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by Mistertee
Mon Oct 19, 2015 2:35 pm
Forum: Beginners
Topic: Multiple sensor monitoring via wireless
Replies: 2
Views: 3443

Re: Multiple sensor monitoring via wireless

Here is a neat solution to remote temperature monitoring.
http://mistertee-talks-electronics.blog ... .html#more
by Mistertee
Tue Mar 17, 2015 9:30 pm
Forum: Automation, sensing and robotics
Topic: Temperature Measurement
Replies: 0
Views: 551

Temperature Measurement

This application note shows the hardware and Python code required to measure temperature using the Raspberry Pi. Any of the Raspberry Pi models can be used including B, B+ and the Raspberry Pi 2. The beauty of this project is that there is no need for calibration when using the TMP36 device. http://...
by Mistertee
Tue Dec 23, 2014 9:34 pm
Forum: General discussion
Topic: books b+ and makey makey
Replies: 16
Views: 1822

Re: books b+ and makey makey

Have a look at this one called "Raspberry Pi with Custard" on Amazon available as a e-book and print version
by Mistertee
Fri Oct 17, 2014 9:52 pm
Forum: Automation, sensing and robotics
Topic: Rpi and relay to switch on/off lights
Replies: 27
Views: 79336

Re: Rpi and relay to switch on/off lights

Be very careful when dealing with mains voltages. Use a Power Tail Switch (from USA) or Mains Switch Widget (from UK). These take care of all the safety issues. The UK product has a fuse as well to prevent fires.
by Mistertee
Sun Sep 28, 2014 6:49 pm
Forum: Automation, sensing and robotics
Topic: 240v Traffic lights
Replies: 2
Views: 950

Re: 240v Traffic lights

Here is a module that is designed for use by non-electricians to switch mains on and off. It comes in kit form and needs soldering.
http://mistertee-talks-electronics.blog ... idget.html
by Mistertee
Sun Sep 28, 2014 6:45 pm
Forum: Troubleshooting
Topic: Problem Reading a loadcell with Raspberry Pi
Replies: 23
Views: 3825

Re: Problem Reading a loadcell with Raspberry Pi

Glad to hear that things that you have things working. Here is a link to a much simpler circuit using just a simple op-amp and a Custard Pi 8 input analogue card. If you keep things simple there is much less to go wrong. http://mistertee-talks-electronics.blogspot.co.uk/2014/02/weighing-scales-proje...
by Mistertee
Sun Sep 28, 2014 12:09 pm
Forum: Beginners
Topic: Battery testing and data logging
Replies: 2
Views: 656

Re: Battery testing and data logging

Here is a link to a blog post showing sample Python code and hardware on how to use the Raspberry Pi to measure an anlogue voltage. This example is for a weighing scale but it can easily be adopted to measure battery voltage. http://mistertee-talks-electronics.blogspot.co.uk/2014/02/weighing-scales-...
by Mistertee
Sun Sep 28, 2014 12:07 pm
Forum: Beginners
Topic: arduino
Replies: 7
Views: 923

Re: arduino

Here is a link to a blog post that shows how an op-amp can be used for level conversion when sampling an analogue input.
http://mistertee-talks-electronics.blog ... -cell.html
by Mistertee
Sun Sep 28, 2014 12:05 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO: Analog Input?
Replies: 16
Views: 92364

Re: GPIO: Analog Input?

To help hackers with no previous experience of using an analogue to digital convertor (ADC) here is a blog with schematic and sample Python code of a ADC in use.
http://mistertee-talks-electronics.blog ... -cell.html
by Mistertee
Wed Sep 10, 2014 3:15 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: connecting a light bulb with a Raspberry Pi
Replies: 7
Views: 6689

Re: connecting a light bulb with a Raspberry Pi

Take great care when switching mains. There is more to switching mains ON and OFF than just using the correct relay. One has to take into account the following: 1. The correct spacing on the PCB between the mains voltage side and the low voltage side 2. Anchoring the mains cable so that they do not ...
by Mistertee
Wed Sep 10, 2014 3:11 pm
Forum: Automation, sensing and robotics
Topic: Grove Relay board (solved)
Replies: 17
Views: 8500

Re: Grove Relay board (solved)

There is more to switching mains ON and OFF than just using the correct relay. One has to take into account the following: 1. The correct spacing on the PCB between the mains voltage side and the low voltage side 2. Anchoring the mains cable so that they do not accidentally pull out and touch other ...
by Mistertee
Sat May 24, 2014 9:55 pm
Forum: Teaching and learning resources
Topic: School RPi electrnic project
Replies: 0
Views: 1111

School RPi electrnic project

Nice project to teach soldering, surface mounted devices and a bit of Python programming to students interested in a career in engineering.

http://mistertee-talks-electronics.blog ... ry-pi.html
by Mistertee
Thu May 22, 2014 9:46 pm
Forum: Teaching and learning resources
Topic: STICKY: Free Python Books / Tutorials
Replies: 58
Views: 95981

Re: Free Python Books / Tutorials

Getting the Pi to send an a-mail when something happens - a step by step slideshow
http://www.slideshare.net/SeggySegaran ... -an-e-mail
by Mistertee
Thu Feb 13, 2014 5:01 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Using Slice of Pi/o and 16x2 LCD at the same time?
Replies: 30
Views: 6514

Re: Using Slice of Pi/o and 16x2 LCD at the same time?

On this page, there are links to a schematic and description of the Custard Pi 7 board, which has an LCD interface built on. It uses the I2C bus, so does not use any of the GPIO pins at all. http://www.sf-innovations.co.uk/custard-pi-7.html There is also a PowerPoint presentation with links to sampl...
by Mistertee
Thu Feb 13, 2014 4:56 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Connecting a 5V relay board
Replies: 20
Views: 14116

Re: Connecting a 5V relay board

There is a link on this page to a circuit diagram http://www.sf-innovations.co.uk/custard-pi-6.html

This uses an 8 channel driver IC (the ULN2801). This uses outputs directly from the GPIO and can drive a relay.
by Mistertee
Thu Feb 13, 2014 4:38 pm
Forum: Beginners
Topic: GPIO Update Rate/Speed
Replies: 9
Views: 4388

Re: GPIO Update Rate/Speed

Hi, not sure if this card will meet your sampling speed requirements - the only way is to try it and see. See here for an 8 channel 12 bit plug in A to D for the Raspberry Pi. The board has a chip that uses the SPI bus.
http://www.sf-innovations.co.uk/custard-pi-3.html
by Mistertee
Fri Oct 18, 2013 11:14 am
Forum: General discussion
Topic: Design flaw? Polyfuses for USB current limiting
Replies: 245
Views: 103126

Re: Design flaw? Polyfuses for USB current limiting

The Raspberry Pi has been designed down to a price of £25 to £35. Naturally there have been some compromises - one of them is to use a 5V 1A power supply.

The Polyfuse fitted makes complete sense. If you have problems with USB powering, just use a powered USB hub costing around £4.50.

Simples :)
by Mistertee
Sun Aug 18, 2013 6:02 pm
Forum: General discussion
Topic: choose a relay card
Replies: 24
Views: 8605

Re: choose a relay card

The relay card here does not need seperate drivers. However it needs a seperate 12V supply for the relay coils. http://www.sf-innovations.co.uk/custard-pi-6.html However I would still be very cautious about using this for mains switching. You need to really understand about electrical safety before ...
by Mistertee
Fri Aug 16, 2013 4:58 pm
Forum: General discussion
Topic: Raspberry Pi and 8 channel relay board
Replies: 7
Views: 9065

Re: Raspberry Pi and 8 channel relay board

On a more serious note though: Have taken on board the comments about the price. In fairness, this is not a valid comparision as this example compares an off the shelf product (Custard Pi 6) with one that does not exisit (combining exisiting products with a GPIO expander). The latter approach needs...
by Mistertee
Tue Aug 13, 2013 9:04 pm
Forum: General discussion
Topic: Getting started with the electronics side
Replies: 7
Views: 19019

Re: Getting started with the electronics side

Here are some basic PowerPoint tutorials that may be of help.

http://www.slideshare.net/SeggySegaran/ ... ng-started

http://www.slideshare.net/SeggySegaran/ ... ing-python

These are aimeds at absolute beginners. If you have any problems please let me know.
by Mistertee
Tue Aug 13, 2013 8:57 pm
Forum: General discussion
Topic: Raspberry Pi and 8 channel relay board
Replies: 7
Views: 9065

Re: Raspberry Pi and 8 channel relay board

I guess we can both agree on the stupidity of the Pentagon :D
by Mistertee
Tue Aug 13, 2013 11:45 am
Forum: General discussion
Topic: Raspberry Pi and 8 channel relay board
Replies: 7
Views: 9065

Re: Raspberry Pi and 8 channel relay board

It is priced at £36 which is competitive with the Pi Face (which is £28) but the Custard Pi 6 supplies much more. It is made in small quantities in the UK, so not cheap and cheerful China prices I am afraid. The PCB can be supplied on it's own for a few £££s for someone to source the components and ...
by Mistertee
Tue Aug 13, 2013 6:48 am
Forum: General discussion
Topic: Raspberry Pi and 8 channel relay board
Replies: 7
Views: 9065

Re: Raspberry Pi and 8 channel relay board

Here is a link to a dedicated Raspberry Pi 8 relay card that uses I2C control. This means that a number of these can be daisy chained to provide 16, 24, 32 .... upto a maximum of 64 relays.

http://www.sf-innovations.co.uk/custard-pi-6.html

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