2016-03-06 (Su) Cyborg Heart Rate Sensor

A 2N3904 transistor was added to the circuit in order to get more power through the coil and boost the magnetic output. A 2N3906 transistor could have also been used if the circuit were designed to switch on the positive side of the load.

Controller, transistor, and coil

Switching with the transistor improved performance because it was easier to feel magnetic pulses from a heartbeat or an oscillating program. A diode was never added to the circuit to protect the controller and was likely the reason the controller stopped responding. The controller was discarded and a virtually identical replacement was substituted but instead of soldering all the components directly to the board they were divided into two halves.

The first half was the heart sensor and coil which were intended to mount on the finger containing a magnet. Standard header connectors, DuPont connectors, were used because they were stocked and simple to change components.

Heart sensor and coil with DuPont connectors

The second half was the controller and transistor. This half was not necessary to be near the finger so the bulk could be moved closer to the battery. Previously the transistor stood far out from the controller but this time the leads were covered in shrink tube and the transistor was held close to the board.

Controller and transistor with DuPont connectors

Both halves were easily connected with long header pins or DuPont wires and each time they tested well. The wires had stiff insulation and the sockets wouldn’t hold the pins tightly. This combination means the final product will need flexible wires soldered to the components in order to be viable.

 Both halves connected with long header pins

Both halves connected with DuPont wires

The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1.
Completed projects from year 2

This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.

All information in this blog, or linked by this blog, are not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.

All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.

Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim claim property or assets based on their post.

This blog, including pictures and text, is copyright to Brian McEvoy.

2016-02-24 (W)