Bitcoin Clock

[A Former User]

Hey Onioneers,
Today I wanted to share a project : the Bitcoin Clock.

This Omega2+ based project displays Bitcoin price on a LCD. A strip of LEDs blinks red when price drops, and green when it goes up.

You'll need a LCD i2c display (1602), an Onion Omega 2+ with a dock (I've got a Power Dock so I'll be able to power it with a LiPo battery), and a LED strip.
I used to make projects with addressable LEDs (like WS2811…) but this time, I choose a simple RGB strip working like a RGB LED.

I installed FireI2CLCD : http://davidstein.cz/onion-omega-firei2clcd-lib/
As the i2cdetect command doesn’t work well, I tried a few i2c addresses, mine was 0x27

When everything was ok, I just put my python file in /etc/rc.local to run my command on boot.

       # Put your custom commands here that should be executed once
       # the system init finished. By default this file does nothing.
        
       python /root/helloBitcoin.py
       python /root/bitcoin.py
          
       exit 0

The command helloBitcoin.py displays "Bitcoin Clock" on boot before the principal command.

       import time 
       import omega_gpio
       import lcddriver
       import i2c_lib

       lcd = lcddriver.lcd(0x27)
       lcd.lcd_clear()
       lcd.backlightOn()
       lcd.lcd_display_string(" BITCOIN CLOCK ",1)
       time.sleep(7)
       lcd.backlightOff()

Here is the idea : (Don't pay attention to the scale, I drew this with Paint)

First try (without LCD) :

Laser Cutting :

And it works !!

Here is the code :

# BITCOIN CLOCK - A Dorize - OnionIoT - Powered by coindesk.com API 

import time							
import urllib                                                                                                         
import json                                                                                                                  
import omega_gpio
import lcddriver
import i2c_lib

lcd = lcddriver.lcd(0x27)			# Init LCD

omega_gpio.initpin(3,'out')			# Init LEDs
omega_gpio.initpin(2,'out')
omega_gpio.setoutput(3, 1)
omega_gpio.setoutput(2, 1)

prevprice = 4500.000                      	# Nevermind, first blinking

while True:

	lcd.lcd_clear()
	lcd.backlightOn()									
	x = 0
	site="https://api.coindesk.com/v1/bpi/currentprice.json" # JSONrequest
	jfile=urllib.urlopen(site)                                                                                                   
	jsfile=jfile.read()
	a=json.loads(jsfile)
	price=a['bpi']['USD']['rate'] 	      # need number in bpi>USD>rate
	price=price.replace(",","")	# Some cleaning
	priceEUR=a['bpi']['EUR']['rate']
	priceEUR=priceEUR.replace(",","")

	info="1 BTC = " + str(price) + " USD"		# Serial info
	print info

	lcd.lcd_display_string("1 BTC =",1)		# LCD info
	lcd.lcd_display_string(str(price)+" USD",2)


	if float(price)>prevprice:			# Green blinking
		for x in range(0, 7):
			omega_gpio.setoutput(3, 0)
			time.sleep(0.2)
			omega_gpio.setoutput(3, 1)
			time.sleep(0.2)
			x +=1
		time.sleep(15)
	
	elif float(price)<prevprice:			# Red blinking
		for x in range(0, 7):
		
			omega_gpio.setoutput(2, 0)
			time.sleep(0.2)
			omega_gpio.setoutput(2, 1)
			time.sleep(0.2)
			x += 1
		time.sleep(15)	
	
	elif float(price)==prevprice:		# backlightOff can be removed
		lcd.backlightOff()
		time.sleep(15)
	
	infoEUR="1 BTC = " + str(priceEUR) + " EUR"     # EUR Serial info
	print infoEUR

	lcd.lcd_clear()
	lcd.lcd_display_string("1 BTC = ",1)		# EUR LCD info
	lcd.lcd_display_string(str(priceEUR)+" EUR",2)	

	time.sleep(15)

	prevprice = float(price)			# Price update

It's a prototype yet, but it works. Next step I will build another "clock" for Litecoin, maybe 3D printed.

I hope you enjoyed this tutorial

BTC Tips : 3JRf2GaHsGs9c1naxAn8TN3HN4S1y5hUoG

Have a nice day Onioneers

[James Harding]

Very nice! I wouldn't mind having one of these. I think it would be cool if you made the face of the 'bitcoin' a pie chart, and had different crypto currencies with their own LEDs under each piece of the pie. Then you could use one omega to report a bunch of different crypto currency rates.

How many watts is your laser cutter? That looks like its gotta be pretty powerful, 100 watts?

[A Former User]

@James-Harding Good idea ! Thank you, I'll think about it.
It's not my laser cutter, I use a Trotec Speedy 400 so it's very powerful

[Rongomai Bailey]

Don't need to do all that cleaning...

you should be able to just select the first item in the list to get clean JSON data which is recognised as a dictionary.

a=json.loads(jsfile)[0]

should work... have only been using python for 2 hours tho!

[A Former User]

@Rongomai-Bailey Cleaning is just to translate a X,XXX.XXXX price into a float XXXX.XXXX

[Rongomai Bailey]

@Antoine-Dorize oh yes now I see!

my bad - was thinking of the stock ticker example

[Csaba Csanaki]

I get a following error:

Traceback (most recent call last):
File "bitcoin.py", line 27, in <module>
a=json.loads(jsfile)
File "/usr/lib/python2.7/json/init.py", line 339, in loads
return _default_decoder.decode(s)
File "/usr/lib/python2.7/json/decoder.py", line 364, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "/usr/lib/python2.7/json/decoder.py", line 382, in raw_decode
raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded

I modify the line27 - but the error is same:

Traceback (most recent call last):
File "bitcoin.py", line 27, in <module>
a=json.loads(jsfile)[0]

Can you help for me, how could I fix it?

Thanks a lot!