ECG on your laptop!

That's right! This Instructable shows you how to build a device that enables you to do an electrocardiogram on yourself, your family or your friends! All you need is intermediate-level knowledge on electronics, access to Ye' Ol' Electronics Shoppe (or online shopping if preferred) and a laptop.

The device is composed of an amplifier/filter and a microprocessor unit, everything surrounded by a metallic box to avoid interferences.

Safety warning: DO NEVER use devices like this with a regular computer, as it is not isolated from the electrical power network. It may kill you in case of an electrical anomaly!

Information about the authors: we are students living in Portugal and we developed this device for our school project named Palpita-me! (Beat in me!, says the heart). With our project we intend to alert the school community and the general public to the importance of the prevention of cardiovascular diseases. We are studying issues such as the circulatory system, its anatomy, physiology and measurable parameters, relevant diagnostic techniques (especially electrocardiography), hospital services and emergency, telemedicine, statistics and risk factors.

Take good care of your heart so that it will beat inside you for many happy years to come!

Feel free to visit our website and leave us a comment. We'd love hearing from you!

Step 1: Plans, schematics and board layout

Our ECG amplifier/filter board schematics is derived from an Analog Devices application handbook. We adapted and complemented it to suit our needs and we used PCB123 Schematic to draw the circuit schematics. Then, we used PCB123 Layout to draw the actual board. PCB123 is a great program and it's entirely free, so you can get it here.

The microprocessor unit was made by a member of our team some years ago and at its core lies a PIC microcontroller.

To plot data on a laptop screen, we needed software that could simulate an oscilloscope. For that we used the excellent (and free) Oscilloscope.dll, written by Michael Bernstein. We thank him for his kind support.

Furthermore, we also prepared a list of components that is just too big to show up here. From our website, you can download this list, every schematic and layout we've made.

Comments

[x-avis]

Hi I have one request can you send to my e-mail amplifier, Additional 50 Hz notch-filter, and Microprocessor unit schematic plans? and + program for microprocessor :) why your website (www.palpita-me.org) doesn't work? My e-mail: [e-mail] VERY HUGE THANK YOU

[legolas11007]

I have a question to the PCB. When you finished designing it, it says in the video you ordered it. Can you tell me where you placed this order? I want to give this project a go. Thank you!

[JZweige]

When we finished designing it, we exported it to a .pdf file. Then, we took this file to a local electronics shop in our town and we ordered it.

In your case, I believe it is possible to order the bare board from PCB123 itself, since they sell boards too.

Good luck in your projects!

[legolas11007]

Can you tell me how much the custom PCB cost when you ordered it from your local store? Thank you

[JZweige]

It was about 15€, that is 20$ (USD).

[michaelgohjs]

will it fry the IC?

[JZweige]

As soon as the solder paste changes color into a bright, silver finishing (releasing a bit of smoke), you should carefully pull off the pcb and let it cool down. Also, in order to avoid overheating, you should use some metal bars close to the pcb edges as spacers so that the pcb remains always some 2 millimeters above the hot plate. This helps both to make the heating more uniform across the pcb and to avoid overheating, while providing a slot underneath the pcb for extraction: a metal ruler is inserted under the pcb and then lifted.

[JZweige]

If you're careful it won't. We had a bit of bad luck and we let the board there for too long and it became a bit... "brownish" in the parts which caught most heat, but it works perfectly.

If we were in a professional electronics lab, there would be a specialized oven to do this. But we were in school's workshop o.O :D

[chrisw123]

how did you connect the ecg machine to you? and did you have special wire, when i tried normal wire just caused too much noise?

[flamekiller]

Try using some sort of shielded wire. A common source of interference for ECG machines is fluorescent lighting, so see if that is a problem as well.

[JZweige]

We used unshielded leads away from any power line, lamp or other sources of electromagnetic noise.

[dgalvarez]

Is it possible to obtain the schematics and the pcb layout?? We cant access to your webpage and it´s too sad to loose this project. Thank you so much. If the builder doesn´t answer. Could anybody send to me those archives?

[JZweige]

Hi! Due to technical issues, the site had some downtime :(

But now you can access all files from the new address: http://palpita-me.esms.edu.pt/node/116

I am sorry for the inconvinience and thankful for your interest on our project!

[1tri2god]

Great 'ible!!! My wife just got back from Haiti teaching their version of EMS the basics of CPR. She was frustrated because she couldn't teach coronary life support because the ems, AND THE FIELD HOSPITALS didn't have an ekg machine, portable or otherwise! While there is better out there...we'll try this out on the next trip with spare units until we can get something professional! Great job guys!

[MikB]

"DO NEVER use devices like this with a regular computer, as it is not isolated from the electrical power network."

Also do not interconnect the laptop with any *other* devices that are mains powered -- not the battery charger/power pack for the laptop, not to your stereo, or to phone lines, broadband, internal wired networks, external antennas etc. All of these introduce possible paths for hazard currents to flow through you.

Real ECG machines are fully isolated to many thousands of volts, so there is no hazard. Toy ones are battery operated and stand-alone. There is a reason for this!

[JZweige]

Exactly! Excellent advice!