Search found 1570 matches

by lyndon
Tue Jun 12, 2018 5:53 pm
Forum: Projects
Topic: help with code to control 32x64 matrix with mega 2560
Replies: 2
Views: 47

Re: help with code to control 32x64 matrix with mega 2560

I'll give you $20 for your Beaglbone (seriously!).
by lyndon
Tue Jun 05, 2018 4:33 am
Forum: Projects
Topic: Convert a circuit from 24 to 12vdc
Replies: 6
Views: 115

Re: Convert a circuit from 24 to 12vdc

There are more modern ways of control. You can probably find a valve to suit your needs that's digitally controlled and avoid the whole 4-20mA debacle since you're starting with an Arduino.
by lyndon
Mon Jun 04, 2018 10:10 am
Forum: Projects
Topic: Convert a circuit from 24 to 12vdc
Replies: 6
Views: 115

Re: Convert a circuit from 24 to 12vdc

Try it and see. My gut tells me it'll probably work (at 15V, I'd be more certain), since it's only 20mA max, so the transistors don't need to be saturated. It's probably designed for 24V supply because that's a common supply voltage for industrial equipment. That said, I'm sure you could find a simp...
by lyndon
Tue May 29, 2018 11:15 am
Forum: Arduino
Topic: Help configuring Arduino to trigger DI on IP-camera
Replies: 3
Views: 63

Re: Help configuring Arduino to trigger DI on IP-camera

I covered this in my PM, but to anyone using this project as a future reference: an ultrasonic sensor would probably have fewer false positives than an IR sensor outdoors.
by lyndon
Sun May 27, 2018 6:20 pm
Forum: Arduino
Topic: Help configuring Arduino to trigger DI on IP-camera
Replies: 3
Views: 63

Re: Help configuring Arduino to trigger DI on IP-camera

My first order of business would be to figure out how to detect the truck. My suggestion is a photoelectric through-beam sensor with the emitter and detector facing each other across the queue. A coil under the ground would probably be more durable, but then you have to dig up the concrete! That's r...
by lyndon
Fri May 25, 2018 11:51 am
Forum: Arduino
Topic: Newbie here and proposed project.
Replies: 4
Views: 96

Re: Newbie here and proposed project.

Actually that sounds like a lot more fun to me... Guessing from your use of the term "smallholding" you're in the UK? Can you purchase firecrackers or other small incendiaries? I can see setting up an Arduino to fire one off every 10 minutes or so. Or find a truck airhorn on eBay and have a compress...
by lyndon
Thu May 24, 2018 11:36 am
Forum: Arduino
Topic: Newbie here and proposed project.
Replies: 4
Views: 96

Re: Newbie here and proposed project.

My neighbor who has a small vineyard, covers the vines with netting when the grapes are getting ripe.
by lyndon
Tue May 22, 2018 4:16 am
Forum: Projects
Topic: Circuit to detect 120VAC with 3.3VDC micro
Replies: 2
Views: 82

Re: Circuit to detect 120VAC with 3.3VDC micro

The simplest way I've done this before is to use a relay with a 120VAC coil and sense the contact closure just as you would any other switch.
by lyndon
Mon Apr 30, 2018 5:07 am
Forum: Projects
Topic: External Memory Device for 8-Bit Computer?
Replies: 4
Views: 146

Re: External Memory Device for 8-Bit Computer?

Sorry, mistyped. I meant Z80-SIO. Use serial comm to PC to upload your program.
by lyndon
Sat Apr 28, 2018 2:35 pm
Forum: Projects
Topic: External Memory Device for 8-Bit Computer?
Replies: 4
Views: 146

Re: External Memory Device for 8-Bit Computer?

I might have an EPROM emulator in a box somewhere...
Alternately, you could write a serial bootloader and upload the program from a PC over the serial port. Have a Z80-CTC lying around?
by lyndon
Mon Apr 23, 2018 5:57 pm
Forum: Arduino
Topic: Splitting Strings - arduino
Replies: 2
Views: 112

Re: Splitting Strings - arduino

This will return an array of substrings using the delimiters " ,/" // Separate string into tokens inline void split(char* inVal, char outVal[NUM_WORDS][STRING_LEN]) { int i = 0; char *p = strtok(inVal, " ,/"); strcpy(&outVal[i++][0], p); while (p) { p = strtok(NULL, " ,/"); if (p) { strcpy(&outVal[i...
by lyndon
Thu Apr 19, 2018 7:37 pm
Forum: Projects
Topic: Waste Tank Discharge Project
Replies: 11
Views: 257

Re: Waste Tank Discharge Project

teprojects1:
You're not content to spam the groups, you also need to grossly overcomplicate a simple design? I'm all in favor of throwing microcontrollers every which way, but in this case, the entire solution can be done with a single DPDT relay or two SPDT relays.
by lyndon
Tue Apr 17, 2018 5:43 pm
Forum: Projects
Topic: Waste Tank Discharge Project
Replies: 11
Views: 257

Re: Waste Tank Discharge Project

Simplest way is to use a latching relay (or make a latching relay from a DPDT relay) that turns on when the upper float closes and turns off when the lower float opens. See http://www.reuk.co.uk/wordpress/electronics/latching-relay-circuit/ The "push to make" switch is your upper float and the "push...
by lyndon
Tue Apr 17, 2018 5:30 pm
Forum: SparkFun Product Questions
Topic: Best Relay for 1/2 HP 120v AC Motor (DIN rail maybe?)
Replies: 7
Views: 225

Re: Best Relay for 1/2 HP 120v AC Motor (DIN rail maybe?)

Don't panic :-)
It's not likely to fail if you run it within spec. I'm pointing it out because failing shorted is generally more problematic than failing open.
by lyndon
Tue Apr 17, 2018 7:43 am
Forum: SparkFun Product Questions
Topic: Best Relay for 1/2 HP 120v AC Motor (DIN rail maybe?)
Replies: 7
Views: 225

Re: Best Relay for 1/2 HP 120v AC Motor (DIN rail maybe?)

When SSR's fail, they tend to fail shorted, so think about an additional switch or a normally-on relay in the loop. Don't forget to properly heatsink the SSR if you're going to mount it on DIN rail.