HamShield for Arduino

HamShield for Arduino


The HamShield Team

Morgan Redfield (KG7OGM) is our lead electrical engineer. He has worked on many embedded hardware applications and is active in the Arduino hardware community. He received his MsEE from the University of Washington in 2013 and teaches robotics and electronics to high school students in his spare time.

Casey Halverson (KC7IBT) is an Information Technology professional and Amateur Radio operator. He earned his license when he was 14 years old. After working years with Arduino hardware, he dreamed of one day combining the rapid prototyping capabilities of the Arduino environment with Amateur Radio. Casey is also a Chrome developer, bringing the first Arduino IDE and programmer to the Chromebook (Chromeduino). His hobbies also include software development and electronic design.

Nigel Vander Houwen (K7NVH) is an Information Technology professional, and an extra class amateur radio operator. He studied Earth and Space Sciences at the University of Washington, and spends his hobby time working on interesting electronic projects, including specialty radio telemetry devices used for high altitude balloons and high power rocketry. A drive for knowledge pushes Nigel to create new things, and explore new places in the beautiful Pacific Northwest he calls home.
Questions

Q. Where will HamShield be manufactured?

A. In the United States. We have a contract manufacturer lined up to build HamShields in Seattle, Washington. We will also be purchasing most of our components from a well known distributor in the USA as well. Our main radio SoC is sourced from China.

Q. What if I want more than 250mW?

A. If you need more power, connect HamShield to a linear amplifier! While there are many products available for purchase online, we are looking for a partner who can help make this purchase process more streamlined. More information and options will be available when the survey is sent out after the project is funded.

Q. Does this work on any other bands, such as GMRS, FRS and MURS?

A. Yes, technically, the HamShield can transmit and receive on any frequency within its 3 band range. In the United States, these bands typically require a special equipment authorization and have certain emission restrictions.The library only allows transmission on amateur radio bands, unless the lock out is specifically disabled for a lab setting (using the .dangerMode() method). Please check with your regulatory agency and do not transmit on any frequency that you are not licensed for. You are always free to receive any of the supported frequencies with the HamShield.



Q. Can this work with just a computer?

A. Yes, as long as you still have an Arduino to plug the shield into. Our Chrome app will program the Arduino automatically, so it is plug and play. There is a "serial glue" sketch that allows a computer to control all aspects of the radio over serial port, as well as use packet radio functions available within our packet library. This makes things like our Chrome app possible. It also allows you to create computer controlled devices.

Q. How do I get two shields to work simultaneously?

A. Maybe, with some possible limitations. Your best bet is to use two Arduinos and connect via serial. The radios have not yet been tested collocated and all the audio would be connected together. You can change the I2C address by disconnecting a resistor and you will also want to space out the antennas. You would have to interconnect the two audio jacks with a crossover to build a repeater. Two boards could not work independently with system audio without some re-soldering.

Q. What other data modes are supported?

A. We currently have only tested AFSK at 1200 baud. Higher baud rates, such as 9600, have not been tested yet and may not be possible. While low pass filters and emphasis can be disabled in software, there is still a DC blocking capacitor between the chip audio lines and the shield audio circuitry. If this is bypassed, it might bring full FSK capability to the radio. However, this is outside what was recommended by the manufacturer. We do not expect this will damage anything.You are at your own risk with this one.

Q. Is this a software defined radio?

A. No, but this is a good thing. The Arduino is not powerful enough for Software Defined Radio. The A1846S actually has a software defined radio core to make this not necessary.

Q. Can this modulate SSB, AM, GMSK, etc?

A. No. Only FM is supported. FM is by far the most popular mode on all supported bands, so you will be able to participate with most of the activities taking place on the ham bands today.

Q. Can I use the HamShield as a scanner?

A. Yes! Although the circuitry is not designed for high speed scanning, we have several scanning functions built into the library. You could even write code to log transmission times and record transmission audio to a computer.

Risks and challenges

We have worked hard over the past year to make sure we were in the final stretches of development before asking the public for support. We have waited until a working prototype was completed, and that a reliable design can be brought to manufacturing. That being said, there can be all sorts of unexpected hurdles in hardware development.

Here are some potential risks and how we plan to address them.

Business, Budget, Finance

All of us have a small business ownership background in one shape or another and have business finance experience. We decided to launch our Kickstarter the "right way" by forming an LLC, obtaining a tax ID, and business banking services. We have a budget, modeled our potential income, identified pitfalls, created wiggle room within our budget, and have spoken to several different successful Kickstarter launchers about what problems they ran into. Our operating agreement places the liability of Kickstarter fulfillment the absolutely most important company priority.

Funding Over 100%:

We also have a plan in place under the very fortunate event that we overfund. We have the capability to produce thousands of boards, under the assumption that key critical components do not have unexpected lead time. Members of the team are dedicated to completing the project and fulfilling orders quickly, no matter the number of awards.

Electronic Hardware Production:

All project members have experience in electronic production and assembly, and have used contract manufacturers in the past to produce commercial and non-commercial electronic products in the past. While we do not claim to be experts, we know what it takes to successfully take a design from an idea to full production of hundreds or thousands of boards.

We have suppliers lined up, and to the best of our knowledge, should be able to produce all shields ordered without any problems.

Some potential risks could result in a design flaw, either introduced by our team or a design problem introduced by the contract manufacturer itself. We plan on mitigating this by performing slightly more expensive trial runs before producing the full amount of boards. Even in the event of the worst case scenario of a full production run with a defect, we will have enough reserve funds to complete fulfillment.



Sole Supplier Risks:

We now have a direct relationship with our main IC manufacturer. We have visited their factory in Shenzhen and have secured a supply of this key component. The chip is extremely popular and there are no signs of this becoming unavailable. This being said, if the main radio chip were to suddenly be end of life, have production problems, or other issues, we would have to perform a major board re-design. We would still be successful at releasing a shield product even with a major board redesign.

HamShield for Arduino (VHF/UHF transceiver)
https://www.kickstarter.com/projects/749835103/hamshield-for-arduino-vhf-uhf-transceiver

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