Frequently asked questions

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General questions

Q. What is the difference between the old Turnoffee-Pi version 1.0 and the new version1.2?

A. Both versions of the hardware use the same software, but the hardware is slightly different, containing an extra resistor and LED. The red LED still lights up to inform you that the software is running and monitoring the switch, and flashes when the shutdown procedure is initiated, but the additional green LED, when it goes out, tells you it is safe to pull the power or remove the SD card from the Raspberry Pi.

Q. Which Raspberry Pi models is the Turnoffee-Pi compatible with?

A. All versions of the Raspberry Pi up to, and including, the Raspberry Pi 2 and Pi Zero (i.e. Raspberry Pi 2, Zero, Model B, Model B+, Model A, and Model A+). Please note that the Raspberry Pi Zero is not supplied with header pins, so this will need to be considered.

Q. How do I connect the Turnoffee-Pi to a Raspberry Pi Zero?

A. Please note that the Raspberry Pi Zero is not supplied with header pins, so pins will need to be obtained and soldered to the Zero. Once this is done, the Turnoffee-Pi can be attached in the normal way.

Q. Can I use the Turnoffee-Pi to kill the power and restart my Raspberry Pi?

A. No. The purpose of the Turnoffee-Pi is to safely initiate a shutdown of the Raspberry Pi using a piece of hardware that is relatively cheap to produce. This process ensures that the SD card is protected from corruption. When the shutdown completes, you can pull the power if necessary, safe in the knowledge that the correct procedure has been followed. Further hardware could be added to automatically kill the power and provide a startup button, but that would make the Turnoffee-Pi more expensive, and you could do the same thing by toggling the button on a power switch or disconnecting and connecting the power cable.

Q. Can I repurpose the Turnoffee-Pi and use it for something else?

A. Yes, most certainly. The Turnoffee-Pi is essentially a switch and visual indicators (the LEDs) on a very compact board. It's the software that tells it what to do. If you have the time and basic programming skills you can write your own programs to, perhaps, take a photograph when the button is pressed, or send an email etc. There are plenty of tutorials on the web, and the Python programming language provides an easy introduction to learning these skills.

The hardware

Q. Which GPIO pins does the Turnoffee-Pi use?

A. When assembled with the header, the red LED uses pin GPIO17, the green LED uses pin GPIO14, and the switch uses pins GPIO4 and 3v3. The GND pin is also used. If you opt to attach a fly-lead instead of the header, you can use different pins instead of GPIO14, GPIO17 and GPIO4.

Q. Can I replace the 2x6pin header with a stackable header, and then use jumper cables to connect the unused pins to my breadboard?

A. Yes. The board only uses pins GPIO4, GPIO14 and GPIO17 (and 3v3 and GND) - the other pins are dead ends, so you could use a 2X6 pin female header with extended legs passed through the top of the board and soldered from below, and then connect the other pins to your breadboard with male/male jumper cables. However, you will need to extract the metal leg from the header correspondng to pin GPIO1 before soldering the header. You can do this easily with a pair of long nose pliers. The leg needs to be removed because there is no hole in the circuit board at that position.

Q. What are the dimensions of the assembled kit?

A. The measurements are as follow:.

Height with header: 16.5mm
Height without header: 8mm
Width: 19.5mm
Depth: 16.5mm

When mounted on the GPIO pins, 10mm height is added to the Raspberry Pi.

The software

Q. Do I need to install software on my Raspberry Pi for this to work?

A. Yes, software like "turnoffee.py" is necessary to monitor the relevant GPIO pin for button presses. turnoffee.py is provided free of charge via a download link, as a courtesy, and was developed for the Raspbian OS. It will also work with other Raspberry Pi operating systems which have Python and the necessary libraries installed. You can, if you prefer, write your own software.

Q. How efficient is the software, with respect to CPU?

A. The script makes use of an interrupt based handler, which, for the purposes of this type of device, is considerably more efficient in terms of CPU usage and resources than a polling method. When working with relatively low powered devices like the Raspberry Pi, this can be critical.

Troubleshooting

Q. The red and/or green LED doesn't light up on my board. Why?

A. The most likely reason for this is that the LED has been inserted into the holes on the PCB the wrong way round. You can visually check this by holding the Turnoffee-Pi up in front of your eyes so that you are looking directly at the two LEDs, with the green on the left and the red on the right. Inside each LED you will see a triangular piece of metal, a bit like a flag. These flags should be pointing in opposite directions, with the "mast" in the middle. If you made a mistake here, you will need to desolder the LED and insert a new one.

Another reason that the LED might fail is that it was overheated during soldering. Check that the metal inside the LED hasn't melted its way through part of the LED plastic casing. If it has, you will need to remove it and solder in a new one.

If the LEDs appear to be fine, check for cold solder points on the PCB, and resolder them if necessary. Also check for solder "bridges" between components that shouldn't be connected.

If it's the red LED that isn't working, check that the turnoffee.py software is running. It's the software that writes to the GPIO pin to tell the LED to light up.

Q. The red and/or green LED lights up on my board, but it is extremely dim. Why?

A. This sounds like the resistors have been mixed up. Check that the three resistors have been soldered in the correct positions on the PCB.

Payment, postage and delivery

Q. What payment methods are acepted?

A. Payments are only accepted through PayPal.

Q. When will I receive my item(s)?

A. Items are normally despatched within 24 hours, although ready assembled items may take up to 48 hours to be despatched. Delivery charges are included in the price, and postage is via Royal Mail 2nd class.

Q. Do you ship internationally?

A. Unfortunately, no, not at the moment. Items will only be shipped to UK addresses.