high energy photon,does that mean a solar panel exposed to them would output electritcity? m3vuv.]]> 6 C, neat way to convert ascii float to int Thu, 17 Jan 2019 16:55:44 +0000 http://www.electro-tech-online.com/threads/c-neat-way-to-convert-ascii-float-to-int.155837/ http://www.electro-tech-online.com/threads/c-neat-way-to-convert-ascii-float-to-int.155837/ invalid@example.com (dr pepper) dr pepper I'm receiving a percentage from a machine controller over rs232, it insists on sending me a percentage to 9 decimal places.
I only want a percentage integer no decimal.
I'm trying to think of a neat way to convert 10.000000001% to 10%.]]>
please help identify a smd component, thanks K2134 Thu, 17 Jan 2019 15:13:47 +0000 http://www.electro-tech-online.com/threads/please-help-identify-a-smd-component-thanks-k2134.155872/ http://www.electro-tech-online.com/threads/please-help-identify-a-smd-component-thanks-k2134.155872/ invalid@example.com (wyalin) wyalin Hi, I am new here, thanks advance for the help.

This is from dell xps 9365 mother board, it is 5 pin, marked with k2134. Can not find it from anywhere. Appreciated if you could help me identify it and tell me the substitute or buying website.]]>
When I will use bass radiator passive speaker and how? Thu, 17 Jan 2019 14:26:14 +0000 http://www.electro-tech-online.com/threads/when-i-will-use-bass-radiator-passive-speaker-and-how.155871/ http://www.electro-tech-online.com/threads/when-i-will-use-bass-radiator-passive-speaker-and-how.155871/ invalid@example.com (learning) learning I want to know about when I can use bass radiator passive speaker for speaker box design and how I can do it? Please tell me.]]> 2