super simple pulse stretcher

Started by bitrex in sci.electronics.design7 years ago 37 replies

I have a need to take a square pulse of 0V/+5V and about 5-10ms duration, and stretch it out long enough to flash a LED brightly enough to be...

I have a need to take a square pulse of 0V/+5V and about 5-10ms duration, and stretch it out long enough to flash a LED brightly enough to be visible indoors under "ordinary" lighting conditions. I currently only have op-amps on the board and would rather not add any logic ICs to do this. So using low-speed op amps and discretes would be fine. The pulse source into the stretcher would...


Back to the Days of DOS

Started by Rick C in sci.electronics.design1 year ago 11 replies

I used to know DOS pretty well. I am copying a lot of files to a flash drive for backup and need to verify what has been transferred by comparing...

I used to know DOS pretty well. I am copying a lot of files to a flash drive for backup and need to verify what has been transferred by comparing directories. A simple count is sufficient. Trouble is I'm getting incomplete data. I'm using a DIR command to a file, then examining the files to see how many files are missing. My text editor can do a diff if the counts don't match. When I...


Atheros 9285 eeprom problem

Started by Anonymous in sci.electronics.design8 years ago 2 replies

My HP came with a Broadcom Wifi adapter, but i want to switch it to Atheros= . I got a few PCIe 9285 adapters. They are identical except for...

My HP came with a Broadcom Wifi adapter, but i want to switch it to Atheros= . I got a few PCIe 9285 adapters. They are identical except for the subsy= stem ID: The HP branded adapter did not work at first, but works after re-flashing i= t. The non-HP adapter works on another labtop but lockup the bios on the H= P, with non-supported device message. I am trying to re-flash the non-HP ...


Writing to MCU flash

Started by Phil Hobbs in sci.electronics.design4 years ago 108 replies

So we've got this custom product that includes a voltage-controlled amplifier. VCA chips as used in ultrasound and so on have nice low noise...

So we've got this custom product that includes a voltage-controlled amplifier. VCA chips as used in ultrasound and so on have nice low noise at the highest gains, but at low gain they stink on ice. The same is true of all transconductance-based VCAs unless you use a zillion stages. Sooo, we're faking it with a dpot, an op amp with a mux-controlled resistor ladder, and an LPC804 Cort...


trigger LED

Started by John Larkin in sci.electronics.design3 years ago 41 replies

I'm doing a small box that accepts a user trigger. I'd like to flash an LED every time it gets triggered. Something like 100 ms, on a...

I'm doing a small box that accepts a user trigger. I'd like to flash an LED every time it gets triggered. Something like 100 ms, on a blue LED. The obvious circuit is a 74lvc1G123 one-shot, set to 100 ms pulse width. But how fast will that work? I'd like to go to 50 or maybe 100 MHz. Would it keep retriggering? I wouldn't want the LED to go out at high trigger rates. There is a spec...


Nice MCU for small jobs

Started by Phil Hobbs in sci.electronics.design4 years ago 96 replies

LPC804: 15 MHz Cortex M0+, 32kB flash, 4k RAM, 12-bit 2 us ADC with 1 LSB DNL, 10-bit DAC, the usual serial stuff, 20-TSSOP: 67 cents in...

LPC804: 15 MHz Cortex M0+, 32kB flash, 4k RAM, 12-bit 2 us ADC with 1 LSB DNL, 10-bit DAC, the usual serial stuff, 20-TSSOP: 67 cents in reels, dev board $27. We're using it for a super-quiet diode laser controller where it will run the temperature control and automatic power control loops. I'll never use another ATmega. ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principa...


Denver SHO-110. 2 new wifi TUYA cameras fail to activate

Started by a a in sci.electronics.design3 months ago

Hi, I have 2 new Wifi cameras by Denver Denver Smart Home app fails to identify cameras nor they show in wifi scan on android...

Hi, I have 2 new Wifi cameras by Denver Denver Smart Home app fails to identify cameras nor they show in wifi scan on android smartphone What works is IR leds flash if covered with hand full name from the box WiFi-Flip outdoor smart camera Tuya Smart Home Compatible micro sd up to 128 GB there is ON click under cover failing to work either what's wrong ? Maybe WiFi ID ...