# DIY eChook Buying a kit isn't everyone's cup of tea. In fact, we see the eChook kit as a first stepping stone to instrumenting a car and hope teams will be able to move on to custom designs to satisfy their needs. Everything we have created except for the telemetry is open source. This means you can use as much or as little of it as you want in your designs. If you have PCB etching facilities then designing your own PCB, potentially reusing the eChook circuit schematics to create a custom system might be an excellent project, or if you have an existing data logging board, you may be able to connect a bluetooth module and be able to use the eChook app and telemetry to get some good real time data in the pits. See the Bluetooth Communication section for more details. For insurance reasons (ugh) we can't give you modifications to make to the eChook if you have bought one of the kits, but we are always happy to answer electronics questions - pop over to the [forum](http://www.echook.uk/support.html) or message us here. ## Purchasing the PCBs If you would like to buy just the PCBs and source the rest of the components yourself, you can now buy these through the eChook store: [shop.echook.uk](https://shop.echook.uk/?product_cat=greenpower). --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.echook.uk/diy-echook.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.