Triangle Wave Generation

triangle.py

import numpy as np
import scipy.io.wavfile

# generate a "canonical" waveform
elements = []
for i in range(0, 255):
    for k in range(20):
        elements.append(i)
for i in range(255, 0, -1):
    for k in range(20):
        elements.append(i)

# Figure out how many elements we should skip per step to acheive our target frequency
target_frequency = 220.0
base_frequency = 44100.0 / len(elements)
skip_amount = target_frequency / base_frequency

# stretch the array out a little bit, so our resolution is better
for k in range(4):
    elements += elements

# loop over the array skipping elements to acheive our target frequency
squashed = []
k = 0
while int(k) <= len(elements):
   squashed.append(elements[int(k)]) 
   k += skip_amount

# make sure we have enough samples to be a single second
while len(squashed) < 44100:
    squashed += squashed

# dump it to a wave file
squashed = np.array(map(np.uint8, squashed))
scipy.io.wavfile.write('triangle.wav', 44100, squashed)