I purchased most of my parts from Digikey
(and Amazon). Their layout might seem slightly intimidating at first glance, but they seem like the cheapest place to get parts. And they have the USPS first class shipping option ( < $3 for small orders, choose this! It will save you a lot.), meaning you don't have to spend the same amount on parts as shipping, as it is on some websites.
- 1x Instrumentation Amplifier - AD620AN
- This is the most expensive, and most important part. While technically you can make your own instrumentation amplifier from 3 op-amps, I could never get my own to give me good results. Precision cut resistors in this ensure that it'll do its job.
- 2x Quad Op-Amp - TL084CN
- Any Op-Amp will do. You need 5 single amps, this one just includes 4 in each chip.
I would strongly suggest buying a capacitor bundle from ebay or the like, espcecially if you plan on ever doing some other sort of electronic project. One bundle and you're basically set for life. Regardless, whether you buy them in a pack or individually, make sure to include these capacitors :
- 1x 10 nF, ceramic
- 1x 20 nF, ceramic
- 1x 100nF, tantalum
- 5x 220nF, tantalum
- 1x 1uF, electrolytic
- 2x 10uF, electrolytic
Same as capacitors, I suggest a bundle. This
is a very good one, has all the values you need (minus the potentiometer). The individual values you'll need, though, are:
- 1x 1kΩ Potentiometer - via Digikey
- very useful to adjust your gain on the fly.
- 2x 12Ω
- 1x 220Ω
- 1x 560Ω
- 2x 22kΩ
- 1x 47kΩ
- 2x 100kΩ
- 2x 180kΩ
- 1x 220kΩ
- 2x 270kΩ
- 1x 1MΩ
- A breadboard to wire everything on. This one
is large enough, and comes with useful jumper wires. I suggest saving the jumper wires specifically for connecting the various stages of the design. This will make it very modular, and easy to reorganize/reorder if you end up needing to.
for everything else. I like that pack, since it's pre-cut and keeps your board tidy. You can also get plain wire
and cut it yourself.
- 3.5mm audio cable
- 2x 9V batteries for power.
- Ambu Neuroline Cups seem to be the most cost-effective method, found here
. Thanks to user jonencar for the link in the comments.
- electrode gel