Search found 1530 matches

by lyndon
Wed Feb 14, 2018 10:53 pm
Forum: Projects
Topic: Heated pouch project idea, no idea where to start
Replies: 1
Views: 21

Re: Heated pouch project idea, no idea where to start

You need to know 1) The temperature on the outside of the pouch as well as on the inside 2) The heat transfer coefficient of the material (how well it insulates) 3) Newton's cooling law: https://physics.stackexchange.com/questions/277074/how-to-find-the-power-required-to-maintain-object-temperature-...
by lyndon
Mon Feb 05, 2018 5:56 am
Forum: Arduino
Topic: Testing if a 230v AC circuit is closed
Replies: 5
Views: 65

Re: Testing if a 230v AC circuit is closed

DanV's answer is the standard way of doing this and it's the most robust. No, you won't need a diode unless the switch contacts are really wimpy.
by lyndon
Fri Feb 02, 2018 5:17 am
Forum: Wireless/RF
Topic: HELP needed - wifi servo-motor control!
Replies: 4
Views: 105

Re: HELP needed - wifi servo-motor control!

The R/C car & airplane industry has been doing exactly this since the 50's without using microcontrollers. If you need potentiometer control of a servo wirelessly, there's no need for the Arduino. Where does the Arduino fit into all this? To answer your question specifically, a 555 pulse generator r...
by lyndon
Thu Feb 01, 2018 2:42 pm
Forum: Arduino
Topic: Trying To Measure Impact Force?
Replies: 6
Views: 90

Re: Trying To Measure Impact Force?

1) Remove all delays from your code 2) Put a photo sensor just above the impact point 3) Sample the photo sensor 4) When it triggers, start sampling the analog input at full speed and save data 5) Replay the data and see how it looks. If it still looks "all over the place" then you need to stop usin...
by lyndon
Sat Jan 20, 2018 11:15 am
Forum: Wireless/RF
Topic: Remote Control Garden Wagon
Replies: 2
Views: 240

Re: Remote Control Garden Wagon

It's basically a scaled-up mobile robot. Use two drive wheels and then you can implement skid steering. For a speed controller, look into wheelchair speed controls, or this: https://www.robotshop.com/en/cytron-30a-5-30v-single-brushed-dc-motor-driver.html The https://www.4qd.co.uk/knowledgebase/ sit...
by lyndon
Fri Jan 19, 2018 5:21 am
Forum: Arduino
Topic: how to connect am receiver to arduino
Replies: 5
Views: 151

Re: how to connect am receiver to arduino

What do you want to do with the receiver?
by lyndon
Fri Jan 19, 2018 5:19 am
Forum: Projects
Topic: Detect when the watch is inside the box
Replies: 2
Views: 162

Re: Detect when the watch is inside the box

Simplest way is probably an IR emitter/detector pair inside the box.
by lyndon
Tue Jan 02, 2018 12:06 pm
Forum: Arduino
Topic: Samd21, ADXL345 and SPI
Replies: 1
Views: 116

Re: Samd21, ADXL345 and SPI

The SPI drivers on the Cortex MCUs uses different code than SPI on the Arduino Uno. Be sure you have the right version.
by lyndon
Tue Jan 02, 2018 12:04 pm
Forum: Arduino
Topic: interfacing AD5752 with Arduino
Replies: 5
Views: 189

Re: interfacing AD5752 with Arduino

Unless there is something particularly special about the AD5722, I'd suggest using a DAC that already has Arduino libraries and using an op-amp subtractor on the output to get the +/- signals. You'll need the op amp anyway, for just about any bipolar DAC. This is pretty easy to use: https://www.spar...
by lyndon
Tue Nov 07, 2017 8:37 am
Forum: Projects
Topic: replace SPDT with button and indicator
Replies: 4
Views: 168

Re: replace SPDT with button and indicator

Simplest way is to use a 4017 counter with the pushbutton on the Clock input and your LED on the Output 0 output. Connect RESET to ground and Enable to +5V. Each button press toggles Output 0 on and off.
by lyndon
Fri Oct 27, 2017 9:24 am
Forum: SparkFun Product Questions
Topic: Very Low Constant Current
Replies: 5
Views: 271

Re: Very Low Constant Current

Is there any reason you won't use something far simpler like a current mirror or phalanx's suggestion of a purpose-built IC to do the job?
by lyndon
Tue Oct 24, 2017 7:57 pm
Forum: SparkFun Product Questions
Topic: Change MAC Address on Pro Micro?
Replies: 5
Views: 220

Re: Change MAC Address on Pro Micro?

n1ist wrote:They are programmable on the ATMega line, but it will require recompiling and reprogramming the firmware.
Good to know. I've only set PID/VID on stand-alone USB converter chips.
by lyndon
Tue Oct 24, 2017 11:21 am
Forum: SparkFun Product Questions
Topic: Change MAC Address on Pro Micro?
Replies: 5
Views: 220

Re: Change MAC Address on Pro Micro?

Probably not. THose are typically OTP: one-time programmable regions in the device memory.